global warming: global threat

Global Warming: Global Threat

Professor Michael B. McElroyHarvard University

The print book of this course guide may be purchased fromRecorded Books by calling 1-800-638-1304 or by visiting the

Modern Scholar website at www.modernscholar.com.

Global Warming: Global Threat

Professor Michael B. McElroy

Executive Producer

John J. Alexander

Executive Editor

Donna F. Carnahan

RECORDING

Producer - David Markowitz

Director - Matthew Cavnar

COURSE GUIDE

Editor - Eleanor M. Miller

Contributing Editor - Bobbie Patterson

James Gallagher

Designers - Will Lee

Edward White

Jeremy Reid

Lecture content ©2003 by Michael B. McElroy

Course Guide ©2003 by Recorded Books, LLC

2003 by Recorded Books, LLC

#UT006 ISBN: 1-4025-3915-0

All beliefs and opinions expressed in this audio program and accompanying course study guide are those of the author and not of Haights Cross Communications, Recorded Books, or its employees.

�

7

3

Course Syllabus

GLOBAL WARMING: GLOBAL THREAT

About Your Professor ....................................................................4

Introduction ....................................................................................5

Lecture 1 Perspectives on Earth History ................................6-11

Lecture 2 Stratospheric Ozone Depletion ............................12-17

Lecture 3 The Human Role of Life on Earth ........................18-23

Lecture 4 The Greenhouse Effect ........................................24-29

Lecture 5 The Efficiency of the Natural Greenhouse Effect..30-41

Lecture 6 Changing Concentration of CO2 ............................42-45

Lecture 7 Current CO2 Trends ..............................................46-49

Lecture 8 Methane, Nitrous Oxide, and OtherGreenhouse Gases ..............................................50-55

Lecture 9 Total Climate System ..........................................56-61

Lecture 10 The Role of the Ocean..........................................62-67

Lecture 11 The History of Climate Changes ..........................68-73

Lecture 12 Weather Modeling ................................................74-77

Lecture 13 Environmental Policy ............................................78-81

Lecture 14 Summary ..............................................................82-85

Glossary ..............................................................................86-87

Suggested Reading ......................................................................88

Course Text: McElroy, Michael B. The Atmospheric Environment: Effects ofHuman Activity. New Jersey: Princeton University Press, 2002.

4

About Your Professor - Michael B. McElroy

Michael B. McElroy received his PhD from Queen's University in Belfast,Northern Ireland. In 1970, he was named Abbott Lawrence RotchProfessor of Atmospheric Sciences at Harvard University, and in 1975 hewas appointed Director of the Center for Earth and Planetary Physics. Heserved as Chairman of the Department of Earth and Planetary Sciencesfrom 1986 to 2000. He was appointed Director of the newly constitutedHarvard University Center for the Environment in 2001 and now leads aninterdisciplinary study on the implications of China’s rapid industrial devel-opment for the local, regional, and global environment. In 1997, he wasnamed the Gilbert Butler Professor of Environmental Studies. He is aFellow of the American Academy of Arts and Sciences.

McElroy's research interests range from studies on the origin and evolu-tion of the planets to a more recent emphasis on the effects of humanactivity on the global environment of the Earth. He is the author of morethan 200 technical papers contributing to our understanding of human-induced changes in stratospheric ozone and to the potential for seriousdisruptions to global and regional air quality and climate due to anthro-pogenically related emissions of greenhouse gases. His recently publishedtext, The Atmospheric Environment, provides a comprehensive introduc-tion to the atmosphere, highlighting changes that occurred in the pastwhile offering context for the disturbances underway today as a conse-quence of human activity.

Pho

togr

aph

cour

tesy

of

the

auth

or.

5

Introduction

The issue of global warming has captured the attention of people world-wide over the past 20 years. Scientists looking at what humans are doingto the global environment believe that we are changing the climate of theplanet and that we are warming the Earth. If you think of the Earth the wayyou might think of the human body, the human body lives at a relativelyconstant temperature, 98 degrees or so, and if our temperature rises, weare sick. If our temperature rises 4 or 5 degrees, then we run the risk ofdying. So the issue is, are we risking the health of our planet? Are wecausing the climate to change? Are we causing our planet to warm up?What are the consequences of these actions?

This course examines the complex interdependent system that regulatesthe environment for life on Earth. The objective of this course is to providethe listener with a comprehensive account of the science that is underlyingthe environmental issues that have forced the people of the world to standup and pay attention.

Some of the problems we will discuss are air pollution, acid rain, deple-tion of the stratospheric ozone, destruction of tropical forests, and theresulting climate changes. We will also learn how greenhouse gases suchas carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and industri-al chlorofluorocarbons (CFCs) have all played a significant role in what ishappening globally today.

Upon completion of the course, the listener will better understand the over-whelming result of the human influence on the planet and what steps can betaken to better safeguard our environment in the future.

©N

AS

A

Lecture 1: Perspectives on Earth History

Introduction:

In this lecture we place the human influence in a larger geological context.

I. The Earth in the Beginning

The Earth is about 4.5 billion years old and life has been present almost fromthe beginning. Rock has been recovered dating back 3.8 million years, whichshows clear signs that life has been present on the Earth since or at leastsoon after it formed.

A. The Earth was formed from a spinning mass of gas and dust that repre-sents the original composition of the solar nebula. All of the planets,meteorites, the moon, and the sun that compose our present solar sys-tem were formed from the solar nebula.

1. The original nebular mass had a very high temperature but eventuallythe mass cooled down and elements began to form structures, parti-cles, and ultimately the primitive planets, comets, meteorites, and thesun. Particles began to coagulate and continued to grow until the Earthgot close to its present size.

2. The surface of this planet was composed mostly of liquid water with nocontinents, forming a planet-wide ocean. Over time, the radioactive mater-ial that composed the planet began to decay and provide an internal heatsource that caused the planet to turn itself inside out.

a. Material from the interior blasted all over the Earth and began tosettle and segregate, establishing the primitive Earth. This is howthe continents were formed.

i. Continents were formed when lighter rock that rose to the surfaceafter the decomposition occurred rested atop the denser rockfloating underneath the surface.

b. The early Earth had an atmosphere and an ocean. Through time, itbegan forming continents.

6

LE

CT

UR

E O

NE

6

Before beginning this lecture you may want to …

Read Nick Lane’s Oxygen: The Molecule That Made the World.

Consider this ...

1. We believe the Earth began over 4.5 billion years ago.

2. Organisms have existed on the planet since the beginning or soonthereafter.

3. Humans have only been on Earth for the last 150,000 years.

II. Early forms of life consisted of simpleunicellular organisms known asprokaryotes.

A. The life-forms at that time were fairlysimple. They had a very simplelifestyle, were single-celled organisms,had simple energy dependence, anddidn’t have a long life span.

B. Two theories exist on how life got here.

1. Seeds of life were formed elsewherein the universe or perhaps the outerregions of the primitive solar nebulaand it rained manna from heaven toprovide the seeds for the plethora oflife-forms we find here today.

2. Life formed in-situ in the earth. Thefirst area of the formation of life wasat the Black Smokey vents thaterupted in molten material into thedepths of the primitive ocean.

a. Scientists recently discoveredvents in the ocean floor wherewater at 300˚C was coming to thesurface with sulfur, chemicals, andother kinds of material. As thismaterial is released from thevents, it begins to condense in thecold ocean water. Around thesevents you find a remarkably com-plex but still simple life-form that isliving off the energy of the ventmaterial. These organisms takesulfur from the vents and use theoxygen present in the water andextract energy by oxidizing the sul-fur to sulfur dioxide creating sul-fate, in the process gaining theability to grow. Even today youcan find life-forms that exist andperpetuate from this process.

b. Genetic complexity developed asa consequence of the fusion of thegenetic material of these simpleorganisms, leading to the evolu-tion of organisms capable ofaccomplishing functions impossi-ble for their prokaryotic ancestors.

PROKARYOTIC VSEUKARYOTIC ORGANISMS

Prokaryotic, in the simplestterms, means “having a primitivenucleus.” These are single-celled organisms that lack amembrane-bound nucleus, havea single circular DNA strand thatlacks the proteins associatedwith a eukaryotic organism, andcan function in both aerobic andanaerobic environments.Prokaryotic organisms are mostfamiliar to us as blue-greenalgae and bacteria. One aston-ishing fact about these organ-isms is that they have beenseen to grow in both excessiveheat and cold.

Historically it is believed thatprokaryotic organisms appearedupon the Earth shortly after theEarth was formed, billions ofyears prior to the appearance ofeukaryotic organisms.

Eukaryotic organisms can besingle-celled organisms, such asprotozoa, or multicellular organ-isms such as humans. Theseare distinguished by the fact thatthey have cells with nuclei andthose nuclei are membrane-bound, contain organelles notfound in prokaryotic organisms,and have cells that are muchlarger in comparison. The genet-ic material is also more complexand held in the nucleus.

Although there are few similari-ties, both eukaryotic andprokaryotic organisms haveDNA that directs protein synthe-sis through mRNA and containsboth the messages for metabo-lism and chromosomal heredity.

77

c. Evolution proceeded slowly after the development of the early eukary-otes. A rapid profusion of life-forms, recorded in the Burgess Scale(Shale), took place roughly 1.5 billion years ago. The roots of many ofthe plant and animal species present today can be found in thisremarkable development. Evolution is not a steady Darwinian processwhere the strong survive and the weak die away. That’s not really theway evolution progresses. Evolution is in fact a process in whichchanges occur almost in steps. There are times of rapid environmentalchanges that lead to rapid change into the type of organisms that cansurvive it, resulting in winners and losers rather than weak and strong.Biologists refer to this as punctuated equilibrium. It’s not a steadyprocess but something that occurs in spurts, supporting rapid appear-ance and disappearance of organisms of various types.

C. The best publicized part of this is the history of the dinosaur.

1. Dinosaurs were common on the Earth with a wonderful variety of life-forms—big, clumsy, creative creatures that were all over the Earth liv-ing in an environment very different from today, probably when theEarth was quite a bit warmer. Over a relatively brief period of time, theEarth was smacked by a large meteor or by a series of meteors. Thesemeteors triggered global climate change. Most of the dinosaurs wentextinct over this brief period of time. But other life continued and newlife-forms developed.

2. Changes in the global environment, including changes in climate, hadan important influence on the evolution of new life-forms and on theextinction of organisms that were previously successful. Ecologicalniches were created and destroyed.

8

LE

CT

UR

E O

NE

8

ww

w.c

lipar

t.com

3. The human is a late arrival on thestage of life. Current studies suggestthat one species—homo sapiens—can be traced back to a commonmaternal ancestor who lived mostprobably in east central Africa about150,000 years ago.

a. These first ancestors lived verysimple lives, but with time theybecame more skilled and moremigrant and moved around theworld, initially into the MiddleEast and then into Europe, Asia,and the Americas.

b. From this early origin, humansspread to different parts of theworld. First arrival in the Americasoccurred as recently as 50,000years ago.

i. Fifty thousand years ago repre-sented mid-term or the lastmajor ice age that the planethas had. Sea level globally was120 meters, 350 feet or solower than it is today, and youcould walk from Siberia toAlaska through the BeringStrait. Humans arrived in theAmericas through this longmigratory path around this time.

ECOLOGICAL NICHES

Ecologists worldwide use“ecological niches” to help theo-rize mass extinction and oppor-tunistic evolution.

Studies have shown that everyplant and animal occupies a spe-cific “space” in an ecological sys-tem. It lives there, it eats there,and it reproduces there. Everyorganism alive will carve out aniche in an ecological systemand, providing the system isn’tdisrupted, can exist there forever.

When a niche is vacated,however, either through extinc-tion or disruption of the ecologi-cal system, the remainingorganisms see this as an oppor-tunity to expand their reach.This results in multiple speciescompeting to occupy the vacantniche. This opportunistic behav-ior will inevitably leave one win-ner and one or more losers dueto the fact that no two organ-isms can occupy the same eco-logical niche. This could resultin the extinction of one or moreof the opportunistic organisms.

When mass extinctions occurit is primarily due to the fact thatorganisms are fighting with eachother to gain control of thevacant niches. This againleaves winners and losers.

As we continue to grow andexpand, the ecological homes ofmany organisms are beingdestroyed and, along with that,many of those organisms arenear extinction.

99

Illus

trat

ion

©R

ecor

ded

Boo

ks,

LLC

.

ii. During the first period of humans inthe Americas the population wasn’tlarge, but the people did a fairamount of damage. When theyarrived this planet was rich withmegafana. Woolly mammoths werehaving a fine time living in theAmericas. In a very short time aftertheir arrival, our human ancestorshad eliminated many species.

Conclusion:

The history of the Earth and life can beviewed on a more comprehensible timescale. Imagine that the history of the Earth is compressed into a single year.Earth formed from the spinning mass of gasand dust that composed the primitive solarnebula in January. The early prokaryoteswere established by February 17. Almost 7months elapsed before the eukaryotesappeared in early September. Mammalsarrived on the scene first about December18, while dinosaurs disappeared onDecember 26. Humans made a lateappearance at about 9 p.m. on theevening of December 31. The industrialrevolution developed at about 2 secondsto midnight on December 31 and we aregrappling with events that will unfold overthe next few tenths of a second.

PUNCTUATEDEQUILIBRIUM

Punctuated equilibrium is a the-ory of evolution whereby organ-isms were not involved in contin-ual growth and change withintheir evolutionary time period, butthere existed times in the pastwhen no evolutionary changeswere occurring at all.

In 1972, two scientists, NilesEldredge and Stephen JayGould, proposed this as analternative to Darwin’s theory ofevolution. Their contention wasthat even though there may bebroken fossilized records, evo-lution in small groups occurredrapidly and eventually overtookthe parents.

This theory of evolution iscontradictory to Darwin’s theoryof continuous progression alongthe evolutionary chain—wherechanges occurred in smallsteps over time. Punctuatedequilibrium demonstrates, how-ever, that evolutionary changesoccurred rapidly and then lev-eled off where virtually nochanges were occurring at all.This represents equilibrium inthe ecological system.

10

LE

CT

UR

E O

NE

10

Illus

trat

ion

©R

ecor

ded

Boo

ks,

LLC

.

11

FOR GREATER UNDERSTANDING

1. What is man’s impact on the planet?

2. How does the process of extinction happen? Could it be avoided?

3. What are the very different theories of evolution?

Lane, Nick. Oxygen: The Molecule That Made the World. New York: Oxford University Press, 2003.

Liebes, S., E. Santouris, and B. Swimme. A Walk Through Time: From Stardust to Us: The Evolution of Life on Earth. New York: Wiley & Sons, 1998.

Gould, Stephen Jay. The Book of Life: An Illustrated History of the Evolution of Life on Earth. New York: WW Norton & Co, 2001.

Websites to Visit 1. www.isgs.uiuc.edu/dinos/dml/history.htm - Geological history of the Earth

presented in an easy-to-understand chart of time.

2. www.thinkquest.org/library - Comprehensive look at the scientific approach to dating our planet.

3. www.usgs.gov - Site of the US Geological Survey clearly outlining the biol-ogy, geology, and geophysical life on Earth.

4. www.extremescience.com/earth.htm - An exciting and interesting perspec-tive on the formation and history of our great planet. Site is filled with won-derful detail and a number of illustrations.

�Consider

Suggested Reading

Other Books of Interest

Websites to Visit


Lecture 2: Stratospheric Ozone Depletion

Introduction:In this lecture we will look at stratospheric ozone depletion.

I. The Ozone and How It Works

A. Ozone is present in the region in the atmosphere that we call thestratosphere, which typically begins 15 km above the surface of theEarth.

B. The stratosphere is the portion of the atmosphere where air stays for avery long time. It is a very stable environment. If you put “stuff” into thestratosphere it will stay there for years.

1. If a volcano erupts and the sulfur reaches the atmosphere, it will affectwhat happens in the stratosphere for the next 2 to 3 years and the dif-ference will be seen on the surface of the Earth.

2. Conversely, if you pollute the lower atmosphere, those pollutants willdissipate within a matter of weeks.

C. Ozone is formed in the stratosphere by ultraviolet sunlight, which haswavelengths shorter than we can see with our eyes. UV sunlight isabsorbed in the stratosphere by oxygen molecules that are torn apart inthe process. So you get separate atoms of oxygen where you had previ-ously cojoined pairs of atoms in oxygen. The chemistry of the stratos-phere essentially scrambles the oxygen molecules and you end up witha significant number of atoms arranged in a triatomic (O3) form ratherthan the diatomic form of oxygen (O2).

1. The importance of ozone is that it absorbs sunlight that would other-wise be extremely damaging to biological material. It absorbs light ofwavelengths that could fragment DNA molecules. Ozone protects thesurface from this form of radiation.

2. Scientists believe that if the ozone layer didn’t exist, life on the surfacewould be destroyed, or at least transformed.

3. Most ozone created in the stratosphere is also removed there and con-verted back to O2.

12

LE

CT

UR

E T

WO

12


Read Richard Elliot Benedict’s Ozone Diplomacy: New Directions inSafeguarding the Planet.

Consider this ... 1. What is ozone and how does it affect us?

2. Everyone has heard the term “hole in the ozone layer.” Is this term literal?

3. Are global warming and ozone depletion related?

a. Supersonic Transport (SST) is an air-craft that was first conceived in the1950s using governmental funds atBoeing. By the mid 1960s many politi-cians were questioning using govern-ment funds for the development of thisaircraft. This plane would have flownabout 20 km above the surface, whilenormal planes fly at 10 km above thesurface. So in order for this plane to flysuccessfully it would have to go intothe stratosphere. The exhaust from theplane would therefore be released intothe stratosphere where it would stayfor extended periods of time (1 lb ofpollution in the stratosphere will havethe same impact of hundreds ofpounds of pollution in the lower atmos-phere). Scientists began focusing theirresearch on nitric oxide, which is aninevitable by-product of plane exhaust.Nitric oxide has the potential to destroyozone, so scientists did some studiesto determine the effect of the SST air-craft on the ozone. The calculatedozone depletion was only a few per-centage points, which didn’t sound likea big deal until a meteorologist, JamesMcDonald, began questioning theeffect of a few percentage point loss ofozone and its effect on the surface andon humans. He began to study theincidence of skin cancer in an Irishcommunity in Houston, Texas, andcompare it to a similar ethnic group inMinneapolis and was able to discoverthat there was a higher rate of skin-cancer incidence in the southern citythan there was in the northern city. Heattributed this to the lower amount ofozone protecting the southern city ver-sus the amount of ozone protectingthe northern city. Through thisresearch he was able to calculate that1% depletion of the ozone increasedthe incidence of skin cancer by 2 to3% depending on the geographicallocation. Suddenly, a small amount ofozone depletion that was thought of as

1313

OZONE DEPLETION:AN ANALOGY

The best way to describeozone depletion is with ananalogy. Picture the ozonelayer as a bucket. If youpoured water into a bucket thathad holes in it but you wereable to add as much water aswas leaking out, the waterlevel in the bucket would stayat a stable level. If youpunched additional holes in thebucket but did not increase theamount of water you pouredinto the bucket, the water levelwould decrease. It’s the samewith the ozone layer. As more“holes” are punched into thestratosphere and more pollu-tants are reaching the stratos-phere, the ozone layer isdepleted, allowing for moreharmful UV sunlight to reachthe surface of the planet. Thiscreates serious environmentalissues and creates a genuinehuman health risk.

Illus

trat

ion

©R

ecor

ded

Boo

ks,

LLC

.

inconsequential was now a biggerproblem. His work was critical in thedecision of the government to sus-pend further funding of the SST air-craft project.

D. Chlorofluorocarbons (CFCs) were usedfor a whole variety of industrial purposes.In 1974, in the United States, 3 billionspray cans were sold in which the propel-lant was CFCs. The CFC gas was there-fore released into the air. CFCs were alsoused as cleaning agents, as refrigerants,automobile air-conditioning systems, andmore. This was a rapidly growing globalchemical product invented in the 1930s bychemists at General Motors. The CFCgas had the unique property of beingalmost indestructible. It was non-toxic,invisible, and non-flammable. A pair ofscientists discovered, however, that CFCgas eventually decomposed and releasedchlorine atoms. Chlorine atoms have thepotential to destroy ozone just like nitricoxide. Mario Malina and SherwoodRoland shared the Nobel Prize in chem-istry with Paul Crutzen for this discovery.

1. In the 1980s the models that predict-ed certain changes in the ozone lev-els in the atmosphere and the airquality at lower levels were discov-ered to be deficient. In certainregions of the world, the ozone start-ed to disappear, primarily overAntarctica.

2. Scientists began calling this theozone hole. This was an absolutelyunexpected phenomenon sincethere were no models to suggestthat it might occur. The loss ofozone over the polar region nowhad UV light that had never beenseen there before piercing thestratosphere and reaching the sur-face. Scientists became very con-cerned about the few humans, fish,and wildlife that live in the regionalong with the other biotic life.

BOEING AND THE SST

In the early 1950s when airtravel became popular, someengineers in the industry pre-dicted that in a short time air-craft would be developed thatwould fly passengers fasterthan the speed of sound—mak-ing the journey across theAtlantic take less than 5 hours.

Trying to beat the British andFrench, who were then devel-oping the Concorde, and theRussian KGB, who producedthe TU-144, the Congress ofthe United States of Americaappropriated $100 million forthe development of theSupersonic Transport. The yearwas 1964. Aviation companiesacross the country began com-peting for this lucrative opportu-nity that would revolutionize thecommercial airline business.

Boeing beat out Lockheed andNorth American and won thecontract to build the SST. Thatsame year, 1964, the Air Forcebegan testing Boeing’s super-sonic aircraft in Oklahoma. Asa result, there were over 8,000complaints about the sonicboom and 5,000 claims fordamages. This proved verycostly in and of itself.

Stronger opposition wouldcome from elsewhere though—American environmentalists.The SST was nothing but a gasguzzling polluter and was adetriment to the environment.By September 1969, more than$500 million in federal fundshad been spent on this projectand in 1971, the Senate endedthe federal funding andBoeing’s chances of success-fully developing the SST.

14

LE

CT

UR

E T

WO

14

It became a concern this phenomenonwould spread to the northern hemispherewhere more people were at risk. Globally,people decided it was time to do some-thing about it, eliminating the chemicalsthat cause the problems. A meeting tookplace in Montreal about the CFCs in 1986and it produced a document called theMontreal Protocol, which initiated theprocess of phasing out many of the CFCsand other chemicals that were suspectedof damaging the stratospheric ozone.

a. The Montreal Protocol determined thatwe needed to phase out the use ofthese chemicals in a relatively briefperiod of time and that the phaseoutshould involve developed as well asdeveloping countries.

b. It assessed penalties for non-compli-ance with the reduction of harmfulchemical production. These penaltieswere incredibly important. One of thepenalties for non-compliance was thatno country that signed the MontrealProtocol was allowed to import itemsthat contained CFCs from a countrythat was not a party to the MontrealProtocol. This had huge economicimplications for developing countries,especially in the automotive and elec-tronics industries.

c. The Montreal Protocol also madeavailable the Global EnvironmentalFund to developing countries. Thefund was financed by developed coun-tries through windfall profit taxes onthe CFCs. This fund aided the transi-tion of non-developed countries to anon-CFC future world.

i. It’s been a remarkably successfulventure in the sense that theamount of CFC gases in theatmosphere has now begun todecrease following the extendedgrowth that dominated from theearly 50s to the 80s.

DR. JAMES E. MCDONALDAND THE SST

James McDonald receivedhis PhD in physics from IowaState University in 1951. Hejoined the Arizona Universityfaculty in 1954 and specializedin meteorology. Although popu-larly known for his research onunidentified flying objects, hewas the first scientist to studythe impact our changing lifestylehad on the atmosphere and theozone layer.

When Boeing was developingthe SST, McDonald began tostudy the effects that the aircraftwould have on the atmosphere.In a statement to Congress inMarch 1971, McDonald clearlyoutlined what the SST would doto the ozone layer and the effectssuch as an increase in the inci-dence of skin cancer seen in theUnited States. In his address, hepresented three significant theo-ries as to what the effect of theSST would be. He deduced that1) the SST would be severelydamaging to the stratospherebecause the air didn’t clear fromthere as quickly, 2) as the dam-age increased the protection thestratosphere afforded woulddecrease, and 3) the incidencesof skin cancer due to this wouldraise considerably. He was right.

1515

3. Some positive messages were sent as aresult of the Montreal Protocol:

a. The chemical industry did not try toobscure the issue and formed anumbrella panel group of the majormanufacturers and joined with govern-ments in a global research program totry to understand the problem.

b. Industry was therefore not surprisedand was anticipating the transition tothe non-CFC world. Industryapproached the Montreal Conferenceknowing the problem existed and didnot try to politically or scientificallyavoid the issue. It turned into a coop-erative arrangement.

Conclusion:

Global Warming Issues

1. The economic interests that are at risk inthe global warming issue are enormouslylarger than the economic interests thatwere at risk in the CFC arena. The entireoil industry, coal industry, and fossil fuelindustry will be affected in some way bythe climate issue and the response onemight take to deal with it.

2. The developing countries were smarterby the time the climate issue camealong. They charged the developedcountries to make the first steps beforethey began considering any action oftheir own.

MONTREAL PROTOCOL

The Montreal Protocol was anagreement unlike any the worldhad ever known up until thispoint. The Montreal Protocolwas a treaty among all the par-ticipating countries to takeactive steps to protect thestratospheric ozone layer. Thistreaty was signed in 1987 andstipulates that the productionand consumption of certaincompounds (i.e., chlorofluoro-carbons, halons, and carbontetrachloride) were to bephased out by the year 2000.Scientists en masse agreedthat the prolonged use of thesecompounds would damage thestratospheric ozone layer andwould therefore no longer pre-vent the planet from receivingthe harmful UV rays generatedfrom the sun.

This original meeting, whichwas attended by over 50nations from around the globe,was followed up in 1990 and1992 where further proposalswere made to save the ozonelayer from further depletionand to fight the cause andeffect of global warming. Inlater lectures you will learn theresults of these conventions.However, it is important torealize that this was the veryfirst convention of its kind,where the world as a collectiveunit came together to fight thedamage to the global atmos-pheric environment.

16

LE

CT

UR

E T

WO

16

1717


1. What was the Montreal Protocol and what were the results?

2. How was the CFC issue brought to light?

3. What are the lasting effects of ozone depletion?

Benedict, Richard Elliot. Ozone Diplomacy: New Directions in Safeguarding the Planet. Massachusetts: Harvard University Press, 1998.

Makhijani, Arjun and Kevin Gurney. Mending the Ozone Hole: Science, Technology and Policy. Massachusetts: MIT Press, 1995.

Jurgielewcz, Lynne M. Global Environmental Change and International Law. New York: University Press of America, 1996.

Websites to Visit 1. www.epa.gov/ozone - Official site of the Environmental Protection Agency

providing a thorough look at the ozone situation.

2. www.al.noaa.gov/WWWHD/pubdocs/Strato3.html - This site sponsored bythe NOAA Aeronomy Laboratory provides an excellent resource for infor-mation on stratospheric ozone depletion.

3. www.nas.nasa.gov/About/Education/Ozone - NASA’s official site on thedepletion of the ozone layer and its effects on the planet.

4. http://wlapwww.gov.bc.ca/air/ozone - The official site of the Water, Air and Climate Branch of the British Columbian government provides a new per-spective on the global issue of ozone depletion.

�Consider

Suggested Reading


Websites to Visit


Lecture 3: The Human Role of Life on Earth

Introduction:

The Earth’s human population is over 6 billion and is still growing. Man’s influ-ence on the global environment is now undeniable. In this lecture we’ll examinewhen man and technology began to have an impact: the Industrial Revolution.

I. Problems That Arose in the Post-Industrial Period

A. The consequences of what we did were not often seen and perhaps if theconsequences of our actions were foreseen, it’s possible we would havetaken a different path. We traditionally react to problems once they havebecome an epidemic and the climate issue (global warming) is anotherchallenge that is precisely this type of situation.

II. The Industrial Revolution

A. The 17th century was a time when England was becoming relatively afflu-ent and had a presence that was spreading far beyond the British Isles.The Royal Navy was becoming significant globally and its maintenanceand expansion began depleting the British Isles’ natural resources. Theforested areas declined and it was difficult to meet the Royal Navy’s needfor tall trees for the masts of their ships so they could set sail. This countrywas rich and when a country is rich it allows for creativity in many ways.The affluence provides the opportunity for further creativity. However, withthe continued depletion of natural resources and the demand for products,this was the stimulus that led to the Industrial Revolution.

B. The Industrial Revolution was fueled by coal. That became the resourcethat substituted wood products, which were now in short supply. Englandhad abundant sources of coal but up to the time of the invention of Watt’ssteam engine, most of the coal was not accessible. You could track andmine only the stuff near the surface as England has a wet climate, and acoal mine that you are not pumping the water out of will become filled withwater very fast. The invention of the steam engine therefore allowed thecoal mines to be functional to greater depths. Afterward, England had anabundant source of energy.

18

LE

CT

UR

E T

HR

EE

18


Read Michael Williams’ Deforesting the Earth: From Pre-history to Global Crisis.

Consider this ...

1. Are humans changing the global climate?

2. Is the Earth warming up?

3. What can we do about it?

C. As the country becomes more industri-alized and more affluent, there areinevitable changes in the society.

1. Factories now become the site ofindustrial activity rather than homes,where most people used to work.You now have machines that bringpeople from the countryside to oper-ate. The country therefore under-goes urbanization and that rateaccelerates dramatically.

2. Industrial towns eventually emergeinto cities and they are often integrallybuilt around factories that belchsmoke from coal fires into the air.People are living in row houses, whichuse coal for heat and cooking. So theconsequence is that these cities veryquickly become dirty.

3. People took this for granted as partof city life. Rich neighborhoods andpoor neighborhoods soon devel-oped. The poor neighborhoodsalways had worse air pollution thanthe rich neighborhoods due to theirlocation near the factories.

D. Air pollution, notably sooty air, was thefirst signal of a problem. Initiallyaccepted as the price of progress,society moved eventually to deal withthis issue in the 1940s and 1950s,prompted by well-publicized disastersin Donora, PA, and London, England(the so-called killer smog of 1951).

E. Watts and other industrialists did notpredict what the outcome of industrial-ization would be. Problems began tobe recognized only recently.

III. Why did it take so long for pollution tobecome an issue?

A. Most people didn’t even think about theenvironment as something that neededprotection. There was no EPA, publichealth concern was focused on otherissues, and people had yet to recognizethe damage caused by air pollution.

1919

DONORA VALLEY

Up until the turn of the century,Donora, PA, was a small town ofmany names. First founded asPittsborough in 1814, the townhad a very undistinguished histo-ry. In May 1899, however, theUnion Improvement Companybegan to purchase large blocksof land in this little valley nestledbetween two mountains. In May1900, the Union ImprovementCompany broke ground for alarge industrial development.They were joined there by threesteel companies, a manufactur-ing plant, a fence company, andseveral others, which led to theindustrial boom of this tiny town.Soon the village was filled withworkers and their families, wholived a happy and healthy exis-tence until a strange meteorologi-cal event brought this tiny towninto focus—along with the dam-aging effects of industrialization.

On October 30 and 31 in1948, 19 people died suddenly,two of tuberculosis, and theremaining of heart failure andasthma. In addition to thesesudden deaths, over 500 peoplebecame ill and complained ofrespiratory problems. It was dis-covered that under normal cir-cumstances, the air that circu-lates between the mountainranges would drag the industrialpollution out of the area on adaily basis. However, at thistime, the pollution hung like theangel of death over the town.The term smog was now ahousehold word.

B. The solution to local air pollution involvedbuilding high smokestacks and sending theproblem elsewhere. This led to a newproblem—the issue of acid rain.

C. Acid: If you take any acidic material andpour it onto any metal surface, the metalsurface will dissolve. When you haveacid rain, as the rain becomes moreacidic, it leaches into the soil andbegins taking toxic metals out of the soiland transporting them into waterways,lakes, etc. These toxic metals thenbecome dangerous to the aquatic lifethat lives there.

1. When scientists discovered the effectsof industrialization on the environmentand acid rain was first observed, cer-tain changes that were previouslymade came into question. The initialreaction of lengthening of the smoke-stacks so that rather than remain in theimmediate vicinity, the smoke wouldtrail off somewhere else, obviouslycaused additional problems. To rectifythis, devices were built to filter out thepollutants before they got out in the air.Sulfur oxide and nitrogen oxide were ofparticular concern at this point.

2. The original increasing of the heightof the smokestacks helped to betterthe air quality in places likePennsylvania and London, but it didnot solve the problem elsewhere. Iteffectively moved the problem toanother location. The new region thatsuffered was the region downwind.

D. A further problem was recognized evenlater—the issue of photochemical smogor O3. This first came to attention in LosAngeles.

1. Another example of our inability to pro-ject what will happen comes when wetake a closer look at the automobile.This situation became dramatically evi-dent in Los Angeles, where the popula-tion there counted on the automobilefor transportation. Air quality was

ACID RAIN

Although industrialization wasan inevitable part of the culturein which we live, it didn’t comewithout a price. Killer smog inboth London and DonoraValley, PA, were steppingstones along the path of discov-ery on the effects of pollutionon our environment.

In Scandinavia, a relativelypristine environment with beau-tiful lakes, people began tonotice that the fish in the south-ern lakes of Norway werebeginning to die and disappear.As a result of this discovery,scientists began measuring theacidity of the lake water andfound that the lakes werebecoming more acidic.Someone decided to look at therain water and by capturing itand measuring the acidity theydiscovered that indeed the rainwas bringing more acidity totheir lakes. The rain was foundto contain increasing levels ofsulfuric acid and nitric acid.Norway was not a big industrialpower so scientists began look-ing at the way the wind cameacross the country. Germany,the UK, and Poland all werefound to be causing theincrease in acidity of the rain.So when it was decided to putthe smokestacks higher to dis-place the pollution to anotherarea, it created yet anotherproblem called acid rain. Acidrain occurred too in the UnitedStates. Its effects were feltmost severely in the northeast-ern part of the States but weregenerated from coal burningfactories mostly in the Midwest.

20

LE

CT

UR

E T

HR

EE

20

superficially very good. But thereseemed to be a particularly badstagnant air mass sitting over thecity and people started to get seri-ously ill. There was no clue as towhat was causing the increase in ill-ness and “coughing” throughout thecity. Haagan-Smit was the professorat the California Institute ofTechnology who first had the ideathat maybe automobiles were partof the problem. He began measur-ing the exhaust gases from hisautomobile and he subjected theseexhaust gases to a cycle of sunlightsuch as they would experience inthe outside environment. He discov-ered that ozone was being synthe-sized from the molecules compris-ing the exhaust if there was sunlightavailable to do this. So his discov-ery led to the conclusion thatexhaust gases can produce ozoneand ozone can make people sick.Even today, however, we don’tknow what level of ozone makespeople sick.

2. This resulted in the development ofthe catalytic converter—the catalyt-ic converter arrests emission ofsome of the chemicals responsiblefor ozone production.

E. Now we are confronted with climatechange arising as a consequence ofCO2, the primary product of combus-tion. These by-products are called“greenhouse gases.” Greenhousegases insulate the Earth from the coldtemperatures of outer space.

1. The energy we receive from the useand burning of fossil fuels essentiallyturns organic carbon into carbondioxide by adding oxygen atoms tocarbon. This process produces ener-gy. This is precisely what happenswhen we burn coal. Coal is com-posed of carbon atoms. Adding oxy-gen atoms will result in a chemical

2121

FORMULATION OF OZONE

Scientific researchers in the LosAngeles area attempting to learnthe cause of the “smog” that hungover the city were astounded todiscover that the culprit of theproblem was ozone.

Ozone was not a by-product ofindustrial production nor was itdirectly emitted from tailpipes orsmokestacks. Haagen-Smitalong with Margaret Brunellediscovered that ozone was cre-ated in the atmosphere. Theylearned that it is a photochemi-cal reaction, sparked by the sun,combining hydrocarbons from oilrefineries with exhaust of auto-mobiles, and nitrogen oxideswould join to form ozone.

Haagen-Smit and Brunelle con-ducted numerous experimentson the effects of ozone. Oneinteresting thing they discoveredwas that rubber disintegrated injust seven minutes after expo-sure to high levels of ozone.Tires in Los Angeles were wear-ing out fast.

Illus

trat

ion

©R

ecor

ded

Boo

ks,

LLC

.

reaction that releases a predictableamount of energy. The burning of coal,however, doesn’t make the coal disap-pear. It turns the coal into somethingelse. Matter is not created or destroyed!Coal is converted to carbon dioxide,which accumulates in the air. This worksfor oil as well.

2. Our solutions to all these problemshave been piecemeal. We use technol-ogy to clean up emissions. The prob-lems are not resolved; however, theimmediate issue may be remedied butnew issues, more recalcitrant,inevitably emerge. We simply transferthe problem to something else.

a. The carbon dioxide that is releasedinto the environment is going to bethere for a very, very long time. Fiftypercent of all the CO2 released in theenvironment since the start of theIndustrial Revolution is still present.

Conclusion:

The coal that we burn produces sulfur,which doesn’t stay in the atmosphere formore than a few days before it turns intoacid rain and is back on the surface of theEarth. Such problems would essentially goaway if we changed the way these com-pounds got into the atmosphere. But burn-ing fossil fuel and releasing it into theatmosphere continue to be a problem andappropriate measures need to be taken toalter this course of action sooner ratherthan later. We must also guard against thetendency of people to ignore the problem.

ARIE J. HAAGEN-SMIT

In 1947, a chemistry profes-sor from the California Instituteof Technology began to unrav-el the mystery of the denseand odoriferous cloud thathung over the city of LosAngeles, California.

Haagen-Smit, a Dutch per-fume chemist, knew that the airpollution was unlike anythinghe’d ever known and despiteefforts to control smoke fromfactories, a curious odor alsohung over the city. The smog,as it was termed, also led tosevere eye irritation. He deter-mined that the air was chieflycomposed of sulfur dioxide fromthe burning coal and oil in theindustrial plants.

Haagen-Smit was on the trailof a highly oxidizing element inLos Angeles air. By 1950, hisnose and research led him tothe culprit: ozone. By exposingplants to ozone in sealed cham-bers, he showed they sufferedsimilar symptoms as thosedamaged by smog.

Haagen-Smit also demonstrat-ed in the early 1950s thatozone caused eye irritation, res-piratory problems, and damageto materials.

2222

LE

CT

UR

E T

HR

EE

©P

hoto

Dis

c

23


1. What effect did the Industrial Revolution have on the environment?

2. What is acid rain and where did it come from?

3. What are we doing to prevent further pollution issues from arising?

Ray, Dixie Lee and Lou Guzzo. Trashing the Planet: How Science Can HelpUs Deal with Acid Rain, Depletion of the Ozone and Nuclear Waste. New York: HarperPerennial Library, 1992.

Williams, Michael. Deforesting the Earth: From Pre-history to Global Crisis. Illinois: University of Chicago Press, 2002.

Kosobud, R., D. Schreder, H. Biggs. Emissions Trading: Environmental Policy’s New Approach. New York: Wiley & Sons, 2000.

Websites to Visit 1. www.ec.gc.ca/acidrain/index.html - A complete look at the global issue of

acid rain and its effects on the global climate.

2. www.penweb.org/issues/mining - An interesting look at how the state of Pennsylvania deals with mining and its effects.

3. www.epa.gov/oar - From the Environmental Protection Agency, this site provides clean statistics on the increase in acid rain on our planet.

4. www.let.leidenuniv.nl/history/migration/chapter3.html - An excellent time-line resource for the Industrial Revolution and the consequences leading tothe issue of global warming.

�Consider

Suggested Reading


Websites to Visit


24

LE

CT

UR

E F

OU

R

Lecture 4: The Greenhouse Effect

Introduction:

The sun acts as the ultimate source of heat on the planet. In this lecture we’lltake a look at the ability to change the environment and how the role of the sunis changing.

I. Global Warming

The carbon dioxide that was released in the air after the Industrial Revolutionis the essential cause of global warming. You can try to remove the sulfuroxide from the smokestacks before it gets into the air, which is doable as thesulfur is a relatively small fraction of the total material produced by burningthe coal. It is much more difficult to remove CO2.The production of CO2 ismuch more critical than the release of sulfur oxide. This is the ultimate link toglobal warming.

II. The Greenhouse Effect

A. The ultimate source of heat on our planet is the sun. The center of thesun is a massive nuclear reactor burning hydrogen at the core at very,very high temperatures, which produces energy.

B. That energy is transported out through the different layers of the sun andeventually it is released in the form of light into space.

C. There are two principles that we need to consider.

1. The property of any body is that it glows and emits light. Basic physicalprinciples tell us that if we double the temperature of a body we canincrease the light radiating from the body by a factor of 16. Emissionvaries as the 4th power of the temperature.

2. The wavelength at which light is emitted depends also on the tempera-ture (i.e., if you warm up an iron bar and get it really hot, you begin to seeit glow). It initially glows a sort of reddish color, then yellow and thenwhite. Every body emits light: if the body is cold, light is emitted at verylong wavelengths you can not see with your eye; if it gets quite hot, youbegin to see the light coming from that body at wavelengths your eye issensitive to. We see with our eyes only a tiny part of the electromagneticspectrum of light. Different organisms have developed the ability to seelight in the different portions of the electromagnetic spectrum.

24

Consider this ...

1. What is the “greenhouse effect”?

2. What role does the color of the Earth play in the greenhouse effect?

3. What is the electromagnetic spectrum of light?


Read D. Crissoulidis’ Electromagnetics and Optics.

D. The outer regions of the sun are at atemperature of about 6 thousanddegrees and emit most of the sun’senergy in the visible spectrum at awavelength you can see (blues,reds, yellows, etc.). It’s not surpris-ing that species such as us evolvedto utilize the available spectrum oflight. We are basically diurnalbeings. We live most of our livesduring the day and we navigatearound by taking advantage of thefact that there is so much visible light.

E. The fuel that runs the climate systemis absorbed mainly at the surface ofthe Earth. A significant fraction of theenergy that is coming from the sun inthe visible spectrum is reflected backto space by clouds. The part that isnot reflected back by the clouds isable to reach the surface and bereflected back off the surface orabsorbed by the surface.

F. The average color of the Earth deter-mines how much light is absorbed/visi-ble and how much reflects back toouter space. The term scientists havefor this is albedo. Albedo is defined asthe measure of the fraction of light thatis absorbed. It has a range from zeroto one and is ultimately a measure ofa planet’s ability to absorb sunlight.

1. A certain amount of energy will beabsorbed by the planet from incidentsunlight and the rest will be reflectedback to outer space. That energy isnot stored. Otherwise, the Earthwould get hot. There is a lot of ener-gy coming in from the sun.

2. We can calculate the average tem-perature of the Earth by balancingwhat is absorbed from the sun withwhat is emitted to space. Calculatedin this way, the average temperatureof Earth turns out to be about –18ºC.

2525

INFRARED (NIGHT) VISION

When people hear the termnight vision they think of aJames Bond-type thriller wheregood overcomes evil becausethe hero has an awesome pairof night vision goggles. That’spartly true, but there is a fargreater application for the use ofinfrared vision than what isposed by Hollywood.

Visible light is only a fraction ofthe total light that is emitted fromthe sun. The amount of energyreleased by light is determinedby its wavelength. The shorterthe wavelength, the higher theenergy that is produced. Themid-range of infrared light has awavelength of about 2 microns,which is impossible to see withthe human eye. When you pointthe remote control at your TVand hit a button, mid-rangeinfrared energy wavelengths areused to change the channel foryou.

There are two applications ofinfrared vision. One is imageenhancing, which collects tinyamounts of light and amplifiesthem to the point where theycan be seen with the humaneye. The second is thermalimaging, which captures theupper portion of the light spec-trum, which is emitted as heat,and converts it to light. Thewarmer the item you are look-ing at, the brighter the imagewill appear.

Some of the most obvioususes of infrared vision are inthe military, law enforcement,wildlife observation, and hid-den-object detection.

a. The average temperature of theEarth is determined by a balancebetween energy absorbed from thesun and emission of long wavelengthinfrared radiation to space.

b. Greenhouse gases are very goodabsorbers of infrared light but verypoor absorbers of visible light. Theyare an ideal insulator that lets thelight in but doesn’t let the light out.

G. What this analogy (on left) has to do withglobal warming:

1. The sun is the global furnace and theoil is the nuclear energy that producesthe light that comes from the sun that isabsorbed by the Earth. The green-house effect provides insulation. Otherwise the Earth would be verycold. Giving the formula energy in =energy out and knowing how muchenergy is absorbed from the sun, thereis a simple calculation that a scientistcan do to calculate what the averagetemperature of the Earth should be.The average temperature of the Earthis –18˚C. The temperature required toget rid of the energy absorbed from thesun by the entire Earth is significantlybelow the freezing point of water. Theenergy that goes back to space doesnot come from the surface.

2. Selected components of the atmos-phere act as insulation on the Earth(these are the greenhouse gases).They inhibit emission of infrared (longwavelength of light) heat to space. Sothe greenhouse gases act as the roofon the Earth that maintains the interiorwhere we live at a relatively warm tem-perature. One would reasonably expectthat with more insulation, the Earthwould be warmer.

H. The major constituents of the atmos-phere (O2, N2) are unable to absorbinfrared radiation. If the atmosphere wassolely composed of these two gases, one

INSULATING A HOUSE NOTUNLIKE THE OZONE

As an analogy, consider ahouse heated in winter by an oil-burning furnace. The furnacesupplies heat and the energysupplied by the furnace is bal-anced by infrared radiation emit-ted to the outside by the wallsand windows. We could take aninfrared photograph of the housefrom the outside and observewhere heat was emitted. Forexample, the windows wouldprobably show up as hot spots.Well-insulated walls would becold; poorly insulated surfaceswould show up as warm.Consider now a second house,identical in construction, burningoil from an identical furnace atprecisely the same rate.Suppose that house is well insu-lated and the other is not. Couldwe tell the difference frominfrared measurements takenfrom outside? The answer is no.

Energy emitted from both hous-es would be identical becauseenergy in must equal energy out(otherwise the houses wouldeither heat up or cool down).Could we tell the difference if wewere to go into the houses?Yes; the well-insulated housewould be warmer inside.

26

LE

CT

UR

E F

OU

R

26

Illus

trat

ion

©R

ecor

ded

Boo

ks,

LLC

.

would expect the average temperatureof the Earth to be –18˚C. If the Earthwas frozen over, think about what thatdoes to the color of the Earth. If youtake the ocean, which currently looksdark and absorbs a lot of light, andcover it with a sheet of ice, it will lookwhite and not absorb very much sun-light. In this case, the albedo of theEarth will have decreased.

1. We require molecules with morecomplex structure (polyatomic mole-cules) to absorb infrared radiation.Of particular importance are H2Ovapor and CO2.

2. How can we reconcile this with ourexperience? The answer is thatemission to space does not occurfrom the surface but from high inthe atmosphere. The surface isinsulated by the greenhouse gasespresent in the atmosphere, notablyH2O and CO2.

I. How do we expect the Earth to respondto the input of more insulation?

1. If we add greenhouse gas to the atmosphere–increase the insula-tion–we might reasonably expectthe surface to warm. We are addingCO2 and other greenhouse gases tothe air and detailed calculationsindicate that the average tempera-ture of the surface should increaseaccordingly. This is the essence ofthe global warming issue.

2. The fundamental principle of thegreenhouse effect is that the majorgases in the atmosphere today (oxy-gen and nitrogen) do not absorbinfrared light. More complicated mol-ecules (water vapor and carbondioxide) are required to absorbinfrared light.

MONATOMIC, DIATOMIC,AND POLYATOMIC

MOLECULES

In the very basic sense, every-thing in our lives is composed ofatoms. Atoms are often referredto as the building blocks of mat-ter. When more than one atombonds together, they are referredto as molecules.

All atoms have central nucleithat are surrounded by varyingnumbers of negatively chargedparticles called electrons.

Some atoms are stable innature due to the fact that theyhave a sufficient number of elec-trons in their outer shells, pre-venting further electrons frombonding. These atoms are calledmonatomic. From the periodictable, noble gases are monatom-ic elements. Diatomic moleculesare composed of atoms withincomplete outer shell electronsand therefore pair with anotheratom to complete their outershell. Oxygen and nitrogen existprimarily in the atmosphere asdiatomic molecules. Polyatomicmolecules are combinations ofatoms bonded together to formstable, multi-atom structures.

Here are some examples:

2727

CH4

H

H

N2

He HeHelium

Nitrogen

Methane

CH

N N

or

or

or

or

or or

H

Monatomic

Diatomic

Polyatomic

ELECTROMAGNETIC SPECTRUM OF LIGHT

Since nearly the beginning of time, scientists have been speculating on theproperties of light. Sir Isaac Newton proposed that light was a stream of parti-cles bouncing off each other and forming light. But in the 18th century, a sci-entist named Thomas Young first theorized that light was not particles butwaves. His experiments in this area allowed him to deduce that light mustexist in waves because there were times when these waves cancelled eachother out. It is impossible for particles to do that. Although his theory wasrebuffed by many, renowned scientist Albert Einstein was able to prove thatlight existed both as waves and particles.

Much to the amazement of everyone, there is actually only a tiny strip of visi-ble light that exists in the whole spectrum of wavelengths of light. From radiowaves on one end of the spectrum to gamma rays on the other, there is avast difference in light. Very short wavelengths of light are exemplified by x-rays and tend to be absorbed high in the atmosphere. A slightly longer wave-length in the electromagnetic spectrum is the extreme ultraviolet, which isalso absorbed high in the atmosphere. These wavelengths literally tear atomsand molecules apart, producing electrons that provided the means for radiowave communications before we had satellites. Light in the ultraviolet portionof the spectrum is invisible to the human eye but visible to some organismsthat are able to navigate using ultraviolet reflectivity. Visible light is detectableby the human eye and has a variety of wavelengths also. Short wavelengthvisible light is blue and long wavelength visible light is red. Infrared wave-length is the next longest on the spectrum and is not detectable by our eyes.Microwave is the next in the spectrum and is absorbed pretty heavily bywater. Radiowaves are the next part of the spectrum and are lights of verylong wavelengths. These wavelengths may be miles long and have the abilityto penetrate into the ocean.

Solar energy, which governs our global climate, is delivered to Earth in theform of light. Some of that light is returned to space and some is absorbed bythe planet, allowing for a global energy balance.

28

LE

CT

UR

E F

OU

R

28

2929


1. What are the greenhouse gases?

2. What happens when the concentration of greenhouse gases increases?

3. What effect do greenhouse gases have on light?

Crissoulidis, D. et al. Electromagnetics and Optics. New Jersey: World Scientific Publishing Co., 1992.

Moroto-Valer, M. Mercedes et al. Environmental Challenges and Greenhouse Gas Control for Fossil Fuel Utilization in the 21st Century.New York: Plenum Publishing Co., 2002.

Gottinger, Hans. Global Environmental Economics. New York: Kluwer Academic Publishers, 1998.

Websites to Visit

1. www.panda.org - Home site for the World Wildlife Federation. There is an excellent section on climate change and its effects.

2. www.eere.energy.gov/climatechallenge - The official website of the Department of Energy, which discusses global climate change.

3. www.enn.com/specialreports/climate - Online information from theEnvironmental News Network with continual updates on climate changes.

4. www.climatehotmap.org - An interactive website that tracks up-to-date information on global climate changes, including storms, ocean level changes, melting glaciers, and general information.

�Consider

Suggested Reading


Websites to Visit


Lecture 5: The Efficiency of the Natural Greenhouse Effect

Introduction:

Carbon is an essential part of life. There is carbon in almost everything—butwhen is it too much?

I. Carbon on Earth

The Earth has a certain amount of carbon that is distributed between vari-ous parts of the surface layers of the Earth. There is carbon in the atmos-phere and in our bodies. Carbon is an essential element for life. There iscarbon in trees, green plants, sedimentary rocks, and soils. Carbon isabsorbed in the ocean. There is an enormous amount of carbon distributedover the Earth and the question is how does it move around and how is itdispersed?

A. It may be useful to tell a story about two other planets:

1. Venus actually absorbs less energy from the sun than does the Earth. Ifyou measured the temperature from the outside of Venus, it’s actually alittle colder than the Earth, even though it is sitting closer to the sun. Theroof of Venus is high above the surface and the surface temperaturesare searing hot. Venus is receiving less energy from the sun but the sur-face temperature of Venus is 750˚C. How can that be? Well, Venus’atmosphere is made of carbon dioxide, much more carbon dioxide thanthe atmosphere of the Earth, and the carbon dioxide in Venus’ atmos-phere plays a role as a greenhouse agent in insulating the surface fromouter space. A relatively small amount of visible sunlight gets to the sur-face of Venus but the energy produced at the surface has a very hardtime getting out because of the atmosphere that can absorb the infraredlight. So Venus has the mother of all greenhouse effects if you want totalk about it in that way.

2. Mars actually has more CO2 in its atmosphere than the Earth has, curi-ously enough. However, Mars is colder at its surface than the Earth, rela-tively speaking. The problem with Mars is that it is so far from the sun.It’s not absorbing that much sunlight and so despite the fact that it has afair amount of CO2, the atmosphere is too cold to hold much water vapor.

30

LE

CT

UR

E F

IVE

30


Read Naomi Oreskes’ Plate Tectonics: An Insider’s History of the ModernTheory of the Earth.

Consider this ...

1. What is the life cycle of an atom of carbon?

2. What role do tectonic plates play in the carbon cycle?

3. What occurs during photosynthesis?

So it has a greenhouse effect that ismarginally significant, despite the factthat it has a lot of CO2 in its atmos-phere.

3. So here we have three planets, Venus,Earth, and Mars, moving sequentiallyaway from the sun. For all three, CO2

is important, and we have more CO2 inthe atmosphere of Venus than in theatmosphere of Mars and more in theatmosphere of Mars than in the atmos-phere of Earth. Yet all three of theseplanets, we believe, came from thesame solar nebula. They formed in dif-ferent places, probably at differenttemperatures and slightly differentmaterials. They were also hit with thesame cometry material that fell in andhit these planets especially during theearly phases of their life histories. Allthree of these planets would havereceived inputs of water, vapor, carbondioxide, and nitrogen from outside.Carbon, nitrogen, oxygen, and hydro-gen are all the building blocks of life.

B. So how can we account for the differ-ences between the three planets?

1. Well, in the case of Venus, rememberthat it’s very hot and it’s closer to thesun. Had Venus started off with anocean of water vapor or of water, it’slikely that water would have evaporat-ed into space. We can make a casefor how hydrogen and oxygen wouldhave been lost into space. So ourbelief is that Venus might have begunwith a large amount of water but lost itover the early part of its life history.That has left CO2 more abundant thanwater on Venus. CO2 has accumulatedin the atmosphere and that’s the storywith Venus. Venus also has nitrogento a lesser extent; 7% of the atmos-phere of Venus is made up of nitrogen.

3131

MARS

VENUS

EARTH

©N

AS

A©

NA

SA

©N

AS

A

2. Let’s take the Mars story. Mars is cold.It also received water, CO2, and nitro-gen as it formed. What was the fate ofthe water? The water on Mars wasmore than likely in a frozen form andwas captured by the rocks. So Mars,we believe, has abundant amounts ofwater, but it’s frozen. If we could warmup Mars the rivers would flow. In thecase of carbon dioxide, carbon dioxidecan be absorbed by liquid. So theocean actually captures the carbondioxide that would otherwise be in theatmosphere of the Earth. If Mars doesnot have a liquid ocean, then the CO2 isstranded, so Mars has more CO2 in itsatmosphere than has the Earth. Marsalso has nitrogen in its atmosphere.CO2 is number one and nitrogen isnumber two, as far as abundance goes.

3. So let’s think about what happens onthe Earth. We have these primitive vol-canoes that begin to emit these volatilematerials (CO2, N2) from the interior ofthe Earth. We have comets that are hit-ting the Earth and bringing in morevolatile materials and they are evapo-rating and going into the air. The watervapor in these materials is going tocondense and create the primitiveoceans. So our expectation is that theEarth would have started its historywith this fairly large atmosphere of CO2.That large atmosphere of CO2 wouldhave provided a very potent green-house, so the early Earth would havebeen warm despite the fact that thesun is only beginning to generate itsnuclear energy. As the liquid oceanbegins to form, there is now the possi-bility of taking some of that CO2 andmoving it into the ocean. The waterabsorbs part of the CO2 and the con-tent of the atmosphere is now limitedby the capacity of the ocean to take up CO2.

ORGANIC MATERIAL

In a very basic sense, organ-ic material is the stuff thatplants and living organisms aremade of. From the beginningof time, the life and death ofearly organisms constructed alayer of organic matter atopour planet. As new plants grewand old ones died, the layer oforganic matter grew andbecame what we call soil.Through time, soil developedthe ability to acquire and holdmoisture, acting like a spongeduring times of heavy rainfall.This moisture allows the deadplants to decompose, releasingtheir vital chemicals into theatmosphere where they beginthe cycle of life all over again.

From a chemical standpoint,organic material is typically onecarbon atom, two hydrogenatoms, and one oxygen atom(CH2O). During the process ofphotosynthesis, oxygen isreleased into the atmospherewhile carbon dioxide is takenup. When the plant dies andbegins to decompose, carbonand water are released into theorganic material, which allowsother organisms to pick it upand use it to grow.

An interesting note to this isthat in areas near the poles,organic material is rare. TheArctic tundra, for example, hasvery little to no topsoil andtherefore does not produceorganic material. Any animalwho feeds off this will need tomove elsewhere.

32

LE

CT

UR

E F

IVE

32

II. The Carbon Cycle

A. The Volcano Erupts

1. A volcano erupts and vents water, CO2, and nitrogen into the air. Supposewe were to follow a carbon atom, color it blue, and watch what happensto it. It would stay in the atmosphere for maybe ten years.

B. Photosynthesis Begins

1. Photosynthesis is the process by which you take carbon dioxide, water, andlight from the sun and you transform the carbon dioxide and water into whatwe call organic material. It’s going to become part of a plant and perhapspart of the cellulose that allows a tree to grow.

C. Decay and Return to Atmosphere

1. A tree is formed in significant measure by carbon—carbon that waseventually taken out of the atmosphere as CO2 and converted into organ-ic material. Trees have a finite life: they die. Plants die. Bacteria arefeeding on and extracting energy from this decaying organic material andproducing CO2. So our blue-colored carbon that came out of the volcanomay have gone through a cycle from air to plant to soil and bacteria andback out to atmosphere.

3333

Illustration © Recorded Books, LLC.

34

LE

CT

UR

E F

IVE

34

TECTONIC PLATES

In 1912, scientist Alfred Wegener was the first to propose the idea that at onetime, all of the continents were one and that some geological force drove themapart. At that time, the lack of any evidence to support his theory left manyuncertain as to its validity. However, Wegener was determined to learn the truth.He discovered that fossilized remains located on South America and Africa wereidentical, proving his hypothesis that at one time, these two continents wereclose enough to share organisms. He believed that as the Earth rotated, thecentrifugal force of the planet’s orbit pulled the continents apart from the southpole and drew them toward the equator. After Wegener proposed this theory,physicists and mathematicians joined forces to calculate the rotational force ofthe Earth. They determined that there was an insufficient centrifugal force thatwould break up and pull the land masses apart.

By the 1960s, however, two other scientists, Harry Hess and R. Dietz,began examining Wegener’s theory and developed a theory of their own.Although much more information has been uncovered concerning the Earth’scrust and formation of planets, their original ideas are what sparked this mag-nificent discovery.

The Earth’s crust, called the lithosphere, is actually formed by segmentslaid out in a fluid mosaic atop the Earth’s surface. There are nine major tec-tonic plates and several smaller ones that form the jigsaw puzzle that we liveon. Most of the plates exist beneath land as well as water. There are twoplates, however, that exist singularly on one or the other. The Pacific Plate isan entirely oceanic plate where the Turkish-Aegean plate is entirely a landplate. The others are some variation of both.

Imag

e C

ourt

esy

Uni

ted

Sta

tes

Geo

logi

cal S

urve

y

D. Into the Ocean

1. The next trip around, that carbon may find itself in the ocean where ittransforms into a bicarbonate ion of one carbon, one hydrogen, threeoxygen, and a negative charge (HCO3

-).

a. Organisms living in the ocean are often enveloped by shells. That shellis made of calcium carbonate. So the carbon in the ocean can be usedto make the shell of a marine organism. Inside the shell you have theorganic material. The typical marine organism is microscopic and hasshelly material and organic material that is made photosyntheticallyfrom sunlight interacting with carbon and water in the ocean.

2. The ocean has its own life cycle. The photosynthetic organisms are at thebottom of the food chain. The ultimate source of the food in the oceandepends on energy captured by photosynthesis. There are also little organ-isms called zooplankton that eat the organic matter in these photosyntheticorganisms, and the food chain may go on to fish and larger animals. Insummary, there is a life cycle in the ocean that is fueled ultimately by foodprovided by CO2 transformed by photosynthesis.

3. Suppose an organism is not consumed by another organism. It dies andfalls to the bottom of the ocean. If it falls to the bottom and more materialfalls on top, it may be withdrawn from the ocean or it may be buried inthe bottom of the ocean sediment. If the burial is fast enough in localregions, the bacteria may not be able to keep up with the pace at whichthe dead bodies are raining down. So there is a net accumulation oforganic material at the bottom of the ocean going into sediments. Ourhypothetical carbon atom that came out of that volcano on day one hasgone through this complicated cycle many, many times, but eventuallyloses the game and finishes up dead at the bottom of the ocean. Howlong does it take to wind up dead? About 100,000 years.

a. Over those 100,000 years, that carbon atom is going to be many,many different times in the atmosphere, many, many different times indifferent plants and trees, many different times in the ocean and manydifferent times in living organisms both in the sea and on the land.

III. The Next Part of the Carbon Cycle

A. The bottom of the ocean is not a permanent grave. It’s a transient reser-voir. It’s a place where stuff goes for a little while before the tectonic platemotions of the Earth carry it away somewhere else. The sediments of theocean are not static. They are continuously moving on giant plates thatare driven by motions deep in the Earth. The crustal plates carry the sedi-mentary load deposited by the dead bodies raining down from above.

B. When Two Plates Collide

1. Two Possibilities

a. Part of the material may be uplifted. You can make a mountain out ofthe collision of the two plates, but under different circumstances thematerial of one plate can be subducted. It can be withdrawn deeperinto the Earth. It can sink below the plate with which it is colliding. Inthis process, you carry the carbon of the dead bodies down into the

3535

36

LE

CT

UR

E F

IVE

36

Earth, where the temperatures are very hot. At some point it getshot enough that the dead bodies are turned into CO2 and the waterbegins to turn into steam and the pressure of this water and steamand all the other things absorbed in it, including nitrogen andnotably CO2, cause an explosive release—that is what a volcano is.It vents explosively and knocks all the rock above out of the wayand you get a release of the volcano into the atmosphere. Now ourCO2 molecule is back in the atmosphere. In the sediment on theaverage is where it spends most of its life, maybe 100 or 200 millionyears. So the 100,000-year trip through the atmosphere, ocean,green plant, and living organisms is interrupted by burial. It staysburied for 100 million years but then it gets another chance. So lifebegins again, and the volcano starts the cycle. The CO2 goes backinto the atmosphere and the process begins again.

2. When we think about what we do by burning fossil fuel, it’s very impor-tant to see it in this natural context. The fossil fuels that we are talkingabout, coal and oil, represent the dead parts of organisms such as plantsand animals that were buried, sequestered, and withdrawn from the air.The means that nature has to get the carbon back into the atmosphereand begin the life cycle one more time, to keep the life cycle functioningand moving, is the one in which the volcano plays the critical role, butthe slow return from volcanoes is something we are now accelerating.Nature supplies carbon back to the atmosphere to offset the burial at arate we exceed 20 times today by burning fossil fuels. If you think aboutwhat we do by burning fossil fuel, we drill into the sediments, we find asource of oil, the chemically decomposed body parts of organisms livingmillions of years ago, and we bring those body parts carefully to the sur-face. We don’t wait for a volcano to process the material. We bring it tothe surface, then we light a match. We burn it and turn the stuff into CO2.So we are operating as part of the natural cycle, but we are acceleratingthat natural cycle. We do the same thing with coal, which representsplant material preserved in a frozen grave rich with organic material. Wego down and we drill into the coal mine and we bring the fossilized treesand plants to the surface and we light the match. We don’t have to waitfor nature to very slowly recycle that material as part of the tectonicmotion as part of the slow dynamic changes that regulate the motion ofgiant crustal plates that are so important to the history of the Earth.

a. We are accelerating a natural procedure and returning carbon to theatmosphere 20 times faster today than occurs in nature. Under thosecircumstances we see an increase in the CO2 content of the atmos-phere. Eventually the system will find its new equilibrium and CO2 willbe shared among the atmosphere, the ocean, plants, and soils.Eventually it will make its way into the sediments, but remember thecritical point. How long does it take the average carbon atom to getinto the sediments? We said in nature maybe 100,000 years. So thedisturbance that we initiate by burning fossil fuel is a disturbance thatis likely to be present at the surface for a very long time. The atmos-phere will store some of that carbon for a period that is measured in

hundreds of years. So even if westop burning fossil fuel instanta-neously, the excess that is presentin the atmosphere will only slowlydecay. It has to make its way even-tually into the sediments before thegame is over, before the disturbancehas been completely offset.

b. The famous oceanographer RogerRevell clearly saw the indication ofthe increase of this CO2 in theatmosphere as a disturbance ofnature he termed as man’s firstgreat global geophysical experiment.We are not just changing the atmos-phere, we are actually acceleratingone of these giant geochemicalcycles that distribute carbon amongthe range of parts of the Earth thatwe have talked about in this lecture.

IV. Oxygen

Another important element in the atmos-phere is oxygen. The atmosphere is com-posed primarily of nitrogen and oxygen.The nitrogen is the end product of thatvolcanic activity. Oxygen is produced byphotosynthesis. A common misconcep-tion, however, is that if you chop down allthe trees in the world, you will destroy theoxygen content of the atmosphere and alllife will end. That view is wrong. The oxy-gen molecules in the atmosphere cameoriginally from the photosynthetic joiningor marriage of CO2 and water. So to everyoxygen molecule there is a carbon atomsomewhere in the world in organic form,one to one. Oxygen molecules that are inthe air are married to carbon atoms in theorganic part of the sediments. If you takeall the trees in the world, and burnedthem, the amount of oxygen consumedwould lower the oxygen content of theatmosphere by a percent or so. To sig-nificantly deplete the oxygen content ofthe atmosphere you have to bring sever-al hundred million years worth of photo-synthetic activity to a halt.

ROGER REVELL

Roger Revell (1909-1991) wasone of the 20th century’s mosteminent scientists. After receiv-ing a PhD in oceanography fromthe University of California-Berkeley, he was affiliated withthe Scripps Institution ofOceanography and was later apart of the University ofCalifornia-San Diego.

Revell enhanced the status ofoceanography in world science,pioneered in the study of globalwarming, and brought a freshapproach to issues of population,world poverty, and hunger. Oneof his major accomplishmentswas his proposal that the continu-ing addition of fossil fuel-generat-ed carbon dioxide to the atmos-phere, oceans, and biospherecould lead to global warming. In1957, scientists from around theglobe began to join forces in whatwas called the InternationalGeophysical Year. During a con-ference of all 67 participatingcountries, Revell’s address stilllingers in the minds of scientistseverywhere. His famous quote:“Human beings are now carryingout a large scale geophysicalexperiment of a kind that couldnot have happened in the pastnor be reproduced in the future.”

Following this geophysicalyear, scientists made incrediblestrides in uncovering the truthabout the harmful effects of theburning of fossil fuels and carbon dioxide released into the atmosphere.

3737

A. Life, nature, and the Earth live in thiswonderful harmony in which elementsare not in competition but are mutuallysupportive. If we didn’t have the oppor-tunity to recycle carbon, we wouldn’thave life as we know it today.

B. Water vapor is the most important green-house gas in the atmosphere today. Ifthe atmosphere was primarily composedof O2 and N2, the greenhouse effectwould be minimal. Solar energyabsorbed at the surface would be reradi-ated directly to space.The average tem-perature at the Earth’s surface would bebelow 0˚C. As a consequence, the watervapor content of the air would beextremely low and the water vaporgreenhouse effect would be minimal.

1. CO2 provides insulation raising the sur-face temperature to the point where sig-nificant quantities of H2O can evaporatefrom the ocean. Water vapor amplifiesthe greenhouse effect. Eventually, thetemperature rises to where energyabsorbed from the sun is radiated tospace, primarily from the atmosphere.The atmosphere provides the insulatedroofing material to maintain the surfacetemperature at a relatively comfortable,global average, about 15˚C.

2. The CO2 content of the atmospherereflects equilibrium among the atmos-phere, land, plants, soils, and theocean.

3. A carbon atom present as CO2 in theatmosphere today can be taken up bygreen plants through photosynthesis.Plants can be eaten by animals, includ-ing humans. When we breathe, weextract energy by converting organic car-bon back to CO2. Carbon is recycled; itmoves from air to plants and soil to ani-mals and back to air in a never-endingcycle. Photosynthesis in the ocean is justas proficient as on land.

NITROGEN’S ROLEIN THE ATMOSPHERE

The element nitrogen alongwith oxygen constitutes almost99% of the Earth’s atmos-phere—79% of which is nitrogen.

Nitrogen gas, or N2, is thebasic building block of theatmosphere and is an extreme-ly stable molecule that can noteasily be broken down. It takesa significant amount of energy(lightning in the atmosphere) tobreak down an N2 molecule intonitrogen atoms.

All life requires nitrogen inone form or another. It is usedas a compound in the formationof proteins and nucleic acids.Proteins and nucleic acids arethe structural elements ofdioxyribonucleic acid—morecommonly known as DNA.Without DNA, life would ceaseto exist.

Nitrogen is also a critical com-ponent in the biotic cycle ofplants and animals. Nitrogen is broken down in this cyclenormally by microbes (bacte-ria). One of the significantplaces you will find this nitro-gen-fixing bacteria is in ricepaddies. Cyano-bacteria isessential to maintaining the fertility of the soil in these typesof aquatic environments.

3838

LE

CT

UR

E F

IVE

4. The sediments also are recycled. If not, life would run out of essential car-bon in a few hundred years. A critical question is how carbon gets from thesediments back to the atmosphere-plant-soil-ocean system.

5. Continental drift—plate tectonics—provides the answer. Carbon insediments is sucked into Earth’s interior where it is heated to hightemperature and vented back to the atmosphere by volcanoes andhot springs.

6. When we mine fossil fuel, we accelerate this natural component of thecarbon cycle.

Conclusion:

Today, by burning fossil fuel, we have far surpassed the process found innature. We are responsible for more than 20 times the quantity of CO2 pro-duced globally by volcanoes and hot springs over the course of an aver-age year.

CONTINENTAL DRIFT

In 1912, German geologist Alfred Wegener proposed the theory of conti-nental drift, stating that parts of the Earth’s crust slowly drift atop a liquidcore. Wegener theorized that at one time, there was a single huge land-mass covering the planet and surrounded on all sides by water. Fossilizedevidence has been found that proves that at one time, all of the continentswere close enough to share organisms. Similar to the action of the tecton-ic plates, continental drift involves the movement of the landmasses as weknow them today.

Interestingly enough, the continental crust is believed to be about 20 to 80kilometers thick and has an estimated age of about 3 billion years. Theoceanic crust, which lies beneath the ocean, averages 10 kilometers in thick-ness and is estimated to be hundreds of thousands of years old.

3939

4040

LE

CT

UR

E F

IVE

Illustration © Recorded Books, LLC.

4141


1. What is continental drift and how does it affect the climate?

2. How long does it take for a carbon atom to complete its life cycle?

3. How important a role does photosynthesis play in global warming?

Davies, G. F. Dynamic Earth: Plates, Plumes and Mantle Convection.Massachusetts: Cambridge University Press, 1999.

Oreskes, Naomi. Plate Tectonics: An Insider’s History of the Modern Theory of the Earth. New York: Westview Press, 2002.

Dalrymple, Rawdon. Continental Drift: Australia’s Search for a Regional Identity. Australia: Ashgate Publishing Company, 2003.

Websites to Visit 1. http://www.enchantedlearning.com/subjects/dinosaurs/glossary/Contdrift.

html - Great pictoral presentation of continental drift and tectonic plates.

2. www.usgs.gov - Home site of the US Geological Survey providing anexcellent resource for further information on the structure of our planet.

3. http://www.ftexploring.com/photosyn/photosynth.html - Comprehensivesite on exploring photosynthesis, the process, and the outcome.

4. http://www.galvnews.com/report.lasso?wcd=6614 - Interesting article onthe discovery of a new form of organic material that was brought to Earthas part of a meteorite.

�Consider

Suggested Reading


Websites to Visit


Lecture 6: Changing Concentration of CO2

Introduction:

In this lecture we will discuss how CO2 concentration is changing now and howit has changed in the past.

I. Scientists began to measure the atmosphere by direct sampling of airin 1958.

These measurements were pioneered by Charles David Keeling. His focuswas primarily on changes in the global concentration of CO2. Keeling decid-ed that the best place to monitor what was going on in the northern hemi-sphere was the middle of the Pacific Ocean and selected Hawaii specifical-ly. In Hawaii, he opted to gather his data from the top of a volcanic peak.He set up an instrument that would record CO2 almost continuously at thatparticular location.

II. In 1958, a group of scientists also got together to launch theInternational Geophysical Year.

This marked the first time a global political commitment was made to poolresources to better understand the Earth as a whole. It was also an opportunity,during the middle of the Cold War, for Soviet scientists, American scientists, andEuropean scientists to combine forces to address a variety of Earth issues.

A. One of the decisions made by this group of scientists was to placeinstrumentation in Antarctica. As the last unpopulated place in the world,Antarctica was a target of opportunity to set up stations that would pro-vide a record of geophysical parameters. The United States took on theresponsibility to build a permanent station at the South Pole. This is themost inhospitable place in the world. The Soviet Union, France, UnitedKingdom, Poland, and other countries also set up stations in Antarctica.Keeling asked the scientists to set up his instrumentation at the SouthPole to monitor CO2 concentration. So as of 1958, CO2 concentrationhas been continuously monitored at two stations, one in the northernhemisphere and one in the southern hemisphere (except for a brief tem-poral lapse at the South Pole).

42

LE

CT

UR

E S

IX

42


Read Coleman and Fry’s Carbon Isotope Techniques.

Consider this ...

1. Why were scientists concerned about CO2 concentration?

2. What methods were used to determine the age of the planet?

3. What were the scientific limitations of the time?

B. From the site in Hawaii, you canobserve a steady climb in the concen-tration of CO2 in the atmosphere, start-ing off at about 315 parts per million in1958 to 370 ppm in 2002.Superimposed on this steady climbyou see an up-and-down behavior.The curve goes up in fall and winterand down in spring and summer. Thisannual cycle reflects the growth ofvegetation in the northern hemisphereduring spring and summer, whichdraws carbon dioxide out of the air.The southern hemisphere shows asmall cyclic trend but since there is novegetation at the South Pole, thechanges aren’t as dramatic as we seein the northern hemisphere.

C. Determining the concentration of CO2

before the 1958 recordings takesadvantage of the fact that when itsnows in regions where the snow isaccumulating, air is isolated in thegrowing snow cover. And with furtheraccumulation air is isolated in littlebubbles in the ice under the accumu-lating snow. If you go to the centralpart of Antarctica there you have theopportunity to see very far back intime. The accumulation rate from yearto year is only a few centimeters orless but you have many, many yearsworth of accumulation. This accumula-tion allows you to go back 450,000years before present. From this450,000-year-old record scientistswere able to discover that CO2 con-centrations in the atmosphere overthis period have for the most partbeen limited on the high side to about280 ppm and limited on the low sideto about 200 ppm.

D. Over the last 450,000 years, the Earthhas wandered in and out of ice ages.These ice ages occur when watercomes out of the ocean and lowerssea level by about 120 m, with theextra water stored in these largeblocks of ice covering portions of the

CHARLES DAVID KEELING

Charles David Keeling (1928-)is a professor of oceanographyat Scripps Institute ofOceanography at the Universityof California-San Diego. Hereceived the National Medal ofScience in 2002 and is a worldleader in research on the car-bon cycle and the increase ofcarbon dioxide (CO2) in theatmosphere. Keeling was thefirst person to precisely mea-sure CO2 in the atmosphere ona continuous basis at two sta-tions located in Hawaii andAntarctica.

While monitoring the concen-trations, he discovered thatannual fluctuations existed withthe seasons. He attributed thisto the increase in vegetation inthe northern hemisphere.

Keeling was the first to recog-nize and substantiate the claimthat global atmospheric concen-trations of CO2 were rising. Inverifying his measurementstaken at both collection stations,he was able to produce thedata set now known as theKeeling curve.

4343

continents primarily in the northern hemi-sphere. These cold periods are associat-ed with the lower limit range of CO2. The280 ppm time periods are seen duringwarm parts of the cycle.

E. CO2 concentration in the deep distant past:

1. One way to help scientists determinethis is to find isotopic carbon deep in ocean sediments. If we look at ancientshells from the ancient ocean, we candetermine the age based on the oxygencomposition of the shell. Initial attemptsto determine the CO2 concentration sug-gest that the concentration was about1,000 ppm and since that time the con-centration level has obviously declined.Recent discoveries have been madethat suggest that in the deep distantpast, the Earth actually underwent aglobal ice age. This happened when thechange in the plate tectonics of theEarth reflected in the decrease of inputof CO2 below the point where the green-house was effective.

III. Recovering from an Ice Age

A. If the planet is iced over, all sunlight isreflected. However, volcanoes continueto move. Even though you’ve isolated theocean from the atmosphere by coveringit with ice, CO2 is put into the atmospherefrom volcanoes erupting above andbelow sea level. This allows the buildupof the greenhouse effect in the atmos-phere, which melts the surface ice andbrings the CO2-rich atmosphere in con-tact with the sea. These periods sparkedrapid evolution of life-forms on the Earth.A large number of species couldn’t make it and the survivors began to populate the niches that were vacated by the losers in this grand competition for space.

SURVIVING ANTARCTICA

A group of Russian scientistswas the first to attempt torecover ancient ice from thecentral heart of Antarctica.Recovery of air from this icehas allowed scientists to deter-mine past levels of CO2. Whilethe Russians were drilling theice, an equipment failure forcedthem to make a decision thatcould ultimately have cost themtheir lives.

Drilling in Antarctica is a long-term project. You can drill dur-ing the summer with heavy pro-tection gear. Come winter, theharsh climate precludes drillingfurther. When drilling, the holemust be filled with fluid to pre-vent closure over the winter orall progress on the ice hole willbe lost. A generator runs con-stantly to keep the liquid andthe core warm enough so thatyou can resume drilling the fol-lowing year.

One year that generator failedand the group of Soviet scien-tists who were wintering overhad two choices: use the gen-erator they were using to keepalive or give up the drilling siteand begin again the followingyear. The next year, the teamwas able to complete the pro-ject and it became a wonderfulrecord of the past.

44

LE

CT

UR

E S

IX

44

©P

hoto

Dis

c

4545


1. How did scientists eventually discover historical levels of CO2?

2. What is an ice age and how does the planet recover?

3. Why are CO2 concentrations different at each pole?

Bocknek, Jonathan. Antarctica, the Last Wilderness: Understanding Global Issues. New York: Smart Apple Media, 2003.

Coleman, D and B. Fry. Carbon Isotope Techniques. New York: Academic Press, 1991.

Long, John A. Mountains of Madness: A Scientist’s Odyssey in Antarctica. New York: Joseph Henry Press, 2001.

Websites to Visit 1. www.globaltechnoscan.com/27thDec-2ndJan/carbon.htm - Comprehensive

look at carbon cycling and what it means for life.

2. www.mrsars.usda.gov/morris/crisproj/carbon.htm - US Department ofAgriculture-sponsored research programs on carbon cycling.

3. www-bprc.mps.ohio-state.edu - Website for the Byrd Polar ResearchCenter specific to scientific study on the continent of Antarctica.

4. www.asoc.org - Website sponsored by the Antarctic and Southern OceanCoalition to promote education about this last untamed wilderness on theplanet. Includes excellent historical accounts of early exploration.

�Consider

Suggested Reading


Websites to Visit


Lecture 7: Current CO2 Trends

Introduction:

In this lecture we investigate the current trend in CO2 production by humankind.

I. In 1700 AD the concentration of CO2 in the atmosphere was about 280ppm. Over the last 300 years there has been a significant change in theconcentration of CO2 in the atmosphere.

A. Contributing Factors:

1. Use of fossil fuel, burning of coal, oil, and natural gas, is largely respon-sible for the current increase in CO2. Of these fossil fuels, coal is theworst in terms of quantities of CO2 produced per unit of energy delivered,followed by oil and then gas. Coal is black carbon and by burning it, youconvert that carbon to CO2.

2. We also have to consider the trends of burning oil. Oil is also a sourceof CO2. The chemical composition of oil is a little less carbon and a lit-tle more hydrogen than coal. So when you burn oil, the hydrogen isconverted to water and the carbon is converted to CO2. You get a littlemore energy production per unit of CO2 by burning oil than you do withburning coal.

3. Natural gas (methane) is CH4, meaning for every carbon atom there arefour hydrogen atoms attached to it. You get energy by turning the hydro-gen atoms into water and the carbon atoms into CO2. This producesmore energy per unit of CO2 than either oil or coal.

4. Deforestation, mainly in the tropics, represents a second importantsource of CO2. Burning timber is no different from burning coal in termsof CO2 production, especially if the timber is not allowed to regrow.Current evidence suggests that conversion of land from forest to grass inthe tropics is responsible for a source of CO2 equivalent to about onethird of that from fossil fuel. That makes countries such as Brazil andIndonesia as culpable as the United States and China for the currentincrease in CO2.

46

LE

CT

UR

E S

EV

EN

46


Read Michael Williams’ Deforesting the Earth: From Prehistory toGlobal Crisis.

Consider this ... 1. What is causing the current trends in CO2 production?

2. What effect is the burning of fossil fuels having on CO2 levels?

5. The Midwest of the United States is astrong agriculturally productive area.The area was unfarmed in the 1700swith the farming coming later stimulat-ed by the opening up of the west inpart as a consequence of constructionof the railroads. The soil in theMidwest is very thick, rich with organicmaterial and when it’s plowed andplanted, the surface layer of the soil isturned over and it stimulates the bac-teria to decompose that organic mat-ter. By oxygenating the soil, you areliberating nutrients, primarily releasingthe nitrogen that is accumulating there.In doing this, some of the microbesthat are now working on decomposingthis organic matter release CO2 intothe atmosphere.

II. By the late 19th century, however, it wasapparent that the increase in CO2 in theatmosphere was largely due to the burn-ing of fossil fuels.

The amount of CO2 added to the atmos-phere in the late 19th century is more thanenough to account for the increase of CO2

in the atmosphere. You can measure the concentration in the atmosphere and calcu-late how much the atmosphere is storing.

A. Some of the excess CO2 in the atmos-phere makes its way into the ocean andwe have to be able to make an estimateof how much is going to be absorbed bythe ocean. We need to understand thisin order to predict the amount of CO2

that will be retained in the atmospherein the future. The critical issue thereforeis determining how much CO2 can beabsorbed by the ocean.

1. The way the ocean works in contactwith the atmosphere is that, as thewind blows across the surface of theocean, gases in the atmosphere enterthe water and set up an equilibriumwhere they are entering and leaving atabout the same rate.

47

COAL, OIL, AND NATURALGAS: COMPARATIVE

The burning of fossil fuels,coal, oil, and natural gas, is thelargest contributing factor to theglobal warming problem. All pro-duce carbon dioxide as a by-product of burning, yet coal isthe worst by comparison.

In 1999 alone, the UnitedStates consumed 852.4 milliontons of oil, 551.2 million tons ofnatural gas, and 533.7 milliontons of coal. When coal isburned, it produces 2.86 shorttons of carbon dioxide forevery short ton of coal burned.Based on this analysis, morethan 1.5 billion tons of carbondioxide were released in theatmosphere in 1999. Thatnumber has steadily increasedover the years.

The United States is not alone.In 1999, the carbon dioxide emis-sions for the UK reached 1.4 mil-lion tons for coal, 1 million tonsfor oil, and 60 thousand tons fornatural gas.

As we move into the 21st cen-tury, researchers, scientists, andinventors are joining together totry to solve the CO2 emissionproblem. Under considerationcurrently are carbon sequestra-tion, carbon capture and sepa-ration and storage. At the pre-sent time, carbon sequestrationis cost prohibitive for most com-panies, approximately $300 perton of emissions avoided. By2015, however, the goal of thedevelopers is to have the cost at$10 or less per ton.

47

2. Release of CO2 due to deforestation in the tropics is offset by regrowth offorests, specifically at mid-latitudes of the northern hemisphere. The eastern portion of North America was largely deforested in the 18th and19th centuries as land was converted to agriculture. The process hasbeen reversed more recently as eastern US farmland was abandonedand as forests were allowed to recover.

3. At the present time, global use of fossil fuel accounts for a source of CO2

in excess of 20 billion tons per year, more than 6 billion tons of carbon.To put this in context, it represents a source of more than 3 tons of CO2

per year for every man, woman, and child alive on the planet. The UnitedStates, with about 5% of the world’s population, is responsible for about22% of global emissions. Again, in context, this means that, on average,Americans dump about 15 tons of CO2 in the atmosphere per year perperson. That makes CO2 the largest waste product we produce as anindustrial society.

a. But we are largely unaware of it. CO2 is nontoxic and invisible. Butwhen you drive around and empty your gas tank, the gas doesn’t sim-ply disappear. It largely turns into CO2. Likewise for the gas that youuse to cook or to heat your house, and for the coal consumed in apower plant to produce electricity.

Conclusion:

Fossil fuels are likely to supply the bulk of the world’s demand for energy for theforeseeable future. The demand in the larger developing countries such asChina is particularly impressive. China has abundant sources of coal, whichaccounts for close to 80% of China’s current primary energy use. The Chineseeconomy has been growing and is projected to continue to grow. The demandfor coal has increased accordingly. China is now the second largest emitter ofCO2, after the United States, and, given current trends, is likely to move to num-ber one at some point over the next few decades. Taking account of currenttrends and future demand for fossil fuel, most experts believe that emissions ofCO2 will continue to grow, driven to a larger extent than in the past by demandfrom developing countries. The concentration of CO2 is expected to exceed 700ppm by the end of this century in the absence of aggressive policy measure-ments to limit growth. This implies that CO2 levels will be larger in this centurythan at any time over the past 50 to 100 million years of Earth history—a sober-ing thought.

48

LE

CT

UR

E S

EV

EN

DID YOU KNOW?

Diamonds are the purest form of the element carbon? Carbon crystallizesunder tremendous heat and pressure, which occurs deep underground.Concentrations of diamonds large enough to mine are found in the Earth’soldest continental regions. Diamond is the hardest natural substance known,due primarily to its unique elemental bonding structure. Since all the carbonatoms are bonded together, they don’t break easily.

49


1. What is the greatest stumbling block for reducing CO2 emissions?

2. What role are developing countries playing in the increase of CO2?

3. What effect is deforestation having on CO2 concentration?

Barraclough, S. and K. Ghimire. Agricultural Expansion and Tropical Deforestation: Poverty, International Trade and Land Use. London: Earthscan Publications, 2000.

Williams, Michael. Deforesting the Earth: From Prehistory to Global Crisis. Illinois: University of Chicago Press, 2002.

Office of Technology Assessment. The Direct Use of Coal: Prospects and Problems of Production and Combustion. Toronto: Books for Business, 2002.

1. www.energy.gov/sources - Excellent website providing an in-depth look atfossil fuel production and usage worldwide.

2. www.fe.doe.gov/coal_power/sequestration/index/shtml - Incomparableresource for learning of the great strides the government is making ineliminating CO2 emissions.

3. www.millenniumenergyinc.com - Home page for Millennium Energy, Inc.,providing a thorough look at eliminating CO2 emissions.

4. www.wri.org/gfw - Home page for the World Resources Institute providinginsight into deforestation and its effects.


49

�Consider

Suggested Reading


Websites to Visit

50

Lecture 8: Methane, Nitrous Oxide, and Other Greenhouse Gases

Introduction:In this lecture we take a look at the other contributors to greenhouse gases:nitrous oxide and methane.

I. CO2 is the second most important greenhouse gas after H2O. Otherimportant greenhouse gases include CH4 (methane), N2O (nitrous oxide), thechlorofluorocarbons responsible for the hole in ozone over Antarctica, andO3 (ozone) itself.

A. Methane:

1. Methane is the second most abundant carbon compound in the atmos-phere. Carbon dioxide is the most abundant carbon compound in theatmosphere.

a. Current measurements place about 2 ppm of methane in the atmos-phere, significantly less than CO2. However, since it is 10 times moreefficient on a molecule per molecule basis in trapping heat, it is of con-cern. In light of this we can assume that one molecule of CH4 is doing10 times the damage of one molecule of CO2.

2. During the ice ages, the atmospheric concentration of CH4 was about300 parts per billion. During interglacial warm periods, CH4 concentration rose to about 600 ppb. Over the last 300 years, we observe a rapid riseof CH4 concentration that parallels the rise of CO2 except in manyrespects it’s been faster. Today we have 1,800 ppb concentration of CH4

in the atmosphere. So the proportional rise in methane has been largerthan the proportional rise in carbon dioxide.

3. Bacterially mediated decay of organic matter provides the dominantsource of atmospheric methane. The bacteria responsible for methaneproduction are most effective in environments where oxygen is in scarcesupply. One example is a swamp with stagnant water where plants andtrees grow. These bacteria are called anaerobes—they are anaerobic,which means without oxygen. Bacteria that function in an aerobic envi-ronment, one rich with oxygen, take up the organic material, join the car-bon from the organic material with oxygen, and then release CO2 as a

50


Read The National Academy of Sciences’ Methane Generation fromHuman, Animal and Agricultural Wastes Crisis.

Consider this ... 1. What role has agriculture played in greenhouse gases?

2. What are the drawbacks to using natural gas for alternative energy?

3. How has nitrous oxide influenced global warming?

LE

CT

UR

E E

IGH

T

by-product of this function. Whenthere is no oxygen available, aerobicbacteria are not able to function.When this occurs, the anaerobic bac-teria take over and process the organ-ic material. Rather than release CO2

as a by-product, since there is a lackof oxygen, the bacteria releasemethane, CH4. When released, thismethane contributes to the atmospher-ic burden.

4. Methane is best known as “naturalgas” that is also a fossil fuel. We knowthis is a fossil fuel because if we mea-sure for the amount of Carbon-14 innatural gas we discover that there isno Carbon-14 present, which signifiesthat this product is very, very old.Methane was most likely formed byanaerobic bacteria in the deposits oforganic material in the distant past.When oxygen ran out, the anaerobescreated methane. If you have a conve-nient geological reservoir beneath thesurface of the Earth where gas can bestored without escape then it accumu-lates over time.

a. Most deposits of natural gas arefound with oil. Often there is no effi-cient way to collect both the oil andthe natural gas, and deposits of nat-ural gas are burned in favor of thecollection of oil, which means thatnatural gas is burnt uselessly andconverted into CO2.

b. Burning vegetation at a smolderingrate, where very little oxygen isbeing consumed, also producesmethane and carbon monoxide. Thisoccurs during deforestation, clearingof lands for agriculture or in someareas where crops are burned tomake the land ready for the nextyear’s crops. If this is done in a“smoldering” way then methane is produced.

51

RADIATIVE FORCING

This is a measurement basedon a model. In order to deter-mine the radiative forcing ofCO2, you take the lower atmos-phere as it is today and youdouble the amount of CO2 thatis present. Then one calculatesthe amount of radiation that getsout to space. If you have moreCO2, less radiation gets out tospace. The difference is what isforcing the climate change. Youhave decreased the cooling andincreased the heating ability ofthe planet. This calculation isused to determine what theeffect of a greenhouse gasmight be. Methane is about 10times more important than isCO2. Nitrous oxide is about 100times more important than CO2

on a molecule per moleculebasis. Sulfur hexafluoride (SF6),which is used as an industrialelectrical insulating agent, is avery small part of the Earth’satmosphere but its concentra-tion is increasing at a significantrate. SF6 is good at absorbinginfrared radiation and thereforecontributes disproportionally tothe changing of the climate. SF6

remains in the atmosphere for avery long time. The efficiency ofthese gases to change the envi-ronment is assessed based onhow long a molecule remains inthe atmosphere once it gets in.One molecule of nitrous oxideremains in the atmosphere forabout 120 years since it isn’tabsorbed by vegetation or theocean. Molecules such as thesehave a long-term significantimpact on the climate.

51

52

c. Animals with a second stomach,ruminants, are also importantsources of CH4. Ruminants includecattle and sheep. Ruminants are ableto eat a low quality diet—grass forexample. Bacteria in the rumen con-vert this food to higher quality prod-ucts that can be assimilated by the animals. In the process, CH4

is produced and released to the atmosphere.

II. Why is methane increasing?

A. Domestic animals, or more specificallyruminants, produce a lot of methane.These animals eat low quality food likegrass, which is very high in carbon andcan not be easily converted to protein tobe useful to the animal. So they have adouble stomach, rumen, which allows theanimal to process this food and“upgrade” it through the use of anaerobicbacteria. Part of the anaerobic mecha-nism in these ruminants converts carbonto methane.

1. This is important because about 10%of what a cow ingests is converted tomethane.

2. The United States has a population ofover 110 million cows at any given timethat are used in both dairy and meatproduction. All of these cattle are effi-cient at producing methane.

3. The cattle population worldwideexceeds 1.2 billion.

4. This class of animal also includessheep, goats, and others.

B. Another contributing factor is the cultiva-tion of rice, which is the staple grain formany parts of the world. Much of the riceproduced is done in “controlled swamps.”A rice patty field is a wonderful environ-ment for the production of methanebecause the sediment is rich with eitherorganic material or fertilizer. Since ricegrows in water-logged soil, you createthe perfect environment for methane-producing bacteria.

RUMINANT FLATULENCE

Scientists (and most other stu-dents) are aware of the fact thatcows, sheep, deer, and otherlivestock have double stom-achs. They chew grass, swal-low, regurgitate, and swallowagain. During this process,which is called enteric fermenta-tion, the animal is converting thefood it eats into something use-ful for its body. Unfortunately,one of the by-products of thisbodily function is methane gas.

In the early 1990s scientistswho were involved in research-ing the increase of methane inthe atmosphere began lookingat the worldwide cattle industry.They discovered that over 80million tons of methane are pro-duced per year by ruminants.That equals greater than 20%of the entire methane produc-tion globally. This was a causefor great concern.

During the Kyoto Protocol(see Lecture 13) some scien-tists suggested significantlyreducing the amount ofmethane being released in theatmosphere would allow forless stringent restrictions oncarbon dioxide production.Some of the suggestions madeto reduce the methane concen-tration (which disappears fromthe atmosphere 10 times fasterthan CO2) involved geneticallyengineered cattle to alter thebacteria in their stomachs,improved grazing systems,alternate feeds to reducemethane production, and even vaccines to alter themicroorganisms.

LE

CT

UR

E E

IGH

T

52

53

1. Swamps provide an important naturalenvironment for these bacteria. Rice

paddy fields represent a human con-trolled swamp, in many respects anideal environment for CH4 production. A significant portion of the increase inCH4 is attributed to rice cultivation.

2. Once all of these things are consid-ered, rice cultivation, the proliferationof cattle, and other domesticated rumi-nants, it is easy to see how the con-centration of methane in the atmos-phere has increased.

3. It has been observed, however, thatover the last 10 years, the increase inmethane has been slowing down. Itremains unknown if that signifies theend of the rise. The number of cattlehas stabilized where it had beenincreasing previously parallel to thegrowth of the population. Rice cultiva-tion is also leveling off presumablybecause as much land is allocated forrice cultivation as is possible.

C. Other Sources of Methane

1. The other source of methane that weneed to be aware of is the by-productof methane from the production of fos-sil fuels. We saw a rise in the methaneconcentration in the 1990s with therise of the new Soviet Union. Thedecrease in the economy of the newRussia led to enormous inefficiency ininfrastructure.

2. The primary rises in methane arerelated to agriculture and food pro-duction. The demand of the peopleto eat rather than the demand of thepeople for energy is the most impor-tant difference.

III. Nitrous Oxide

A. Nitrous oxide, known more commonlyas laughing gas, is also produced bybacteria. Two classes of bacteria areeffective in this context. One operateslargely in media where oxygen is mod-

THE FALL OF THE SOVIET UNION

On November 9, 1989, millionsof people around the globewatched as the Berlin Wall col-lapsed—ending the decades-longstruggle of the Eastern Bloccountries of Europe. Most ofthem were economically, scientifi-cally, and financially destitute andthe resulting struggle to rebuild anation out of those ruins causedan identifiable and extreme effecton global warming.

Much of the former SovietUnion was in disarray. Theinfrastructure of the countrywas in shambles. Along theTrans-Siberian railroad lay oneof the Soviet Union’s mostimportant economic entities—natural gas pipelines that hadbeen built along the rail trackto transport gas from Siberiainto civilized Russia. Thisstretch of pipeline was poorlymaintained, however, and gasallowed to leak out into theenvironment. Therefore, natur-al gas flowed freely out of thepipeline unchecked, oftencausing massive explosions.All of this had a major impacton the increase of methane inthe atmosphere seen in theearly 1990s.

53

©P

hoto

Dis

c

54

erately available. It plays an important role converting reduced forms ofnitrogen, ammonia for example, to more oxidized forms such as nitrite andnitrate. Nitrous oxide is produced in this manner as a by-product of whatwe refer to as nitrification. Nitrous oxide is also produced by bacteriaunder low oxygen conditions, as a by-product in this case of reduction ofnitrate, a process known as denitrification.

B. Nitrous oxide is about 100 times more efficient molecule per molecule thanCO2. The concentration of nitrous oxide is also increasing at about thesame rate as CO2. The current concentration is about 310 ppb. Scientistsno longer believe that this is a by-product of burning coal. Now scientistsbelieve that the major source of nitrous oxide is bacterial and what isobserved is a human forcing of the nitrogen cycle that is provoking anincrease in nitrous oxide production by bacteria that are basically process-ing nitrogen both as human waste and animal waste. Importantly, as wecreate our own food today, we are creating our own nitrogen fertilizer. Weare chemically producing nitrogen fertilizer and spreading it on fields. Inorder to do this, we take molecular nitrogen out of the air that is uselessfrom a biological point of view and convert it to ammonium nitrate or sul-fate that can be delivered to the fields in the form of fertilizer. We areadding chemical fertilizer to soil, stimulating the bacteria, and in returnstimulating the production of nitrous oxide.

Conclusion:

The increase in nitrous oxide can be attributed to food production, waste pro-duction, and to the six billion people (and that number continues to rise) whopopulate our planet. Thus, if the increase in CO2 is largely due to energy-related activity—consumption of coal, oil, and natural gas—the increase inCH4 and N2O must be attributed primarily to processes relating to agricultureand waste disposal. Ultimately, the increase in CH4 and N2O reflects growthin human population and affluence favoring a diet of animal and animal prod-ucts in contrast to plants (grains for example). Worldwide, we feed abouttwice as much grain to domesticated animals as we ingest directly ourselves.

54

LE

CT

UR

E E

IGH

T

5555


1. How has the cattle industry affected the global warming issue?

2. Why was the end of the cold war a serious contributor to the increase inCH4 concentrations?

3. What role do bacteria play in methane production?

Clark, M. and A. Brunick. Handbook of Nitrous Oxide and Oxygen Sedation. New York: Mosby Press, 1999.

National Academy of Sciences. Methane Generation from Human, Animal and Agricultural Wastes. Toronto: Books for Business, 2001.

Ljungdahl, Lars G. Biochemistry and Physiology of Anaerobic Bacteria. England: Springer Verlag, 2003.

Websites to Visit 1. www.epa.gov/methane - Official website of the Environmental Protection

Agency discussing methane emission control.

2. www.csmonitor.com/2002/0103/p3s1-usgn.html - Excellent article that appeared in the Christian Science Monitor about the capture of natural gas.

3. www.ciesin.org/TG/AG/liverear.html - Site provides an in-depth look atlivestock and the methane issue.

4. www.findarticles.com/cf_dls/m3066/n6_v160/20411079/p1/article.jhtml -Gripping article on nitrous oxide emission and the control of these emis-sions.

�Consider

Suggested Reading


Websites to Visit


Introduction:

In this lecture we will concentrate on the role of the atmosphere.

I. Energy Balance of the Earth

A. In the tropics, significantly more energy is absorbed from the sun than isradiated back out to space in the infrared. “Tropics” indicates latitudes of+/- 25 .̊ Here is a region where the Earth is gaining energy in excess ofwhat it is returning to space. In the extra-tropics, latitudes greater than 25 ,̊there is an energy deficit. Less is being absorbed than is sent back intospace. Taken as a whole, the Earth maintains an approximate energy bal-ance: energy absorbed from the sun on a global basis is balanced more orless by energy radiated to space.

1. There are two ways to move energy:

a. Circulation of air; energy from the low latitudes is transported to thehigh latitudes.

b. The ocean; currents take energy from low latitudes to high latitudes.

2. The climate of the Earth is basically determined by the energy imbalancebetween low latitudes and high latitudes, and the response of air andwater to that imbalance. A portion of the energy excess in the tropics istransported to higher latitudes to offset the energy deficit in the extra-trop-ics. An approximately equal amount is transferred by the ocean.

II. Circulation of Air

A. Warm air rises in the tropics, drawing moisture from the warm oceans.There are three regions of tropics in which the air rises in particular. One isin Indonesia, in the Western Tropical Pacific. The second is over theAmazon Basin in South America and the third is in Africa. In other parts ofthe tropics the air isn’t rising, it’s actually sinking. These are called strongcenters of convective activity. Air moves from the equatorial area to higherlatitudes at an altitude of 10 km or so above the surface. This is how thewarm dry air is moved from one area to another. Tropical air is unable,however, to make it past latitudes of about 30 .̊ Once it gets to this region,

5656


Read Dennis L. Hartmann’s Global Physical Climatology.

Consider this ...

1. What does energy balance mean?

2. What are trade winds and how do they affect the global climate?

3. What is the jet stream?

Lecture 9: Total Climate System L

EC

TU

RE

NIN

E

it now begins to sink back to the surface.The rotation of the Earth prevents it fromrising above 30˚ latitude and causes it toturn to the east. Eventually it runs out ofmomentum toward the poles and sinksback to the surface. It returns to the trop-ics at the surface, setting up a circulationloop known as the Hadley circulation,named in honor of the English meteorol-ogist, George Hadley, who firstdescribed this process more than 250years ago.

1. As it begins its journey at the surface inthe tropics, the air contains a relativelylarge content of water vapor. Watervapor is removed by rain as the airrises. As the air moves to higher lati-tudes, its moisture content is severelydepleted. The sinking portion of theHadley circulation is responsible for theband of deserts that ring the Earth inthe subtropics—the Sahara, for exam-ple. It rains where air rises. It is dry andhot where it sinks. When we thinkabout possible climate change, weneed to think about the implications forthe latitudinal extent of the Hadley cir-culation. An expansion of deserts tohigher latitudes would have important implications for those who live on themargins. For that matter, a retreatwould also be significant.

III. Trade Winds

A. Trade winds are surface winds that blowfrom the southeast in the southern hemi-sphere and from the northeast in thenorthern hemisphere at a generally reli-able clip. This is the return flow of theHadley circulation.

B. This is how air is exchanged betweenequatorial regions and mid-latitudes.

IV. Air Circulation at Higher Latitudes

A. We must think of this in terms of sum-mer and winter. In summer, the Earth isgetting a lot of energy from the sun atthe higher latitudes, because of the tilt

57

GEORGE HADLEY

George Hadley (1685-1768)was an English physicist andmeteorologist. He directedmeteorological observations forthe Royal Society and formulat-ed the first theory describing thetrade winds and circulation pat-tern now known as the Hadleycell. In 1735, Hadley publishedhis theory in a famous paper“Concerning the Cause of theGeneral Trade Winds.” Hadleyrealized that wind particles mov-ing toward the equator wouldcome from a region of lowereastward velocity and enter aregion of higher eastward veloc-ity as they move toward theequator. Thus, the wind wouldhave a westward motion.

Almost 100 years after pub-lishing his famous paper,Gustave-Gaspard Coriolis pro-duced the equations that provedHadley’s theory of the tradewinds rotational system.

Interestingly, it wasChristopher Columbus who rec-ognized the utility of the tradewinds on his infamous voyageacross the Atlantic. He observedthat trade winds could powertranscontinental shipping, espe-cially when heading from westto east across the Atlantic.

57

of the axis of the Earth. In the polar cir-cle, for example, the sun is shining 24hours a day. In winter, however, youhave the exact opposite. In these areas,the summer climate is virtually workingon its own. In the winter, you don’t havea lot of energy input from the sun,allowing the surface to get really cold. Inpolar regions it does get cold, but not ascold as it could be, because of the ener-gy supply coming from the atmosphereand the ocean at lower latitudes.

B. There is a relatively sharp transitionbetween warm tropical air and cold highlatitude air, especially in winter. Thisboundary is marked by a stream of high-speed air travelling in a generally west-to-east direction around the Earth. Thissystem is referred to by meteorologistsas the jet stream. The velocity of the jetstream is highest at an altitude of severalkilometers above the surface in thenorthern hemisphere. On the high lati-tude side of the jet stream, the air is cold.On the low latitude side it is warm. Thegreater the difference in temperaturefrom the warm to cold side, the higherthe speed of the jet stream.

1. The jet stream does not always maintaina constant latitude as it flows around theEarth. Occasionally, it can develop a sig-nificant meander: it can swing temporari-ly in a loop to higher latitudes in oneregion with a compensating loop to lowerlatitudes elsewhere. Those of us wholive in cold winter regions such asBoston have frequently experienced thedramatic impacts of such swings in thejet stream. Temperatures can jump bytens of degrees in a matter of hours asthe jet stream migrates from south tonorth, as a major meander passes over-head. We can go from cold to warm thenback to bitter cold in a matter of days.

2. Whether winters are mild or colddepends on where we live relative tothe average position of the jet stream.

58

THE JET STREAM

Anyone who’s ever heard aweather report has heard theterm “the jet stream.” The localweather person always hasinteresting graphics to demon-strate the flow of air acrossthe continent. It’s easiest toconsider the jet stream to be ariver of fast-moving air, highabove the surface of theEarth. It moves from west toeast and generally at speedsgreater than 60 mph anddivides colder air in the northfrom warmer air in the south.

Movements in the flow of airare the largest contributing fac-tors to the ambient temperaturefelt when you walk out the door.If the jet stream dips south, it’spulling very cold air from thepolar regions down and theresult is frigid temperatures inthe area above the jet stream.When the jet stream flowsacross the northern part of thecontinent, the area belowenjoys balmy temperatures.

Severe weather is triggeredby changes in the jet stream.Jet streaks are pockets of windmoving at a faster rate than thejet stream as a whole. As thesejet streaks travel, they are mod-ifying the air pressure along thejet stream. As it pulls the airhigher, it creates a low pres-sure situation on the surface ofthe Earth, which is favorable forprecipitation and storms. Inhigh-pressure areas, thewarmth prohibits the formationof clouds, leaving only sunnydays in its wake.

58

LE

CT

UR

E N

INE

59

3. A key question for the future concernsthe response of the jet stream tochanges in the energetics of theatmosphere arising as a consequenceof the increasing burden of green-house gases. In general, we mayexpect winters to be milder. This maybe considered a boon for those wholive in regions that are presently coldin winter. But a change in winter cli-mate can have important implicationsfor ecosystems. The type of vegeta-tion that grows in a particular regionhas adjusted to a particular climate. Ifthe nature of this climate regime wereto change dramatically and rapidly,natural ecosystems might find it diffi-cult to adjust.

4. The atmosphere is often unstable inthe vicinity of the winter jet stream.These instabilities take the form ofstorms that can spin off and carry air tohigher latitudes. Meteorologists refer tothese instabilities as eddies. Eddiesplay a very important role in carryingheat from low latitudes to high lati-tudes, especially in winter.

V. Jet Stream: Land vs Sea

A. The ocean maintains relatively the same temperature from day to night or indeed from day to day. This is possiblebecause the wind is churning up 10 to100 meters of surface water, allowingthe heat to be stored in the summer andreleased in the winter. The ocean is agood way to store heat.

B. Over the land, the heat that’s absorbedfrom the sun in the summer is absorbedright at the surface. The continent willheat up during the summer and cooldown during the winter. This sets up avery important circulation loop thatworks like this:

1. During the summer, you are warmingup the continent. Air over the continenttends to rise and then sink over thebordering ocean. So you build up

DEVELOPING STORMFRONTS

At the Earth’s surface, atmos-pheric pressure is the key tounderstanding the weather. Airin a high pressure area com-presses and warms as itdescends. When the air iswarm and dry, formation ofclouds is inhibited, meaning thesky is normally sunny in high-pressure areas. Just the oppo-site occurs within an area oflow pressure. In areas of low-pressure, the air is rising andcooling down. The cooler airforms clouds and precipitation.

When the weather man saysa low pressure area is movingtoward your region, cloudyweather and precipitation resultas the low-pressure areaapproaches. Low-pressure sys-tems have different intensitieswith some producing a gentlerain while others produce hurri-cane-force winds and a mas-sive deluge.

Thunderstorms are the keyingredient in most severeweather. Lightning results froma buildup of electrical chargehigh in the atmosphere.Thunder happens because light-ning heats the air to more than43 thousand degrees, causingthe air to expand. As this aircools, it begins to contract. Thisquick expansion and contractionof air around the lightning startsair molecules moving back andforth, making sound waves,which we hear as thunder.

59

60

high pressure over the ocean andlow pressure over the land. Thisprocess is reversed in winter.

2. The Indian monsoon is another ele-ment of the land/sea circulation.During the monsoonal period theIndian continent warms up and thecirculation is generated by the low-pressure system on the Indian sub-continent and the high pressureoutside coming from the ocean. Asthis air comes across the ocean, itpicks up moisture and drops rain onthe continent. In the winter, theopposite happens.

Conclusion:

1. The total amount of rain is limited by theamount of evaporation that occurs from theworld’s oceans. It can’t rain more than itevaporates. The water vapor in the atmos-phere doesn’t stay there very long.

2. Evaporation is the result of heating up abody of water, energy driving water fromthe liquid to the gas phase. Absorption of sunlight on the surface of the world’soceans plays a major role in determininghow much evaporation is going to takeplace and consequently how much rain-fall will occur.

3. We have focused here on the role of theatmosphere in transporting heat from thetropics where the energy balance (the dif-ference between heat absorbed from thesun and infrared radiation emitted back tospace) is positive, to higher latitudes,where it is negative. In the next lecture, weturn our attention to the role of the ocean.

MONSOONS

The word monsoon is derivedfrom the Arabic word “mauism,”which means season. It is usedto describe the seasonalchange in the direction of thewinds that develop as a resultof pressure changes in theatmosphere. The best-knownmonsoons are those that affectIndia and Southwest Asia.

There are two well-knownmonsoon patterns. The summermonsoon blows southwesterlyacross the Indian Ocean andcauses very wet conditions. Incontrast, the winter monsoonblows northeasterly and is gen-erally dry.

India and Southwest Asia liebetween two climate zones, thetropical and subtropical. In win-ter, the northeasterly flow ofwind goes from the subtropicalhigh-pressure area to the tropi-cal low-pressure, creating dryweather. In summer, however,as the continent of Asia heatsup, it creates a seasonal lowpressure area bringing with itrain and wind.

Scientists believe that theintense South Asian monsoonphenomenon was created about20 million years ago when Indiacollided with the Asian continent,resulting in the Himalayas andthe Tibetan Plateau.

60

©P

hoto

Dis

c

LE

CT

UR

E N

INE

61


1. How does the jet stream affect the global climate?

2. What causes severe weather?

3. Why is air circulation critical to the weather and climate?

Hartmann, Dennis L. Global Physical Climatology. New York: Academic Press, 1994.

Warneck, Peter. Chemistry of the Natural Atmosphere. New York: AcademicPress, 2000.

Ahrens, C. Donald. Meteorology Today With Infotrac: An Introduction to Weather, Climate, and the Environment. London: Thompson International, 2002.

Websites to Visit

1. www.usatoday.com/weather/wstorm0.htm - Comprehensive site detailingweather, its patterns, and effects.

2. www.spc.noaa.gov/climo/reports/yesterday.html - Informative site spon-sored by the National Weather Service detailing current weather trends.

3. www.nws.noaa.gov/ - Official site of the National Weather Service provid-ing a detailed look into weather’s past, present, and future.

4. www.weatherimages.org/data/imag192.html - Interesting interactive siteshowing the jet stream as it moves and changes, and the results.

61

�Consider

Suggested Reading


Websites to Visit


Introduction:

In this lecture we learn about the ocean’s role in the atmosphere.

I. The ocean has an important influence on climate.

A. A phenomenon known as the Gulf Stream carries warm water from theCaribbean up the east coast of the United States. The current turns off-shore near Cape Hatteras and from there it moves across the Atlantictoward northwestern Europe. The current splits as it nears Europe. A por-tion turns north past Ireland, Scotland, and Norway, entering the ArcticOcean. The balance turns south, passing along the coasts of France,Spain, Portugal, and countries in northwest Africa. The current turns westwhen it reaches a latitude of about 20˚ North. The entire system defines acontinuous loop. Oceanographers refer to circulations such as that in theNorth Atlantic as an ocean gyre.

1. The atmosphere is driving this Gulf Stream, that is being pushed in dif-ferent directions. The westerly winds that are blowing across the Atlanticpush the water toward the east on the northern extremity of thiswest/east circulation.

2. On the other side you have the trade winds that are generally from theeast, pushing the water toward the west.

3. So it’s ultimately the wind that is the driving force in pushing the surfaceof the water.

B. Gyres such as those in the North Atlantic can be found in all of the world’smajor oceans. The analogue of the Gulf Stream in the North Pacific, forexample, is known as the Kuroshio Current, which carries warm water fromthe south past the east coast of Japan before turning across the PacificOcean on a track toward western Canada. The Pacific gyre continues with asouthward moving current along the west coasts of Canada and the UnitedStates. Known as the California Current, this current carries cold water fromthe north and is responsible for the relatively mild summer weather and cold

6262


Read Andrew F. Bennett’s Inverse Modeling of the Ocean and theAtmosphere.

Consider this ... 1. How does the ocean affect the weather?

2. What is an ocean gyre and what does it mean?

3. What is the Gulf Stream?

Lecture 10: The Role of the Ocean

LE

CT

UR

E T

EN

ocean water experienced along theCalifornia coast.

1. The gyres circulate in a clockwisesense in the northern hemisphere,counterclockwise in the southern hemi-sphere. The existence of these gyres,and their influence on climate,depends ultimately on the strength anddirection of the prevailing winds. Windsat mid and high latitudes blow general-ly from the west. Winds at low latitudesblow generally from the east (northeastin the northern hemisphere, southeastin the southern hemisphere). We canthink of the gyres as spinning underthe driving influence of these windsblowing from opposite directions onthe high and low latitude edges ofthe gyres.

C. The bulk of the water in the ocean isextremely cold, at temperatures close tozero degrees centigrade. Even at theequator, if you were to probe the ocean asa function of depth, you would find thatwhile temperatures were warm near thesurface, they would decrease precipitouslybelow a depth of a few hundred meters.What is the source of this cold water?Deep water forms exclusively at high lati-tudes. There are two principal regionswhere deep water forms, one in the North

63

OCEAN GYRES

There are two types of circula-tion systems in the oceans. Oneis driven by the wind and isbasically surface circulation.The second is deepwater circu-lation that is driven by the densi-ty (temperature and salinity) ofthe ocean.

About 5% of the total volumeof water in the ocean is subjectto surface water circulation.Surface water circulation isorganized into varying sectors ofcurrents. These currents arecalled gyres.

There are six major gyres inthis circulation system. They arethe North Atlantic, SouthAtlantic, North Pacific, SouthPacific, Indian Ocean, and theWest Wind Drift. The West WindDrift is also called the AntarcticCircumpolar Drift, as it is thecurrent that flows around thecontinent of Antarctica.

63

Illus

trat

ion

©R

ecor

ded

Boo

ks,

LLC

.

Atlantic in the vicinity of Norway, the otherin the Southern Ocean near the coast ofAntarctica.

D. While generally the salt concentrationin the ocean is relatively the same,there are parts of the ocean that aresaltier than others. The density of theMediterranean water is higher than thedensity of the Atlantic water and youcan float more easily in theMediterranean. If you look at the salini-ty distribution of the world’s oceans,you’ll find that on the average, theNorth Atlantic at its surface is the salti-est ocean in the world.

1. Salt buildup occurs as the waterevaporates. In the case of the NorthAtlantic, more water evaporates thanis replaced by runoff or rain. This is alittle surprising as most of the bigrivers that are flowing end up in theAtlantic Ocean. The largest river inthe world, the Amazon, flows into theAtlantic. Based on this, one wouldthink that the salt content would bereduced in the Atlantic Ocean ratherthan the other way around. One ofthe reasons this is the case isbecause it’s very difficult to carrywater vapor from the Pacific to theAtlantic, primarily due to the moun-tain ranges where the water vaporprecipitates as rain or snow, leavingonly dry air to make it to the AtlanticOcean. The other factor has to dowith the mountain geography. InCentral America there aren’t anymountains so you don’t have aninterruption in the flow. In that area,however, the trade winds are blow-ing air from the Atlantic to thePacific. Transversely, water vapormoves easily from the Atlantic to thePacific as there are no mountainranges to inhibit the flow of airacross Eurasia.

2. The salinity of the ocean does havea major effect on the global climate.

64

EL NIÑO

The El Niño effect is some-thing most people worldwideare familiar with. It is the namegiven to an amazing weatherphenomenon that occurs everyfew years.

El Niño forms with the cir-culation of the Pacific Oceanpattern known as the El NiñoSouthern Oscillation. During theEl Niño year, the low-pressurearea normally seen over north-ern Australia is replaced by ahigh-pressure area. Thischange in pressure causes thenormally easterly flow of windto reverse itself and blow in awesterly direction. This allowsfor the transport of warm waterfrom the equator back acrossthe Pacific to accumulate alongthe coastline of South America.The warm water forms a barrieratop the cold water underneathand prevents the supply ofnutrients the fish need for sur-vival in that region. This drasti-cally alters the fishing industry,especially in the countries ofPeru and Ecuador. This warmair and high-pressure areaincreases rainfall and floodingon the eastern side of thePacific as well.

Normally an El Niño eventdevelops at the end of the year.In 1991, an El Niño eventoccurred that persisted until1995. It is possible that the con-tinuing global warming situationcan increase the occurances ofthe El Niño effect and thereforethe poverty-ridden countries inSouth America will be economi-cally altered irrevocably.

64

LE

CT

UR

E T

EN

As that water gets up into the Arctic Ocean with a very high salt con-tent and begins to cool off in winter, the temperature of the waterdepends both on density and salinity. Fresh water as it cools has rela-tively low density compared to salt water when it cools. Salt water isdenser. So the higher the salt content, the denser the water will be,especially as it cools down. In the North Atlantic, as it cools, the sur-face water becomes more dense than the water underneath and even-tually sinks to the bottom. So there is a sink hole operating in the NorthAtlantic somewhere near Norway that is sucking water all the waydown from the Caribbean up to that sink hole. With it comes warmwater, drawing heat to supply this sink hole. The total amount of waterflowing in this situation is far greater than the amount of water flowingin all the rivers all over the world.

a. Deep water forming in the North Atlantic flows south, passingaround Antarctica where it is joined by an additional contributionfrom water sinking notably in the Weddle Sea. Deep water from theAtlantic enters the Pacific and Indian Oceans before eventuallyslowly returning to the surface. The circulation loop that began withwater sinking from the surface in the North Atlantic is completed bya return flow of water at the surface, defining a giant loop known asthe global Conveyor Belt. It takes water close to a thousand years tocomplete a single loop of the Conveyor Belt.

b. The trade winds set up an important circulation of waters near thesurface in the tropics. Surface water is moved away from theequator by these winds and replaced by water moving up frombelow. Water entering the surface region in the equatorial zonefrom below is generally colder than water that was there previous-ly. This newly formed surface water warms up as it moves awayfrom the equator. The loop is completed by water sinking from thesurface in the subtropics. This shallow circulation loop has an influ-ence comparable to the atmosphere in transporting heat from thetropics to the subtropics.

II. El Niño and La Niña Pheonoma

A. These two changes in the weather of the tropics have far-reaching effectsfrom where they are immediately felt. In Indonesia, during the normal cold

65

LA NIÑA

Coupled with El Niño, La Niña is a distinct weather pattern of its own, bringingincreased precipitation to western regions of the tropical Pacific with dry condi-tions to the east.

Usually following the El Niño event, La Niña events can be very powerful anddestructive. When the easterly winds become increasingly strong and cause aninordinate amount of cold water to settle in the central and eastern Pacific alongthe equator, global weather patterns are altered significantly.

The world’s oceans absorb the heat that drives the global climate becausethey have the ability to cool or heat the atmosphere above.

65

66

phase there is all this warm water near Indonesia, and it typically rains alot. Rain forests are the dominant form of vegetation in that environment.When you shift into the El Niño phase, the rain actually shifts away fromIndonesia and it moves into the middle of the Pacific Ocean. OverIndonesia, the air is sinking and it gets very dry. When these forests dryout is often when you have very serious fires. Sometimes fires, scientistsbelieve, have been illegally set to clear land that could then be used forsomething else.

B. The other widespread effect of El Niño can be seen as far as the otherside of the South American continent. Often you will have very dry condi-tions in other parts (i.e., Northeast Brazil). You can also see these effectsas far away as Africa. This represents a dramatic change in rainfall pat-terns. In regions where people depend on rainfall agriculture, this can be avery serious problem indeed.

Conclusion:

The atmosphere and ocean play comparable roles in determining the state of theglobal climate system. A model for climate, either past or future, must treat bothatmosphere and ocean as a coupled system. The state of the ocean depends onthe state of the atmosphere and vice versa. Modeling the atmosphere and theocean as a coupled system defines a challenge of daunting complexity, chal-lenging capabilities of even the largest computers available.

66

©N

AS

A

LE

CT

UR

E T

EN

Satellite photo of hurricane storms resulting from the El Niño phenome-non in 1998—a record-breaking season for this weather pattern. TheAtlantic hurricane season got off to an early start, and changes inupper-level winds over the Atlantic have made conditions ideal for hur-ricane formation. Conditions were favorable to generate tropicaldepressions like clockwork every three or four days.

67


1. What is the El Niño phenomenon?

2. How do the oceans contribute to the climate?

3. Are all weather patterns bad?

Suggested ReadingBennett, Andrew F. Inverse Modeling of the Ocean and the Atmosphere.

New York: Cambridge University Press, 2002.

Gill, Adrian E. Atmosphere-Ocean Dynamics. New York: Academic Press, 1982.

National Research Council. From Monsoons to Microbes: Understanding theOcean’s Role in Human Health. New York: National Academic Press, 1999.

1. www.nationalacademies.org/opus/ - Official website for the NationalAcademy of Sciences with a superb presentation of global weather.

2. www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ - Officialwebsite of the National Weather Service devoted to El Niño and La Niña.

3. www.glacier.rice.edu/4_windcirculation.html - Comprehensive websitedescribing the ocean currents and wind circulation.

4. www.epa.gov/OWOW/oceans/ - Excellent website sponsored by theEnvironmental Protection Agency that gives an in-depth view of the rolethe ocean plays in the atmosphere.

�Consider

Suggested Reading


Websites to Visit


Introduction:

In this lecture, we focus on determining climate changes in the past.

I. Earth’s Temperature History

A. We live today at a relatively warm period in Earth’s history. For much of thepast million years or so, the Earth has been cold, subject to what we referto as ice ages interrupted by relatively brief warm epochs known as inter-glacials.

II. Ice Ages

A. An ice age is a condition in which an ice sheet slowly builds in a few placeson the Earth. It builds notably in North America and in northern Europe.Over a long period of time, the ice sheet advances and it thickens until itreaches its maximum extent. Even in the middle of summer the ice sheetwould be several kilometers thick. The wind blowing across the ice sheetwould be bitterly cold.

B. The last ice age reached its peak about 20,000 years ago. At that time,much of North America, down to the latitude of about New York, was blan-keted in a thick layer of ice. Conditions, even at the peak of summer as farsouth as New York, would have been bitterly cold as icy winds blew acrossthis frozen landscape. An ice sheet also blanketed large parts of northwest-ern Europe. Sea level globally was about 120 meters lower than today, aconsequence of the vast amount of water stored in these extensive land-based ice sheets. Even the continents reformed during this period. Forexample, during the ice age, Asia was connected to North America. This,remember, allowed the first humans to arrive in North America.

C. The expansion and retreat of the ice sheets are thought to be controlledultimately by subtle changes in the orbital parameters of the Earth. Today,we are at about the midpoint of the range. The tilt angle of the axis aboutwhich the Earth rotates is about 23.5˚, heading toward a minimum value ofabout 22˚ from a maximum of 25˚. When the axis is pointing away from the

6868


Read M.K. Hughes’s The Medieval Warm Period.

Consider this ... 1. How do we know about historical changes in climate?

2. What does the Earth’s rotation have to do with the global climate?

3. What was Antarctica’s role in the historical discovery of climate?

Lecture 11: The History of Climate ChangesL

EC

TU

RE

EL

EV

EN

69

sun in the northern hemisphere, thehighest latitudes are completely dark.There is no daylight. When the axis ispointing toward the sun, then you get24 hours of daylight. This change inthe axis of rotation allows for thechange in seasons.

1. The tilt of the axis of rotation of theEarth bobs up and down through atotal range of about 3˚ relative to avertical axis through the plane onwhich the Earth travels around thesun. This 3˚ bob has a very importantinfluence on the climate of the Earth atleast by modulating the type of sea-sonal changes we would expect. Whenthe tilt is at 25˚ it drags the ArcticCircle down toward the equator.

2. It takes about 41,000 years to com-plete this cycle of the up-and-downrotational axis of the Earth. This isextremely important in determiningthe ice ages and timing of inter-glacial periods.

3. The tilt of the rotation axis plays a criti-cal role in determining the seasonaldistribution of climate. If the rotationaxis was oriented at 90˚ to the orbitalplane, there would be no seasons anddays and nights would be of equallength everywhere on Earth. The tiltcompletes a cycle from high to lowback to high every 41,000 years.

4. The Earth describes an elliptical orbiton its path around the sun. Earth isslightly closer to the sun today duringnorthern winter (December) than it isin northern summer (June). Eleventhousand years from now the situationwill be reversed and in a further11,000 years we will be back to wherewe are today. Scientists refer to thisphenomenon as the precession of theequinoxes. A complete cycle of pre-cession takes 22,000 years. The sea-sons modulate accordingly.

5. There is a third orbital change thataffects the amount of sunlight received

MILUTIN MILANKOVITCH

Milutin Milankovitch (1879-1958) was a Serbian mathe-matician who devoted the wholeof his career to developing amathematical theory of climatebased on seasonal and solarchanges received by the Earth.

Milankovitch was born in a ruralvillage in Serbia and attendedthe Vienna Institute ofTechnology, graduating with hisdoctorate in 1904. He accepteda faculty position at theUniversity of Belgrade in 1909and remained there until hisdeath in 1958.

Milankovitch developed a theo-ry, which is named after him,suggesting that as Earth travelsthrough space and around thesun, there are variations in threeelements of Earth-sun geometrythat cause variations in theamount of solar energy reachingthe surface of the planet. Thethree elements were the shapeof the orbit around the sun, thechanges in the angle of axisrotation, and changes in theplane of the Earth’s orbit.

He was the first to describehow ice ages could occur. Hebelieved that in summer, if theamount of sunlight reaching thesouthern edge of the ice sheetis increasing, then the ice sheetwould recede. As the ice sheetrecedes, then you expose dark-colored rock underneath that willbegin to absorb more sunlight.His theory was that as the sunwarmed up the ice sheet, thesecondary effect would be thewarming up of the rock under-neath, which would then drivethe ice further back.

69

at specific latitude at a specific time ofyear. The ellipticity of the Earth’sorbit on its path around the sun isalso subject to change, slowly in this case. It takes about 100,000years to implement a cyclic changein eccentricity from a near-circularpath to a more extended elliptic pathand from there back to a circularconfiguration for the orbit of theEarth around the sun.

6. The impact of these orbital variationsis an irregular but predictable changein sunlight arriving at any given lati-tude at a particular time of year. Theconventional explanation for ice agesand related climate changes involvesfeedbacks triggered by these orbitallyrelated variations in seasonal sun-light. Imagine that the amount of sun-light reaching the southern edge of theice sheet in summer is increasing with time. The idea is that this wouldcause the ice sheet to recede, expos-ing dark rock underneath, thusenhancing the amount of sunlightabsorbed by the surface, forcing fur-ther retreat of the ice sheet.

7. Conversely, if summer sunlight weredecreasing, these conditions wouldfavor an advance of the ice sheet. Myown view is that the sequence of causeand effect is more complicated thanthis, that it involves also importantchanges in the circulation of the ocean,driven at least in part by the orbitallymodulated seasonal changes in sun-light. These changes in circulation, Ihave argued, may arise as a responseto changes in the spatial extent of seaice, most notably in the SouthernOcean, with these changes in sea icearising as the direct effect of thechanges in the seasonal variation ofincident sunlight.

8. Recovery of the Earth from the last iceage began about 19,000 years ago.The ice sheets of the northern hemi-

70

YOUNGER DRYAS

The Younger Dryas was initi-ated, it is thought, by a flood offresh water released into theSaint Lawrence Seaway andfrom there to the North Atlanticwhen an ice dam broke thatpreviously restricted drainage ofa large lake located in glacialtimes to the northwest of thecurrent Great Lakes (referred toby geologists as Lake Agassiz).The Younger Dryas endedwhen this infusion of freshwater was absorbed by theAtlantic and when the salt con-tent of surface water built backto the point where deep waterformation could resume in theNorth Atlantic. Changes in theoperation of the Conveyor Beltwere clearly implicated in theYounger Dryas transition but itis apparent that the adjustmentof the climate was even morecomplex. Large changes intemperature were experiencednot only in the North Atlanticbut also in the tropics. Changesin the tropics may have arisenas a result of changes in theshallow circulation of the tropi-cal Pacific.

70

LE

CT

UR

E E

LE

VE

N

71

sphere began slowly to recede andsea level rose accordingly. The paceof warming accelerated about 15,000years ago but then abruptly the Earthreturned to frigid ice age temperatures.The cold snap began about 13,000years ago and lasted about 2,000years. Climate scientists refer to thisepisode as the Younger Dryas climatereversal. A growing body of evidencesuggests that it was global in extent. Itended in less than a decade or so.Worrying about climate change in thepresent context, the story of theYounger Dryas is instructive. It sug-gests that changes in global climatecan occur abruptly. Those who believethat future changes will necessarilyoccur slowly may be flying in the faceof history.

9. Warming resumed following the end ofthe Younger Dryas epoch. Global tem-peratures reached a maximum about6,000 years ago. Since then, at leastuntil recently, the Earth has been cool-ing off on its way, one might think, tothe next ice age. The general coolingwas punctuated for periods of a fewhundred years when the Earth waseither slightly warmer or colder thanthe long-term average. One of thewarmest periods in recent history iscalled the Medieval Optimum, in whichthe Vikings went into the North AtlanticOcean to explore in relative safety andin smaller boats. This allowed for theVikings’ colonization of Greenland. Themost recent cold snap, known as theLittle Ice Age, began about 700 yearsago and ended at about the same timeas the onset of the rise in CO2

observed to begin in the latter half ofthe 18th century.

D. Was it coincidence that the Little Ice Ageended with the rise in CO2? This is animportant question. If the Earth wasready to warm up anyway, then skepticscould argue that the additional warmingobserved in the present century simply

MEDIEVAL OPTIMUM

From the 10th to the 13thcentury the Earth experiencedan unusual warm period thatpreceded the last ice age.During this time, grapes couldbe grown in Europe 300 milesnorth of where they can begrown today. The Vikings alsotook advantage of the ice-freenorth seas to colonizeGreenland.

Global temperatures werethought to be only a fewdegrees higher than in the pre-vious global period. However,this affected primarily the farnorthern hemisphere of NorthAmerica and northern Europe.It also happened that duringthis period of warming, afamous Viking, Eric the Red,was able to leave his home inIceland and settle the island ofGreenland. Exiled from hishome, Eric set sail toward thewest to find an island that fel-low Icelanders often spoke ofbut knew little about. He sailedaround the southern coast ofGreenland until he found anarea with a deep, warm fjordand settled there. He called theisland Greenland, believing thata beautiful name would drawthe attention of other settlers.Before the year 1300, shipsregularly sailed from Norwayand other European countriesto Greenland.

71

may be part of a natural fluctuation. The question underscores the impor-tance of context and the need to understand the factors responsible for nat-ural variability of climate.

7272

ICE AGES

When most people hear the term ice age, they automatically conjureup a notion of the entire planet encased in a sheet of ice, where ani-mals and humans alike dwell in ice castles and feed off each other forsurvival. This is only partially true.

Ice ages are indeed periods of time when large areas of the Earth arecovered with ice sheets or glaciers. Ice ages normally refer to longperiods in history when the size of the global glaciers extended orreceded for many years. These periods could have lasted from tens tohundreds of millions of years. Generally scientists have broken up thefour major ice ages in particular time periods.

The Proterozoic Ice Age was the first ice age and occurred between800 and 600 million years ago. The Proterozoic was followed by theOrdovician and Silurian at 460 to 430 million years ago, thePennsylvanian and Permian Ice Age at 350 to 250 million years ago,and the Neogene to Quatenary Ice Age at 4 million years ago.

Scientists have discovered that ice ages don’t just suddenly happenbut appear to be the culmination of longer periods of global climaticcooling that took place tens of millions of years before the start of theice age. This resulted in the “growth” of the glacier. As the climate con-tinued to cool it caused the glacier to begin spreading. Because icereflects sunlight back into the atmosphere the surface of the Earthremained colder and therefore allowed for further growth of the icesheet. One thing to note with regard to this, the continents were not inthe familiar form that we know of today. It has been suggested that mil-lions of years ago the Earth was formed of water and one land masscalled Pangea. This land mass existed at very high latitude. Reducedconcentrations of CO2 in the atmosphere are also a contributing factorfor an ice age. Since CO2 is a greenhouse gas and partially responsiblefor maintaining the global temperature of the Earth, an absence of or decrease in CO2 concentration would cause the global temperatureto decrease.

LE

CT

UR

E E

LE

VE

N

7373


1. What was the Medieval Warm Period?

2. What was the Younger Dryas?

3. How does the Earth’s rotation affect climate?

Dawson, Alastair G. Ice Age Earth: Late Quaternary Geology and Climate. New York: Routledge, 1992.

Hughes, M. K. The Medieval Warm Period. New York: Kluwer Academic Publishers, 1994.

Troelstra, S.R. et al. The Younger Dryas. Netherlands: Royal Netherlands Academy of Arts and Sciences, 1996.

Websites to Visit 1. http://earth.agu.org/revgeophys/mayews01/node5.html - Interesting look at

the medieval warm period.

2. www.co2science.org/journal/2001/v4n50c1.htm - Official site for theCenter for the Study of Carbon Dioxide and Global Change.

3. www.museum.state.il.us/exhibits/ice_ages/ - Sponsored by the IllinoisNatural History museum describing ice ages and why they occur.

4. http://zebu.uoregon.edu/1996/ph123/l13i.html - Excellent look at the iceage periods and overall climate changes based on rotation of the Earth.

�Consider

Suggested Reading


Websites to Visit


Introduction:

Here we study the contemporary changes in climate and future prospects.

I. Surface Temperature

A. Globally averaged values of surface temperature have risen by about onedegree centigrade over the past 150 years. This increase did not developat a uniform rate. It was confined largely to two periods, from about 1910 to1940 and to the most recent interval from 1970 to the present.

II. Using Models to Determine Climate

A. The ability of models to reproduce trends in climate observed over the past150 years is now considered an important test of the credibility of modelswith respect to their ability to predict the future. Reproducing the past 150years, however, is no easy task. It is necessary to account for the complexinteractions between the atmosphere and ocean and for the hydrologicalcycle, the complex processes responsible for evaporation, clouds, rain, andsnow, and for the retention of moisture in soils and for runoff of water torivers and eventually to the ocean. We need to account for the formation ofsea ice and for the cracks known as leads that have an important influenceon transfer of heat from the underlying ocean to the atmosphere.

1. First attempts to account for the trend in globally averaged surface tem-perature observed over the past 150 years were unsuccessful. Modelsallowing solely for the influence of the rise in the concentration of green-house gases suggested an increase in globally averaged temperaturegreater than that observed. It was recognized at this point that therewere other factors that must be considered, notably the possible influ-ence of sulfur dioxide emitted as a by-product of the combustion of coaland oil. Sulfur dioxide is transformed in the atmosphere to particulatesulfate. Sulfate particles are white in color and consequently have theproperty that they can reflect sunlight, offsetting thus at least part of thewarming effect of the increase in greenhouse gases. Accounting for theinfluence of sulfur and allowing for variability in the output of energy from

7474


Read Eugenia Kalney’s Atmospheric Modeling, Data Assimilation and Predictability.

Consider this ... 1. What is weather modeling?

2. How important a role in weather prediction is weather modeling?

3. How is weather monitored globally?

Lecture 12: Weather ModelingL

EC

TU

RE

TW

EL

VE

75

the sun led to a significant improve-ment in the agreement between mod-els and observation. Questions, howev-er, remain. In particular, we need toaccount not only for reflective particlessuch as sulfate, but also for black sootyparticles produced also by combustion.It is clear that further work must be donebefore we can be fully confident in theability of models either to reproduce thepast or to provide a credible vision forthe future.

2. There is currently a brown cloud overAsia that extends over the IndianOcean. Coal burning, forest fires, andburning using wood fuels, plant fuels,and even animal waste are feedingthis cloud. This brown cloud is cuttingdown on the amount of sunlight that isgetting to the Indian Ocean and affect-ing the health of the people that live inthat area. Some say this brown cloudhas had a significant impact on theflooding in China in recent years. Ithas essentially altered the pattern ofthe Asian monsoon.

B. Despite difficulties in detail, models are ingeneral agreement as to a number oflikely effects on climate of the increase ingreenhouse gases. There is little dispute,for example, that if we continue to rely onfossil fuels as the primary source of glob-al energy, the Earth is likely to warm sig-nificantly. There is disagreement as tothe magnitude of the globally averagedwarming, however. Estimates range fromas little as 1.4˚ centigrade to as much as5.8˚ centigrade. The increase in tempera-tures over the land will generally exceedthose over the ocean and affect the high-er latitudes significantly. This is due tothe fact that in the winter months, whenno sunlight is getting in but you’vealtered the amount of “insulation” in theatmosphere the summer heat will beretained through the winter months. Thiswill in turn prolong the time it takes tocool down the polar regions. An authori-tative assessment (the Intergovernmental

WEATHER MODELING

Ever wonder where your dailyweather report is generated?Daily weather forecasts start asinitial values taken from variouslocations and entered into theNational Weather Servicesupercomputer. Data from satel-lite, radar, and balloon observa-tions are assimilated and pro-vide initial conditions for com-puter models of the atmosphere.Unfortunately, these modelshave a high degree of uncer-tainty. Once all of the informa-tion has been input to the supercomputer, a weather model isgenerated and is then read bymeteorologists and eventuallythe information is filtered downto your local forecaster.

Many times, weather predic-tions are inaccurate. Nature andthe global environment form anever-changing beast. Informationwe receive is based on a varietyof assumptions, air pressure,surface temperature, ocean tem-perature, wind velocity, jetstream, and a whole host ofother variables, as we’ve dis-cussed in this lecture. The alter-ation of a single one of theseitems facilitates in altering theentire weather picture as awhole. If, for example, a stormfront was moving at a certainspeed and velocity and the windwere to shift direction, it couldstrengthen, weaken, or move thefront into an entirely separatephase of its existence. At thetime you are presented with theforecast it truly is the best guess.

75

Panel on Climate Control report published in 2001) suggests that tempera-tures are likely to climb globally to values not seen over at least the past10,000 years.

1. Models suggest that the warming is likely to be most pronounced athigh latitudes in winter. This could lead to a significant decrease in sea ice cover at high latitudes and could result potentially in an ice-free Arctic Ocean. There are indications of a significant decrease inthe aerial extent of sea ice in the Arctic, especially in summer, inrecent years.

2. Some of the positive effects of this are that if the Arctic Ocean is icefree, you have a new shipping lane with which to transport goodsacross the globe. One of the negative effects, however, is that Siberiahas a lot of natural resources but getting those products to a markethas been extremely difficult. If the Arctic Ocean is now an open water-way, exploitation of those natural resources could have a seriousimpact on the ecosystem of Siberia. It is likely that the permafrost levelwill decrease with winter warming. If this occurs, then all of the con-struction that has taken place based on this permafrost level is now injeopardy. Another example that arises from this warming trendinvolves the polar bear. The polar bear walks out onto the ice until itfinds a lead and then it catches fish. Without ice, the polar bear has noway of getting to the fish that it eats for survival.

3. The water vapor content of the atmosphere is likely to increase. As aconsequence, when it rains, precipitation is likely to be heavier thantoday, leading to floods in some regions, offset by droughts elsewhere.

C. At least one model suggests that there may be significant changes in cli-mate also in the tropics. The UK Hadley Center model forecasts a shift intropical rainfall patterns, reflecting changes in ocean circulation. It sug-gests that rainfall over the Western Pacific may increase significantly overthe next 50 years, but that drought may be the rule for the Amazon Basinand for parts of equatorial Africa. This change in outflow would create adisturbance in the general circulation of the world’s oceans and wouldconspire to change the current way in which the rain forests work. Theconsequence of this type of change over the Amazon Rainforest would belittle rain where before rain was abundant. The rainforests may disappearin Amazonia to be replaced with dry savanna-type vegetation and temper-atures may climb by as much as 5˚ relative to today.

D. The warmer Earth that we are predicting for the future is likely to holdmore water vapor in the atmosphere. If this warmer Earth holds morehumidity, then evaporation and retention of water vapor should remainconstant. However, since there is more water vapor in the atmosphere,when it does rain, it will rain more. These scenarios are bad for people.

Conclusion:

Predicting overall climate changes is an extremely difficult task based on thelimited abilities of our models and the computer systems that generate them.

7676

LE

CT

UR

E T

WE

LV

E

7777


1. What is weather modeling?

2. Why is global climate change difficult to predict?

3. Think of examples of how wildlife is affected by global climate changes.

Bennett, Andrew F. Inverse Modeling of the Ocean and Atmosphere. New York: Cambridge University Press, 2002.

Kalney, Eugenia. Atmospheric Modeling, Data Assimilation and Predictability. New York: Cambridge University Press, 2002.

Peng, Gongbing. Environmental Modeling and Prediction. London: Springer Verlag, 2001.

1. www.emc.ncep.noaa.gov/gmb/ - Official website for the National Centerfor Environment Prediction.

2. www.ccic.gov/pubs/blue97/acc-weather.html - Official website on weathermodeling including interactive graphics.

3. www.acl.lanl.gov/GrandChal/GCM/gcm.html - Informative site on monitor-ing global weather patterns and changes.

4. http://humbabe.arc.nasa.gov/MGCM.html - Official NASA website devot-ed to weather modeling not only on Earth but on the surrounding plan-ets as well.

�Consider

Suggested Reading


Websites to Visit


Introduction:

In this lecture we will address the policy changes and governmentalresponses to global warming.

I. The Aftermath of the Montreal Protocol

A. Following the implementation of the Montreal Protocol addressing humanimpacts on the abundance of ozone in the stratosphere, the global commu-nity turned its attention to the climate issue. Dealing with climate change isenormously more complex than dealing with ozone. Significantly reducingemission of greenhouse gases will require a major change in the wayhumans use energy. Billions of dollars were at stake in the ozone issue butthe stakes for climate change are measured in trillions.

II. The World Summit

A. The first international initiative to address the climate issue was developedat the World Summit in June 1992. Most of the world’s leaders were pre-sent for this summit. The outcome of this meeting is summarized in a doc-ument known as the United Nations Framework Convention on ClimateChange (FCCC).

1. The following are some of the highlights of the FCCC:

a. It declares that global warming is a serious issue and needs the atten-tion of the world community.

b. It establishes an Intergovernmental Body on Climate Change thatinvolves a number of scientists from around the world to purvey whatwe know about the climate issue.

B. The FCCC makes strong distinctions between the developed and unde-veloped countries. The developed countries are called Annex 1 countries.The Annex 1 countries include the United States, Europe, Japan,Australia, Canada, and the countries of the former Soviet Union.

1. The responsibility of developed countries is to take the lead in reducingemissions of greenhouse gases, to protect the climate system for thebenefit of present and future generations of humankind (“on the basis ofequity and in accordance with their common but differentiated responsi-

7878


Read Swart and Zwerer’s Climate and Energy: The Feasibility of ControllingCO2 Emissions.

Consider this ... 1. What was the outcome of the Montreal Protocol?

2. How have countries fared in reaching emissions goals?

3. What is the Kyoto Protocol?

Lecture 13: Environmental PolicyL

EC

TU

RE

TH

IRT

EE

N

79

bilities and respective capabilities”).The goal was set so that the emissionsof greenhouse gases by 2000 did notexceed emissions from the year 1990.

C. The FCCC also sets up a series ofmeetings known as the Conference ofthe Parties (COPs) to carry forward theagenda of the FCCC.

D. The FCCC went into force as an instru-ment of international law when Portugalbecame the 50th country to ratify it on21 December 1993.

1. It had been ratified earlier by a unani-mous vote of the US Senate, but manypoliticians still fail to recognize that theUS assumed obligations under FCCC.

III. Kyoto Protocol

A. The Kyoto Protocol is an internationaltreaty establishing target levels for thereduction of Greenhouse gases that,once ratified, will bind member coun-tries to meet their commitments. Thetext of the protocol was adopted inDecember 1997 at the third COP ses-sion of the FCCC in Kyoto, Japan.

B. The conditions by which the KyotoProtocol would become international law:

1. More than 55 countries will have to rat-ify the protocol.

2. For the Annex 1 countries, more than55% of their total emissions must beobligated to the protocol before thetreaty will go into effect.

IV. TThhee RReessppoonnssee ooff GGoovveerrnnmmeennttss ttoo tthheeKKyyoottoo PPrroottooccooll

A. The European countries took thisagreement very seriously and immedi-ately began taking measures to adhereto the agreed-upon standards to protectthe ecosystem in Europe.

1. In preparation for Kyoto, the Europeancommunity was arguing for a 16%reduction in greenhouse gas emis-sions relative to 1990 but changed thetarget date to 2008.

EMISSION EXCHANGE

The idea of emissionexchange was first brought tothe table by the United Statesduring the Kyoto Protocol. Thebasic premise of this proposalwas to offer countries that couldnot economically decreasegreenhouse gas emissions theopportunity to purchase green-house gas emission levels fromcountries that were well belowthe level of emissions requiredby the Kyoto Protocol. For themajority of the countries, theUS idea of emission exchangewas largely ignored—until afterthe United States dropped outof the Kyoto negotiations.

Since that time, Europe hasdeveloped a plan to corner the“emission trading” industry.Fueled by the fact that only oneother country needs to ratify theKyoto Protocol for it to becomelaw in over 100 countries, theEuropean market has made theemission exchange big busi-ness. By the year 2005, theEuropean market expects trad-ing to be a multi-billion dollarexchange whereby companiesas well as countries are buyingand selling emission reductionson the commodities market.The idea is that whoever canlower emissions cheaply cansell unused permits, therebycreating a profitable way toincrease pollution reduction.Overall, as the amount of pollu-tion becomes less and less,governments can reduce thenumber of permits available andin doing so keep the price high.

79

80

2. The European leaders formed an alliance and joined forces to reduceemissions of greenhouse gases but allocated that to individual countriesdepending on their ability to meet the obligation.

B. The United States, having increased it’s greenhouse gas emissions over 8%from 1990, found it impossible to meet the suggested terms under the KyotoProtocol. Instead, the United States offered several alternatives such as buy-ing emission allocations from other countries or assisting developing coun-tries with their own reduction of greenhouse gas emissions.

1. Vice President Gore, representing the US at the conference, negotiateda compromise: the flexibility mechanisms were agreed on as well as thefollowing reductions:

a. The Kyoto Protocol identifies specific targets for reduction of green-house gas emissions to be met by a group of developed countriesidentified as Annex 1 countries in the protocol.

b. Under the terms of the protocol, the European Union would be obliged toreduce emissions by 8% relative to 1990 in the period of 2008 to 2012.The United States would reduce by 7% and Japan by 6%. Russia andthe former Soviet Republics would be allowed to keep emissions at the1990 standard, while Australia would be allowed to grow its emissions by8%.

c. The Kyoto Protocol imposes no obligations on developing countries. Italso includes a number of flexibility mechanisms to allow Annex 1 coun-tries to meet their obligations if they are unable to do so by reducingdomestic emissions. These flexibility mechanisms allow for trading ofgreenhouse gas emissions among Annex 1 countries and permits Annex1 countries to receive credit for investments in developing countries.

V. Why the United States Distrusts the Kyoto Protocol

A. By the end of 2002, the emissions from the United States were up by 14%over what they were in 1990. There is no possibility the US could meetthe deadline of 2008 without doing very serious damage to its economy.

B. Due to the happenstance of the 1990s, it’s easier for European countriesand Russia to deal with their obligations under the protocol.

C. The Clinton administration returned from the Kyoto Protocol without anyintention of sending it to the Senate for ratification and simply passed it onto the next administration. The George W. Bush administration refuses tosend it for the following reasons:

1. It will damage the economy of the United States.

2. Developing countries such as China and India have not assumed anyobligations. The United States, however, under the FrameworkConvention agreed that the developed countries had to go first. This is infact a contradiction of the ratified law under the first Bush administration.

D. To date, the Kyoto Protocol has not been submitted to the US Senatefor ratification. The US continues, however, to adhere to its obligationsunder the FCCC.

80

LE

CT

UR

E T

HIR

TE

EN

81

Conclusion:

The Kyoto Protocol represents the most significant global effort ever toaddress a major environmental threat. Most of the developed countries haveapproved the protocol and are working toward meeting the requirements. Ofall the Annex 1 countries, however, 33% of greenhouse gas emissions comefrom the United States. Although the United States continues to refuse to rat-ify the protocol, it seems the remaining Annex 1 countries will join and thisshould be enough to establish the Kyoto Protocol as international law.

81


1. What were the conditions of the Kyoto Protocol?

2. Why did the United States opt for emission exchange rather than reduc-tion?

3. What was so critical about the Annex 1 countries’ support?

Manne, Alan S. and Richard A. Richels. Buying Greenhouse Insurance: The Economic Costs of CO2 Emission Limits. Massachusetts: MIT Press, 1992.

Swart, R.J. and S. Zwerer. Climate and Energy: The Feasibility of ControllingCO2 Emissions. New York: Kluwer Academic Publishers, 1990.

Forsyth, Timothy. Critical Political Ecology: The Politics of Environmental Science. New York: Routledge, 2003.

Websites to Visit 1. http://cdiac.esd.ornl.gov/trends/emis/em_cont.htm - This site provides a

comprehensive look at the global emissions changes.

2. http://unfccc.int/resource/convkp.html - Official website for informationabout the Kyoto Protocol.

3. www.ipcc.ch/ - Official website for the Intergovernmental Panel on ClimateChange.

4. www.unep.org/ozone/montreal.shtml - Official site of the United NationsEnvironmental Programme concerning the Montreal Protocol.

�Consider

Suggested Reading


Websites to Visit


Introduction:

In this lecture we will summarize the climate change issues and the interna-tional policies that are being debated.

I. Summary

A. There is no question at this point that humans are a major global influenceand that this is the first time in the history of the Earth that this has everbeen a factor for the global environment.

B. The human population has grown now to over 6 billion people and it contin-ues to grow.

C. More than 10% of the total area of the Earth is devoted to agriculture. Thehuman race has harnessed the Earth and used it to meet its requirementsand purposes.

D. Humans have freed themselves from energy dependence on localresources and can use fossil fuels and make machines to replace animalsor humans in work production. It’s not surprising that the result from this isglobally increasing CO2.

E. It is also evident that the rise in CO2 is essentially a result of what we aredoing. The human race is undeniably responsible for those changes.

1. Some of these increases are a direct result of our use of naturalresources, coal, fossil fuel, natural gas, deforestation, and our reliance onlarge numbers of domestic animals, which has led to an increase in organ-ic waste.

II. Implications for Climate

A. The probable implication is that the Earth is slowly warming and it isalmost beyond dispute that it will warm to an extent that we haven’t seenfor a long time.

1. The Intergovernmental Body on Climate Change believes that theEarth’s relative temperature is almost back to where it was nearly 5thousand years.

8282

Consider this ... 1. Are we doing enough to eliminate fossil fuel emissions?

2. What are the alternative energy sources?

3. What has prevented the US from ratifying the Kyoto Protocol?


Read Peter Hodgson’s Nuclear Power: Energy and the Environment.

Lecture 14: SummaryL

EC

TU

RE

FO

UR

TE

EN

III. The Likely Effects

A. High latitude winters will get warm.

B. Some regions will benefit and some willsuffer, particularly with regard to agri-culture.

1. Forecasting the winners and losers inthis scenario is very unpredictable.

C. A number of the climate changes haveserious implications. The fate of polarbears, the possibility of microbes migrat-ing to different environments, the spreadof malarial viruses, cholera, etc. all havethe potential to destroy ecosystems.

IV. What Can We Do About These Effects?

A. Cut down on our use of fossil fuels.

B. Conserve our energy sources.

C. Optimize things such as lightbulbs to pro-duce more visible light.

D. Design buildings that are more light andenergy efficient.

E. Significantly improve the fuel efficiency ofautomobiles.

V. Automobiles and Conserving Energy

A. We consume gasoline unnecessarily bydriving the cars we do. Hybrid vehiclesutilize part of the gasoline to generateelectricity, which is then used to drive thecar. In these vehicles, even the energycreated by braking is captured and usedrather than expelled as heat. When youstop a hybrid car, the engine converts toan electric engine and therefore basicallyshuts off, eliminating the production ofCO2. Hybrid technology is currently domi-nated by Japanese car manufacturers.

B. Fuel cells are also a way of generatingelectricity using hydrogen as the fuel.The end product is a harmless gas.

VI. Building Construction and ConservingEnergy

A. Energy usage can and should become amajor concern when architects develop abuilding design. Designing structures for

83

NUCLEAR POWER AS ANALTERNATIVE ENERGY

SOURCE

The development of nuclearenergy made available anothersource of energy. The heat of anuclear reactor can be used toproduce steam, which can thenbe directed through a turbine todrive an electric generator, thepropellers of a large ship, orsome other machine. At the endof the year 2000, there were438 operating nuclear powerreactors worldwide. However,construction and application ofnuclear reactors has beenslowed by controversy over thedangers of the resulting radioac-tive waste and the possibility ofan accident at a nuclear reactoror fuel plant, such as those thatoccurred at Three Mile Island(1979), Chernobyl (1986), andTakaimura, Japan (1999).

As the movement towardnuclear power as an alternativeenergy source sparked the pathto better energy, the concernover nuclear weapons quicklybecame a convincing argumentagainst the development ofnuclear energy. For many peo-ple it is felt that you can’t haveone without the other andtherefore the issue of globalwarming and greenhouse gasemissions is simply an unfortu-nate consequence of life.However, this short-sightedview on nuclear power hasresulted in the failure of manycountries to further develop thisas an energy source.

83

84

more efficient use of natural light andoptimal temperature control will obviouslylead to less dependence on fuels.

VII. Alternate Energy Sources

A. Wind power: harness the energy ofthe wind to make electricity.European countries have been ableto utilize this technology to the fullestdue to the fact that governmentshave provided significant incentivesto develop this technology.

B. Nuclear power does not generate CO2

or contribute to greenhouse gas pro-duction.

Conclusion:

The most important thing to take awayfrom this course is that we are all one.We have the most advanced genetictechniques that clearly demonstrate thatwe are all one species and, although welive in different countries in differentstates of development, we all need tocooperate as one unit to address the cli-mate problem. The climate issue wasNOT created by one country on its own. Itis a world problem and it will require theworld to fix it. The climate issue is impor-tant in its own right, but it’s equally chal-lenging as a model for how we are goingto organize global society to cope with theproblems of the 21st century and beyond.

HYBRID AUTOMOBILES

For years NASA has usedfuel cell technology to generateelectricity and power space-craft. The fuel is fed into anelectrolyte near the electrodesand an electric current is creat-ed. In hydrogen fuel cells, waterand heat are the only by-prod-ucts. Fuel cells offer a cleanalternative not only for electrici-ty generation, but also for pow-ering automobiles and othervehicles. Mercedes-Benz,Honda, and Toyota—to be fol-lowed by a number of automak-ers—are in the process of pro-ducing hydrogen-powered vehi-cles, which use an advancedfuel cell to generate power. Theonly emission as a result of thisis water.

Hybrid automobiles are takingthis technology one step fur-ther. Hybrid means that thevehicle runs on two or moreenergy sources. Current pro-duction centers around vehiclesthat utilize both gasoline andelectricity for operation. A paral-lel hybrid car has a gas tank tosupport the engine as well as abank of batteries that can oper-ate with the gas tank simultane-ously. A series hybrid, however,powers the engine with gaso-line where the engine acts likea generator and powers thetransmission. And emissionsare a lot less.

Hybrid vehicles are the waveof today where fuel-celled vehi-cles are the future.

84

LE

CT

UR

E F

OU

RT

EE

N

8585


1. Are we doing enough to stop global warming?

2. What steps can be taken to safeguard the planet in the future?

3. Are hybrid cars the wave of the future?

Berinstein, Paula. Alternative Energy: Facts, Statistics and Issues. New York: Oryx Press, 2001.

Hodgson, Peter. Nuclear Power: Energy and the Environment. Toronto: Imperial College Press, 1999.

Manwell, J. F. Wind Energy Explained. New York: John Wiley and Sons, 2002.

Websites to Visit 1. www.eere.energy.gov/wind/ - Official government website for the

Department of Energy on wind energy.

2. http://supct.law.cornell.edu/supct/ - Supreme Court Collection maintainedby Cornell Law School. Contains a large electronic collection of decisions.

3. www.soton.ac.uk/~engenvir/environment/alternative/hydropower/energy2.htm - Site differentiates between alternative energy useand application.

4. http://yosemite.epa.gov/OAR/globalwarming.nsf/content/ClimateFutureClimateGlobalTemperature.html?OpenDocument - Official EPA site onclimate future.

�Consider

Suggested Reading


Websites to Visit


86

GLOSSARY OF TERMS

Aerobe: An organism that requires air or free oxygen to maintain its lifeprocesses.

Anaerobe: An organism that does not require air or free oxygen to maintain itslife processes.

Chlorofluorocarbon: (CFC) Any member of a group of substances that is aderivative of methane or ethane with the hydrogen atoms replaced by combina-tions of chlorine and fluorine.

Continental Drift: The concept of continent formation by the fragmentation andmovement of land masses on the surface of the Earth. Also known as continen-tal displacement.

Eukaryote: A superkingdom that includes living and fossil organisms compris-ing all taxonomic groups above the primitive unicellular prokaryotic level.

Glaciation: Alteration of any part of the Earth’s surface by passage of a glacier,chiefly by glacial erosion or deposition.

Greenhouse Effect: The effect created by the Earth’s atmosphere in trapping heatfrom the sun; the atmosphere acts like a greenhouse.

Gulf Stream: A relatively warm, well-defined, swift, relatively narrow, northward-flowing ocean current that originates north of Grand Bahama Island where theFlorida Current and the Antilles Current meet, and which eventually becomesthe eastward-flowing North Atlantic Current.

Jet Stream: A relatively narrow, fast-moving wind current flanked by more slowlymoving currents; observed principally in the zone of prevailing westerlies above thelower troposphere, and in most cases reaching maximum intensity with regard tospeed and concentration near the troposphere.

Messenger Ribonucleic Acid: (mRNA) A linear sequence of nucleotides that istranscribed from and complementary to a single strand of deoxyribonucleic acidand which carries the information for protein synthesis to the ribosomes.

Nebula: Interstellar clouds of gas or small particles.

Neogene: An interval of geologic time incorporating the Miocene and Plioceneof the Tertiary period; the Upper Tertiary.

Ordovician: The second period of the Paleozoic era, above the Cambrian andbelow the Silurian, from approximately 500 million to 440 million years ago.

Ozonosphere: The general stratum of the upper atmosphere in which there isan appreciable ozone concentration and in which ozone plays an important partin the radiative balance of the atmosphere; lies roughly between 6 and 30 milesabove the Earth (10 and 50 kilometers), with maximum ozone concentration atabout 12 to 15 miles (20 to 25 kilometers). Also known as ozone layer.

Pennsylvanian: A division of late Paleozoic geologic time, extending from 320to 280 million years ago, varyingly considered to rank as an independent period

GL

OS

SA

RY

or as an epoch of the Carboniferous period; named for outcrops of coal-bearingrock formations in Pennsylvania.

Permafrost: Perennially frozen ground, occurring wherever the temperatureremains below 0°C for several years, whether the ground is actually consolidat-ed by ice or not and regardless of the nature of the rock and soil particles ofwhich the Earth is composed.

Permian: The last period of geologic time in the Paleozoic era, from 280 to 225million years ago.

Polyatomic Molecules: A species formed by the covalent bonding of atoms oftwo or more different elements, usually nonmetals.

Prokaryote: A primitive nucleus, where the deoxyribonucleic acid-containingregion lacks a limiting membrane. 2. Any cell containing such a nucleus, suchas the bacteria and the blue-green algae.

Proterozoic: Geologic time between the Archean and Paleozoic.

Protozoa: A diverse phylum of eukaryotic microorganisms; the structure variesfrom a simple uninucleate protoplast to colonial forms, the body is either nakedor covered by a test, locomotion is by means of pseudopodia or cilia or flagella,there is a tendency toward universal symmetry in floating species and radialsymmetry in sessile types, and nutrition may be phagotrophic or autotrophic orsaprozoic.

Punctuated Equilibrium: A model of evolution that proposes long periods with-out change punctuated by periods of rapid speciation, with natural selection act-ing on species as well as on individuals. Also known as punctuated evolution.

Quaternary: The second period of the Cenozoic geologic era, following theTertiary, and including the last 2-3 million years.

Rumen: The first chamber of the ruminant stomach.

Ruminant: Characterized by the act of regurgitation and re-chewing of food.

Ruminantia: A suborder of the Artiodactyla including sheep, goats, camels, andother forms, that have a complex stomach and ruminate their food.

Silurian: A period of geologic time of the Paleozoic era, covering a time span ofbetween 430-440 and 395 million years ago.

Solar Nebula: The planets originated from the solar nebula surrounding theproto-sun; as the sun cooled, it contracted, rotated faster, and thus caused aring-like bulging at the equator; this bulge eventually broke off and formed theplanets.

Symbiosis: An interrelationship between two different organisms in which theeffects of that relationship is expressed as being harmful or beneficial.

Tectonic Plate: Any one of the internally rigid crustal blocks of the lithospherethat moves horizontally across the Earth’s surface relative to one another. Alsoknown as crustal plate.

Tectonics: A branch of geology that deals with regional structural and deforma-tional features of the Earth’s crust, including the mutual relations, origin, andhistorical evolution of the features.

87

88

SU

GG

ES

TE

DR

EA

DIN

GSUGGESTED READING

COURSE TEXT:

McElroy, Michael. The Atmospheric Environment: Effects of Human Activity. New Jersey: Princeton University Press, 2002.

OTHER SUGGESTED READING:

Benedict, Richard Elliot. Ozone Diplomacy: New Directions in Safeguarding the Planet. Massachusetts: Harvard University Press, 1998.

Bennett, Andrew F. Inverse Modeling of the Ocean and the Atmosphere. New York: Cambridge University Press, 2002.

Coleman, D and B. Fry. Carbon Isotope Techniques. New York: Academic Press, 1991.

Hartmann, Dennis L. Global Physical Climatology. New York: Academic Press, 1994.

Hodgson, Peter. Nuclear Power: Energy and the Environment. Toronto: Imperial College Press, 1999.

Hughes, M.K. The Medieval Warm Period. New York: Kluwer Academic Publishers, 1994.

Kalney, Eugenia. Atmospheric Modeling, Data Assimilation and Predictability. New York: Cambridge University Press, 2002.

Lane, Nick. Oxygen: The Molecule That Made the World. New York: Oxford University Press, 2003.

National Academy of Sciences. Methane Generation from Human, Animal and Agricultural Wastes. Toronto: Books for Business, 2001.

Moroto-Valer, M. Mercedes et al. Environmental Challenges and Greenhouse Gas Control for Fossil Fuel Utilization in the 21st Century. New York: Plenum Publishing Co., 2002.

Oreskes, Naomi. Plate Tectonics: An Insider’s History of the Modern Theory of the Earth. New York: Westview Press, 2002.

Swart, R.J. and Zwerer, S. Climate and Energy: The Feasibility of ControllingCO2 Emissions. New York: Kluwer Academic Publishers, 1990.

Williams, Michael. Deforesting the Earth: From Pre-history to Global Crisis. Illinois: University of Chicago Press, 2002.

global warming: global threat

Documents