Global Climate / Greenhouse Effect

• What determines the temperature on earth?

• What is the greenhouse effect?

• How can the climate be disturbed?

• What are the consequences of increased

temperatures?

• What is going to happen in the future?

The Equilibrium Temperature of the Earth

41

4)1(

σε−

=Be

es

e

AFT

Te = 255 K = -18°C = -81°F

Variation of Sun-Earth Distance

Eccentricity of Earth’s Orbit

Current N.H.

summer (June)

N N

SS

152 million km 147 million km Current S.H.

summer (January)

11 year cycle of solar radiation11-yr sun spot cycle

Sun spots

The bright regions on the Sun that surround sunspots are called faculae. (Image courtesy Big Bear Solar Observatory) Change of solar

intensity ~0.1% - too weak to be noticed

The Greenhouse Effectno atmosphere

Heat

infr

ared

visi

ble

with atmosphereoutgoing IR radiation is absorbedand emitted back to the ground

Heat

visi

ble

infr

aredEarth IR radiation

Hydrological Cycle

from http://www.watersystems.co.nz/images/hydrologicalcycle.jpg

Carbon Dioxide (CO2)

Source: http://www.esd.ornl.gov/iab/iab2-2.htm

Methane (CH4)Termites Rice Paddies Natural Gas

Leakage

RuminantsWetlands

Nitrous Oxide, N2O“laughing gas”

Biomass burningIndustrial processes

SoilsNitrogen fertilizer

Chloroflourocarbons (CFCs), Hydrofluorocarbons (HCFCs),

Perfluorocarbons (PFCs), Sulfur hexafluoride (SF6)

Aluminum smelting

Refrigeration

Propellant

Insulator for electrical equipment

Tropospheric Ozone (O3)

CO + OH + O2 CO2 + HO2

NO + HO2 NO2

NO2 + hv NO + O

O + O2 O3

Percent Absorption of IR by Greenhouse Gases

Atmosphericwindow

Figure 12.4

Climate HistoryOcean Floor Sediment Analysis

Foraminifera “sea creatures”

GeologicTime Scale

Holocene

Pleistocene

Pliocene

Miocene

Oligocene

Eocene

Paleocene

Cretaceous

Jurassic

Triassic

Tertiary

Quaternary

Devonian

Silurian

Ordovician

Cambrian

Permian

Pennsyl-vanianMissis-sippian

Proterozoic

Archean

0.1

2

5

26

37

53

65

136

190

225

280

320

345

395

430

500

570

2300-2800

4600-4700

Oldest recorded rocks (3800)Earliest recorded life (3500)

First shelled invertebrates (570)

Primitive fish (430-500)

First land plants (395-430)

Coal formation (280-320)

Oxygen-producing photosynthesis (2300)

Formation of Pangea (220)

Meteorite bombardment (4600-4100)

Earliest Eukaryotes (1400)

Era Period Epoch Age(mya)

Antarctic ice (40)

Greenland ice sheet (2.4-4)Arctic sea ice/ Alaskan glaciers (5-6)

Homo habilis (2.0)

Cenozoic

Phanerozoic

Paleozoic

Mesozoic

Precambrian

Age ofmammals

Age ofdinosaurs

Carboniferous

Figure 12.13

Paleocene-Eocene Thermal Maximum

(~55 million years ago)

Rapid warming (10,000 years) lasting 100,000 years

Paleocene-Eocene Thermal Maximum

(~55 million years ago)

Climate HistoryMid-Pliocene (~3.5 million years ago)

Configuration of continents and ocean basins close to present

CO2 concentrations: 360 – 400 ppm

Sea level: 15 – 25 m higher than modern

Global mean temperatures: 2 – 3°C above preindustrial

Estimated mid-Pliocene sea-levelhttp://geochange.er.usgs.gov/pub/sea_level/

The light blue color shows an estimate of the coastline of the eastern United States during the last glacial maximum, about 20,000 years ago. The dark green shows the modern coastline, and the lighter shades of green show the coastlines that may have existed during the warm climatic interval of the middle Pliocene epoch, about 3 million years ago.

Climate HistoryPolar Ice Cores

Limited to ~ 1 million years ago

Antarctica Greenland

Climate HistoryTropical Ice Cores

Prof. Lonnie Thompson –Ohio State University

Climate HistoryTemperature and Greenhouse Gases

Today: CO2 = 370 ppm

CH4 = 1800 ppbPetit et al., 1999

Carbon dioxide (CO2) variability over the past 400,000 years

Proxies for more recent climate variability

Tree Rings Corals

Lake sediment cores

Local temperature variability in the Holocene

Climate HistoryTemperature and Greenhouse Gases

Today: CO2 = 370 ppm

CH4 = 1800 ppbPetit et al., 1999

Reconstructed Temperature over the Past 2,000 Years

Tambora, IndonesiaFrom space shuttle

April 5, 1815 - Moderate eruptionApril 10-11, 1815 - Most powerful eruption in recorded historyTook off 1400 m from the top of the mountain1 billion tonnes of TNT (60,000 atomic bombs)150 times more ash than Mt. St. Helens.82,000 deaths, most local. Reduced temperatures hemispherically by up to 2-3oC for one yearIn Europe and North America, 1816 was “Year without a summer”

Year Without a Summer - 1816Rain, Steam and Speed – The Great

Western Railway

The Fighting Temeraire

Mary Shelley - “Frankenstein”J.M.W Turner (1775-1851)

Instrumental Temperature Record since 1860

Instrumental Temperature Record since 1980

http://www.ncdc.noaa.gov/oa/climate/research/cag3/cag3.html

Recent Temperature Anomalies

compared to Jan. 1940 – Dec. 1980 average

Atmospheric CO2concentrations since 1750

CO2 emissions since 1800

CO2 Balance

Change in CH4(g) Mixing Ratio

0.60.8

11.21.41.61.8

2

1840 1880 1920 1960 2000

CH 4

Year

CH

4(g)

mix

ing

ratio

(ppm

v)

Figure 12.7

Methane Emission (1860-1994)

Figure 12.10, Stern and Kaufman (1998)

1

10

100

1860 1880 1900 1920 1940 1960 1980 2000CH 4

Year

Total

Rice farming

Livestock

Landfills

Gas flaring Gas supply

Coal miningBiomass burning

CH

4(g)

em

issi

ons

(Tg

of m

etha

ne p

er y

r)

Change in N2O(g) Mixing Ratio

Figure 12.7

300

305

310

315

320

1988 1990 1992 1994 1996 1998 2000

N 2

Year

N2O

(g) m

ixin

g ra

tio (p

pbv)

Global Trends in CFCs

Estimated Global Warming Due to Different Gases and Particles

Percent Natural Percent Global Greenhouse Effect Warming

Chemical Due to Chemical Due to ChemicalH2O(g) 88.9 0CO2 (g) 7.5 46.6CH4(g) 0.5 14.0O3(g) 1.1 11.9N2O(g) 1.5 4.2CFCL3(g) 0 1.8CF2Cl2(g) 0 4.2CF2ClH(g) 0 0.6

Table 12.3

Positive Feedback“Runaway climate”

Cause Effect

enhance

0

20

40

60

80

100

120

-20 -10 0 10 20 30 40 50Temperature (oC)

Over liquidwater

Vap

or p

ress

ure

(mb)

0

20

40

60

80

100

120

-20 -10 0 10 20 30 40 50Temperature (oC)

Over liquidwater

Vap

or p

ress

ure

(mb)

Vap

or p

ress

ure

(mb)

Example:

Water vapor

(greenhouse gas)

Negative FeedbackCause Effect

“self-regulation”

suppress

Example:

Low clouds

(reflect visible light to space)

Influence of Clouds

cooling

albedothermalradiation

Negative Feedback: Low Clouds (warm and dense)

→ high albedo⇒ block off solar radiation

→ warm⇒ emit IR radiation at the

temp. of the cloud top

⇒ planetary cooling

Low Clouds

Influence of CloudsPositive Feedback:

High Clouds (cold and thin)

warming

albedothermalradiation → small albedo

⇒ solar radiation is only weakly reflected

→ cold⇒ emit less IR radiation

at the their top

⇒ planetary warming

High Clouds

Permafrost – CH4 hydratesPositive Feedback

Location of sedimentary basins in the Northern Hemisphere that may

contain gas hydrate.Source: Collett and Dallimore, 2000.

Permafrost and gas hydrates are commonly found together

http://whyfiles.org/119nat_gas/5.html

Marine Phytoplankton DMS Sulfate Aerosol

Negative Feedback

Melting Glaciers

Glacier Ururashraju,Peru in 1986

1999Glacier retreated around 500m

Glacier National Park - 1911

2000

Mt. Kilimanjaro Ice Area

Island of Fualopa, Tuvulu

Highest point is 4 m above sea level

Many people on Tuvalu are now looking at migrating; indeed New Zealand has offered to take in 75 Tuvaluans every year.

Extreme Weather Events

Human Health - Malaria

Prediction of Malaria Transmission rates in 2002 relative to theaverage risks between 1961-1990

Epstein, 2000

Percent World CO2(g) Emissions by Country or Continent (1997)

Oceania (5.0)

China (13.9)

Russia (5.9)

Japan (4.8)

India (4.2)

Germany (3.4)

Africa (3.3)

Central+South America (5.5)

U.K. (2.2)Canada (2.0)

Italy (1.7)

Other (19.6)

U.S. (22.6)

South Korea (1.8)

Poland (1.4) France (1.4)Australia (1.3)

Figure 12.22

Per Capita and National Emissions of Carbon (C) in CO2(g) in 1997

Figure 12.230 5 10 15 20

QatarUnited Arab Emirates

KuwaitSingapore

United StatesAustralia

CanadaSaudi Arabia

Czech RepublicNorth Korea

DenmarkNetherlands

BelgiumGermany

RussiaSouth Korea

JapanPolandTaiwan

United Kingdom

Bar 1: National emissions (hundred-million tons of C per year)Bar 2: Per capita emissions (tons of C per person per year)

UNFCCC nations

http://en.wikipedia.org/wiki/Image:UNFCCCcountries.png

Green: UNFCCC member

Peach: UNFCCC observer

Gray: not party to the UNFCCC

Percent Change in 1990 Emissions Required Under

Kyoto ProtocolPercent Change

Country in EmissionSwitzerland, central Europe, European Union -8United States -7Canada, Hungary, Japan, Poland -6Russia, New Zealand, Ukraine 0Norway +1Australia +8Iceland +10

Table 12.5

Kyoto: Country by country

Asia Pacific Partnership on Clean Development and

ClimateJuly 28, 2005