Introduction to Global WarmingIntroduction to Global Warming

Jagadish ShuklaJagadish Shukla

Lecture 1, 31 Aug 2010

CLIM 101: Global Warming: Weather, Climate and Society

OutlineOutlineIntroduction to Global WarmingIntroduction to Global Warming

1.1. What is Global Warming?What is Global Warming?

2.2. What is Greenhouse Effect?What is Greenhouse Effect?

3.3. Observed Changes in ClimateObserved Changes in Climate

4.4. Observed Changes in Greenhouse Gases (GHG)Observed Changes in Greenhouse Gases (GHG)

5.5. Hypothesis: Increases in GHG cause Global WarmingHypothesis: Increases in GHG cause Global Warming

6.6. Testing hypothesis: IPCCTesting hypothesis: IPCC

7.7. Projections of Climate ChangeProjections of Climate Change

8.8. Global Carbon Dioxide (COGlobal Carbon Dioxide (CO22) Emissions) Emissions

9.9. Adaptation, Mitigation and Geo-engineeringAdaptation, Mitigation and Geo-engineering

10.10. Ethics of Climate Change Ethics of Climate Change

11.11. Sustainable Development Sustainable Development

12.12. The Global ChallengeThe Global Challenge

Global WarmingGlobal WarmingGlobal Warming is the increase in the average temperature of the Earth’s near surface air and oceans since the mid-20th century and its projected continuation. (Wikipedia)

0.76°C (1.4°F) since 1900

0.55°C (1.0°F) since 1979

Global Temperature Change (oC)

Annual Mean5-year Mean

Global Mean TemperatureGlobal Mean Temperature

Trend 1901-2005

Trend 1979-2005

Linear trend of Linear trend of annual mean annual mean temperaturestemperatures

• If there were no greenhouse gases the Earth’s temperature would be about 0F (not 59F)

•Greenhouse effect is real; without it, the Earth would be uninhabitable.

• Feedbacks amplify the warming by greenhouse gases.

The Greenhouse EffectThe Greenhouse Effect(The Cause of Global Warming)

Center of Ocean-Land-Center of Ocean-Land-Atmosphere studiesAtmosphere studies

Center of Ocean-Land-Center of Ocean-Land-Atmosphere studiesAtmosphere studies

A Tale of Three Planets

Mars: Mars: −63−63ooCC

Earth: Earth: 1515ooC C (59(59ooF)F)

Venus: Venus: 464464ooCC

Surface Temperatu

re

MARSSun Distance = 1.56

AUF = 592 W/m2

Albedo = 17%Tsfc = 210 K

EARTHSun Distance = 1.00

AUF = 1367 W/m2

Albedo = 30%Tsfc = 288 K

VENUSSun Distance = 0.72 AU

F = 2639 W/m2

Albedo = 78%Tsfc = 737 K

• If there were no greenhouse gases the Earth’s temperature would be about 0F (not 59F)

•Greenhouse effect is real; without it, the Earth would be uninhabitable.

• Feedbacks amplify the warming by greenhouse gases.

The Greenhouse EffectThe Greenhouse Effect(The Cause of Global Warming)

1

Let us look at Let us look at the Observations.the Observations.

Global Mean TemperatureGlobal Mean Temperature

Sea Level Rise over the Last CenturySea Level Rise over the Last Century

thermal expansion added freshwater (melting)

(Himalayas)

Arctic Sea Ice is DisappearingArctic Sea Ice is Disappearing

2007: 38% below average2008: 34% below average

Arctic Sea Ice is DisappearingArctic Sea Ice is Disappearing

Rising Temperature in Chesapeake Rising Temperature in Chesapeake BayBay

Let us look at Let us look at the Greenhouse Gases.the Greenhouse Gases.

WarmingWarming

1. Greenhouse gases (CO1. Greenhouse gases (CO22, CH, CH44, N, N22O)O)• CO2: Carbon Dioxide : Emission from fossil fuel• CH4: Methane : Agriculture• N2O: Nitrous Oxide

2. Land use change2. Land use change

CoolingCooling

1.1. AerosolsAerosols• Man made/Natural• Volcanoes

※※Rate of increase of GHG is largest in 10,000 yearsRate of increase of GHG is largest in 10,000 years

(Net) Global Warming (Net) Global Warming

Evidence for Human-induced Changes in Evidence for Human-induced Changes in GHGsGHGs

(Overwhelmingly convincing!)(Overwhelmingly convincing!)

※Rate of increase of GHG is largest in 10,000 years

Monthly Mean Carbon DioxideMonthly Mean Carbon DioxideNOAA CMDL Carbon Cycle Greenhouse GasesNOAA CMDL Carbon Cycle Greenhouse Gases

Atmospheric carbon dioxide mixing ratios determined from the continuous monitoring programs at the 4 NOAA CMDL baseline observations. Principal investigator: Dr. Pieter Tans. NOAA CMDL Carbon Cycle Greenhouse Gases. Boulder, Colorado. (303) 497-6678

Degrees Celsius above or below30-year average global temperature

An Elegant Science Question: An Elegant Science Question: Are increases in greenhouse gases responsible for

increase in global mean temperature (global warming)?

395

365

335

305

275

14.6

14.4

14.0

13.8

13.4

14.2

13.6

Global Temperature & Carbon Dioxide 1860-2008

• Greenhouse gases increase due to human activities.

• Global warming is due to increases in greenhouse gases.

• Global warming is due to human activities.

HypothesisHypothesis

Alternative HypothesisAlternative Hypothesis

• Global warming is due to natural variations of climate.

How do you test such hypotheses?

Climate Models; IPCC

• Equations of motions and laws of thermodynamics to predict rate of change of:

T, P, V, q, etc. (A, O, L, CO2, etc.)

• 10 Million Equations: 100,000 Points × 100 Levels × 10 Variables

• With Time Steps of: ~ 10 Minutes

• Use Supercomputers

What is a Climate Model?What is a Climate Model?

IPCC has been established by WMO and UNEP to assess scientific, IPCC has been established by WMO and UNEP to assess scientific, technical and socio- economic information relevant for the technical and socio- economic information relevant for the understanding of climate change, its potential impacts and options for understanding of climate change, its potential impacts and options for adaptation and mitigation.adaptation and mitigation.

IPCC has been established by WMO and UNEP to assess scientific, IPCC has been established by WMO and UNEP to assess scientific, technical and socio- economic information relevant for the technical and socio- economic information relevant for the understanding of climate change, its potential impacts and options for understanding of climate change, its potential impacts and options for adaptation and mitigation.adaptation and mitigation.

Intergovernmental Panel Intergovernmental Panel on Climate Change (IPCC) on Climate Change (IPCC)

Working Group I: The Physical Science Basis

Working Group II: Impacts, Adaptation and Vulnerability

Working Group III: Mitigation of Climate Change

• Largest number of U.S. scientists: nominated by the U.S. Govt.

• Highest skepticism : “U.S. Govt.”

Projection of Global WarmingProjection of Global WarmingMean of 15 Models Surface Air Temperature Mean of 15 Models Surface Air Temperature

DifferenceDifference(Sresa1b YR 71-100) minus (20c3m 1969-98), Global Average = (Sresa1b YR 71-100) minus (20c3m 1969-98), Global Average = 2.612.61

IPCC 2007

1.0º C1.0º C

Increase in Surface TemperatureIncrease in Surface Temperature

ObservationsPredictions with Anthropogenic/Natural forcingsPredictions with Natrual forcings

Observed & Projected Global Mean WarmingObserved & Projected Global Mean Warming

GGlobal lobal MMean ean SSea ea LLevelevel

RRelative to the 19elative to the 198080 to to 19991999 mean mean

ImpactsImpacts

Mohamed Nasheed President of the Maldives

WANTED: New Home for My CountryWANTED: New Home for My Country

Number of Days Over 100ºF

Increases in very high temperatures Increases in very high temperatures will have wide-ranging effects.will have wide-ranging effects.

Recent Past, 1961-1979

Higher Emissions Scenario, 2080-2099

Lower Emissions Scenario, 2080-2099

Global Warming in VirginiaGlobal Warming in Virginia

3oCelcius warmer

Between 0% to 10% more precipitation

Annual

Summary of Major ImpactsSummary of Major Impacts

• Heat waves; Droughts; Forest fires

• Coastal area’s habitability (sea level)

• Health (cholera; malaria; dengue; lyme)

• Biodiversity: extinction of species

• Agriculture (uneven); Tropics (serious)

• Water (drying; snow melt; glacier melt)

1. Ignoring climate change will damage economic growth. (The poorest countries and people will suffer earliest and most.)

2. The damage will be on a scale similar to those associated with the great wars and the economic depression.

3. It will be difficult or impossible to reverse changes.

4. The earlier effective action is taken, the less costly it will be.

STERN REVIEW: STERN REVIEW: The Economics of Climate ChangeThe Economics of Climate Change

• Damages from business-as-usual scenario would be at least 5% and up to 20% of Global GDP a year

• Costs of removing most of the climate risk are around 1% of GDP per year

• This is equivalent to paying on average 1% more for what we buy

• “We can grow and be green”

Sir Nicholas Stern

STERN REVIEW: STERN REVIEW: Main threat to a sustainable EarthMain threat to a sustainable Earth

What We Can DoWhat We Can Do

Let us look at the emissionsLet us look at the emissions

Global COGlobal CO22 Emissions Emissions

• In 2005, global emissions were 27 billion tons of CO2

• Per capita, emission (27/6.7 billions) = 4 tons/per capita/yr

• US emissions = 20 tons/per capita/yr

What is 4 tons of COWhat is 4 tons of CO22 per per year?year?• Drive 10,000 miles per year with a car that gives 30 miles

per gallon.

• Fly 10,000 miles per year.

• 300 KWH per month of electricity from coal fired plant.

• 600 KWH per month of electricity from natural gas fired plant.

(my house: 580 KWH in Mar. 2008; 380 KWH in Mar. 2009)

Center of Ocean-Land-Atmosphere studies

• “Polluter must pay”(We (US) are the biggest polluters but we also have the biggest guns.)

• Those who have contributed the least to global warming will suffer the most and the earliest.

• Poor countries would like to improve the quality of life of their people (consume more energy).

• Sustainable developement in a changing climate is challenged by population growth and exetreme poverty.

Ethics of Global WarmingEthics of Global Warming

What We Can DoWhat We Can Do

• Immediate action on conservation and energy efficiencyImmediate action on conservation and energy efficiency• Help elect enlightened leaders and policymakersHelp elect enlightened leaders and policymakers

• Educate the publicEducate the public• Social, economic, scientific, technological researchSocial, economic, scientific, technological research• Create new institutionsCreate new institutions

• International dialogues and negotiationsInternational dialogues and negotiations• Tax; Cap and TradeTax; Cap and Trade

(Individuals; (Individuals; InstitutionsInstitutions; ; GovernmentsGovernments))

• Provide food (and good life) to 9 billion people.

• Reduce odds of catastrophic impacts.

• No magic bullet (push on all fronts).

• Must reduce demand of CO2 (put a price).

• Cost in GDP ‘small’ but how to distribute?

• US must lead.

• Roles of Govts, Industry, Civil society

Challenges and Challenges and OpportunitiesOpportunities

Our Common FutureOur Common Future

Sustainable DevelopmentSustainable Development

“The balance of economic growth, social

justice, and environmental health that

meets the needs of present generation

and enables future generations to meet

their needs.”Our Common Future (1987)

The Brundtland Report

World PopulationWorld PopulationWorld Population from AD 1 to 2002

Source: Data from Maddison (2001), Calculated using data from Maddison (2002)

World Income from 1500 to 2001

World Income per Capita from 1500 to 2001

Since 1750, population increased 10 times; Production per person also increased 10 times; Therefore, total world economic production increased 100 times.

Therefore, the impact of human activity on life-sustaining system on earth increased enormously.

Planet under StressPlanet under Stress

‘Common Wealth’ by Jeffrey Sachs, 2008

Global PovertyGlobal Poverty

‘Common Wealth’ by Jeffrey Sachs, 2008

From 1820 to 1992

Global Well-Being (sustainability, security

and the future of civilization)

The Global ChallengeThe Global Challenge

Inequality and Extreme Poverty

Human PopulationGrowth

EnvironmentalDegradation

YesYes

Managing planet Earth……Managing planet Earth……

A new phase in human A new phase in human historyhistory

An enormous challenge……An enormous challenge……

Are we up to Are we up to it?it?

THANK YOU!

THANK YOU!

ANY QUESTIONS?