global climate change for beginners robert k. kaufmann july 7, 2008
TRANSCRIPT
Global Climate Change for Beginners Global Climate Change for Beginners
Robert K. Kaufmann
July 7, 2008
http://www.bu.edu/cees/people/faculty/kaufmann/index.html
Surface TemperatureSurface Temperature
Climate vs. WeatherClimate vs. Weather
Weather: Conditions on any given dayTemperature in Boston today is 91oF
Climate: Average conditions on any given day over The average temperature in Richmond on
July 7, is 83oF
15,000 Years of Temperature15,000 Years of Temperature
1000 Years of Temperature1000 Years of Temperature
Instrumental Temperature RecordInstrumental Temperature Record
Heat Balance of Planet EarthHeat Balance of Planet Earth
Changes in Out-Going RadiationChanges in Out-Going Radiation
Radiative Forcing of Sulfur EmissionsRadiative Forcing of Sulfur Emissions
Direct Effect
The Heat Balance of Planet EarthThe Heat Balance of Planet Earth
Ground
SOx
The Heat Balance of Planet EarthThe Heat Balance of Planet Earth
Ground
SOx
Clouds
The Vostok RecordThe Vostok Record
From: Petit et al., Nature 399, 429 - 436 (1999
How Do Humans Affect Radiative How Do Humans Affect Radiative Forcing?Forcing?
Burning Fossil FuelsBurning Fossil Fuels
Changing Land-UseChanging Land-Use
DeforestationChopping down trees releases carbon dioxideIncreasing termite habitat methane emissions
AgricultureRice paddies--human swamps emit methaneLivestock--Methane ‘burps’
Human Sources of Carbon DioxideHuman Sources of Carbon Dioxide
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Fossil Fuel
Deforestation
Humans are Not the Largest Humans are Not the Largest
Source of Carbon Dioxide Source of Carbon Dioxide
http://en.sevenload.com/videos/ha4PoKY/The-Great-Global-Warming-Swindle
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The Global Carbon Cycle The Global Carbon Cycle
Atmospheric ConcentrationsAtmospheric Concentrations
Detection: Is Climate Changing?Detection: Is Climate Changing?
Earlier Springs, Later AutumnsEarlier Springs, Later Autumns
Rising Sea LevelsRising Sea Levels
Figure 5.13
Attribution: Are Humans Responsible Attribution: Are Humans Responsible for Climate Change?for Climate Change?
Model ResultsModel Results
Statistical Analysis of Historical DataStatistical Analysis of Historical Data
How Much How Much Doubt Really Exists?Doubt Really Exists?
“If rising carbon dioxide is the cause of rising temperatures, why didn’t it cause temperatures to rise from 1940 to 1970?
“Trust me, the satellite data have been reanalyzed dozens of times,…they show much less warming than expected by theory
Solar Activity is to BlameSolar Activity is to Blame
http://en.sevenload.com/videos/ha4PoKY/The-Great-Global-Warming-Swindle
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Solar ActivitySolar Activity
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Solar Activity watts/m2 (Lean et al., 1995),
No Relationship Between CarbonNo Relationship Between CarbonDioxide and TemperatureDioxide and Temperature
http://en.sevenload.com/videos/ha4PoKY/The-Great-Global-Warming-Swindle
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are needed to see this picture.
Remember Sulfur Aerosols!Remember Sulfur Aerosols!
Climate Models: How, Where, and By Climate Models: How, Where, and By How Much Will Climate Change?How Much Will Climate Change?
Causes For Temperature ChangeCauses For Temperature Change
Doubling of radiative forcing……………1.2oCIncreased water vapor……….. ……….1.6oCIncrease in clouds………………………..0.8oCChanges in surface albedo……………….0.4oCOther changes……………………………0.2oC
Total change in temperature…………….4.2oC
Climate change impacts on the Climate change impacts on the environment & economyenvironment & economy
Change in sea levelImpact on agricultureImpact on biomesWater Supply
Changes in Sea LevelChanges in Sea Level
Melting of glaciers and polar ice
Thermal expansion of water
Florida 11.8 Thousand Years AgoFlorida 11.8 Thousand Years Ago
Florida 5 Meter Sea Level RiseFlorida 5 Meter Sea Level Rise
Florida 50 Meter Sea Level RiseFlorida 50 Meter Sea Level Rise
Impacts on AgricultureImpacts on Agriculture
Benefits Costs
Longer growing season
CO2 Fertilization
Mid Continent Drying
Warmer nights
Water use efficiency
Can Biomes Migrate in Time?Can Biomes Migrate in Time?
Climate ChangeClimate Change & Extinction& Extinction
Thomas et al, 2004 Nature 427:145-148.
Migration rate Minimum Middle High
Universal dispersal 9-13 15-20 21-32No dispersal 22-31 26-37 38-52
Climate change scenario
By How Much Should Carbon By How Much Should Carbon Emissions Be Reduced?Emissions Be Reduced?
What does society “give up”
What does society gain?
Command & Control Command & Control
BenefitsPoliticians can measure their effectsInvisible taxesReductions known
CostsMay not be least costNo incentive for further reductionsNo incentive for technical developmentCumbersome
Carbon Taxes Carbon Taxes
Tax reflects the marginal damage of carbon emissions
Higher cost reduces emissionsReplace energy use with capital or laborReplace high carbon fuels with low carbon fuels
Tax rate based on carbon content of fuel ($100 ton)Gasoline ($1.00 per gallon) $2.80 per gallonNatural gas ($6.00 per tcf) $12.91 per tcfCoal ($100 per ton) $55 per tonElectricity ($0.11 per Kwh) $0.11 per Kwh
Carbon Taxes Carbon Taxes
AdvantagesLeast cost reductionCost is well knownConstant incentive to reduce emissionsConstant incentive to improve technologyEasy to implement
DisadvantagesReductions are not well knownTaxes Kiss of death
Tradable PermitsTradable Permits
AdvantagesReductions well knownLeast cost reductionConstant incentive to reduce emissionsConstant incentive to improve technologyProven to work well (US sulfur market)
DisadvantagesCost of permit unknownStrong institutionsGood governance
Carbon OffsetsCarbon Offsets
Commercial providersBoston-Nashville round trip 2,043 milesEmissions 1,009 pounds carbon$9.95 in OffsetsOffsets reduce emissions elsewhere