climate change 101. everything i know about climate change i learned at the movies… 200620041995
TRANSCRIPT
Notes• Although the Earth’s atmosphere consists mainly of oxygen and nitrogen, neither plays a
significant role in enhancing the greenhouse effect because both essentially transparent to terrestrial radiation. The greenhouse effect is primarily a function of the concentration of water vapor, carbon dioxide and other trace gases in the atmosphere that absorb the terrestrial radiation leaving the surface of the Earth. Changes in the atmospheric concentrations of these greenhouse gases can alter the balance of energy transfers between the atmosphere, space, land and oceans. A gauge of these changes is called radiative forcing. Holding everything else constant, increases in greenhouse gas concentrations in the atmosphere will produce positive radiative forcing (i.e., a net increase in the absorption of energy by the Earth).
• Water Vapor (H2O) is the most abundant and dominant greenhouse gas in the atmosphere. Water vapor is neither long-lived nor well mixed in the atmosphere, varying spatially from 0 to 2 percent. In addition, atmospheric water can exist in several physical states including gaseous, liquid, and solid. Human activities are not believed to affect directly the average global concentration of water vapor, but, the radiative forcing produced by the increased concentrations of other greenhouse gases may indirectly affect the hydrologic cycle.
• As we will soon see, CO2 is by far the most abundant anthropogenic greenhouse gas, so other gases are set to units equivalent to CO2. What is important to note, however, is that some gases have quite large affects and stay in the atmosphere for long periods of time.
• Sulfur hexafluoride is an insulator used in electrical equipment and switches, carbon tetrafluoride is one of a family of perfluorocarbons mostly emitted from the smelting of aluminum)
CO2 CH4 N2O CF4 SF6
Atmospheric Lifetime (years)
50-200 12 114 >50,000 3,200
Pre-industrial Concentration (ppm)
280 0.722 0.270 40 0
Atmospheric Concentration (ppm)
381 1.774 0.319 80 5.4
Rate of Concentration Change (ppm/yr)
1,610 0.005 0.0007 1.0 (ppt/yr)
0.23 (ppt/yr)
Effects of Different Greenhouse Gases
Source: US EPA: US Greenhouse Gas Inventory Reports 2008http://epa.gov/climatechange/emissions/usinventoryreport.html
Fossil FuelsWorld’s Dominant Energy Source
United States (2005)100 QBtu/yr (1.06e14 MJ)
86% Fossil Energy
World (2005) 462 Quads/yr (4.87e14 MJ)
86% Fossil Energy
World Data from International Energy Outlook 2007 http://www.eia.doe.gov/oiaf/ieo/world.html.U.S. Data from Annual Energy Outlook 2008 http://www.eia.doe.gov/oiaf/aeo/fuel.html
Coal26%Coal26%
Oil37%
Gas23%
Nuclear 6%
Gas23%
Nuclear 8%
Oil41%
Hydro 3%
Renewables (solar, wind, geothermal, biomass) 3%
Renewables 8%
Coal23%Coal23%
Renewables 6%100 Quads
Fossil fuels provide 86% of energy
2005
2030
131 Quads
By 2030, reliance on fossil fuels remains
stable at 86%
Coal23%
Nuclear 8%
Renewables 6%
Oil 41%
Gas23%
Coal26%
Nuclear 7%
Oil 40%
Gas20%
+ 31%
Source: AEO 2007
Energy - USA Energy Requirements
Hydro, 3.0
Biomass, 3.2
Muni Waste, 0.4
Biofuels, 5.1
Geothermal, 0.8
Wind, 1.2
Solar, 0.0
Hydro, 2.7
Biomass, 2.2
Biofuels, 0.6
Muni Waste, 0.4
Geothermal, 0.3
Solar, 0.0
Wind, 0.1
6.3 Quads2005
203013.7 Quads
+ 118%
Source: AEO 2008
Renewable Energy Consumption – Growing Fast BUT from a Small Base
All Fossil Fuels and Energy SectorsContribute CO2 Emissions
Industry29%
Industry29%
Commercial18%
Commercial18%
Residential21%
Transportation32%
Transportation32%
Oil44%Oil
44%
Coal36%Coal36%
Natural Gas20%
AEO2007
United States Carbon Dioxide Emissionsby Source and Sector
CO2 and CH4 - The Primary GHG Contributors
Methane9%
Nitrous Oxide5%
HFCs, PFCs, SF6
2%
CO2 fromEnergy
83%
Other CO2
2%
“EIA Emissions of Greenhouse Gases in the U.S. 2005”
United States Greenhouse Gas Emissions
Equivalent Global Warming Basis
World Carbon Dioxide Emissions By Region, 2001-2025(Million Metric Tons of C Equivalent)
Carbon Intensity By Region, 2001-2025(Metric Tons of C Equivalent per Million $1997)
…But Carbon Dioxide Emissions are growing
Carbon Intensity is falling…
The Budget is DisappearingCumulative Carbon Emissions 1900-2100 (GtC)
Budget for 450 ppm Stabilization
Today
531283
2010
375 439
2020
322492
2030
638 176
2040
809 5
Spent
Remaining
Source: Dave Hawkins, NRDC, presented at Keystone Energy Forum, Feb. 2004
CO2 Concentrations on the Rise(~280 ppm to 370 ppm over last 100 years)
Tem
pera
ture
Cha
nge
from
Pre
sent
(oC
)
Time Before Present (kyr)
CO
2 Con
cent
ratio
n(p
pmv)
200 150 50
350
300
250
200
100 0
2
0
-2
-4
Tatm (Vostok)
CO2 (Vostok)
Possible Harbingers…• Rising sea levels• Spreading disease• Shifting in seasons (e.g., earlier
spring arrival)• Shifting ranges of plant and
animal • Changes in animal and plant
populations• Bleaching of coral reef • Melting permafrost melting• Increased catastrophic weather
(e.g., heavy snowfalls, flooding, ice storms, droughts, fires)
Source: http://www.arctic.noaa.gov and National Climatic Data Center, NOAA
Permafrost and polar ice are melting…