The Greenhouse Effect

SPM 3

Concentration of Carbon Dioxide and Methane Have Risen Greatly Since Pre-Industrial Times

Carbon dioxide: 33% rise Methane: 100% rise

The MetOffice. Hadley Center for Climate Prediction and Research.

BW 5

Variations of the Earth’s surface temperature for the past 140 years

SPM 1a

Variations of the Earth’s surface temperature for the past 1,000 years

SPM 1b

Certainties• Existence of natural greenhouse effect

• Greenhouse gases increasing

• Temperature increasing – 1998 the hottest in at least 1000 years.

• Sea levels rising – 4 -10” over century

Uncertainties

• Timing of atmospheric warming, glaciers

• The effects of increased cloudiness

• Uneven health and ecological impacts

• Unanticipated events

Effects of global warming

People at Risk from a 44 cm sea-level rise by 2080

Assuming 1990s Level of Flood Protection

Source: R. Nicholls, Middlesex University in the U.K. Meteorological Office. 1997. Climate Change and Its Impacts: A Global Perspective.

Sea-level transgression scenarios for Bangladesh

Adapted from Milliman et al. (1989).

Forest fires in drying forests

Percent of USA with above normal proportion of total annual precipitation from -day extreme events (2” +)

Karl et al. 1996

BW 7

Changes in rainfall with doubled CO2

>25.6

Daily rainfall class (mm day–1)

0.2-0.4 0.4-0.8 0.8-1.6 1.6-3.2 3.2-6.4 6.4-12.8 12.8-25.6

160

140

120

80

60

40

20

0

–20

100Change infrequency

(%)

40°N 40°SAustralianlandpoints

Melting of alpine glaciers

Melting of alpine glaciers1941 and 2004

Melting of ice caps

Melting of sea ice,

permafrost

Other impacts• Tropical diseases, insects move north

• Loss of agricultural land

• End of ecosystems that cannot shift

Future goals?

• Reduce CO2 emissions, change economy

• World-wide shift to non-fossil energy

• Increased energy efficiency

29

CO2 emissions per capita

1997 Kyoto Protocol• Cut gases to under 1990 levels by 2012

• China, India exempted for present

• Europeans met most goals

• U.S. would have to cut energy use 40%; Bush withdrew 2001

Energy growth rates

5.5%4.3%

3.2%2.7%

1.5%1.4%

1.1%0.8%

IndiaChinaJapanBrazil

USOECDWorld

Global, 1990-2100

Conservation• Homes

– insulation, less heat, efficient appliances• Vehicles

– Drive less, higher mpg• Industry

– Less waste, renewable and efficient energy• Land use

– More tress (carbon sinks), no sprawl

0

5,000

10,000

15,000

20,000

25,000

1990 2020 2050 2100

SolarHydroBiomassNuclearN. GasCoalOil

Proposal for 2100 energy use

• Renewables (solar, wind, hydro) 50%

• Biomass 30% (5x present use)

• Nuclear phased out

• Fossil fuels 18% (down from 80%)

Mtc

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

1980 2000 2020 2040 2060 2080 2100 2120

CO2 emissions (1990 -2100)

Year

Global energy websitesWorld Resources Institutewww.wri.orgWorld Energy Councilwww.worldenergy.org/World Energy Assessmentwww.undp.org/seed/eap/activities/wea/UN Development Program www.undp.org/seed/eap/