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GLOBAL PROJECTIONS
source: www.sierraclub.org/
population/reports/globalwarming.asp
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Carbon dioxide concentrations, globally averaged surface temperature, and sea level are projected to increase under all IPCC emissions scenarios during the 21st century…- for the six illustrative SRES emissions scenarios*, the projected concentration of CO2 in the year 2100* ranges from 540 to 970 ppm, compared to about 280 ppm in the pre-industrial era and about 368 ppm in the year 2000;
- projections using the SRES emissions scenarios in a range of climate models result in an increase in globally averaged surface temperature of 1.4 to 5.8°C over the period 1990 to 2100. This is about two to ten times larger than the central value of observed warming over the 20th century and the projected rate of warming is very likely to be without precedent during at least the last 10,000 years, based on paleoclimate data;
- globally averaged annual precipitation is projected to increase during the 21st century, though at regional scales both increases and decreases are projected of typically 5 to 20%;
- glaciers are projected to continue their widespread retreat during the 21st century;
- global mean sea level is projected to rise by 0.09 to 0.88 m between the years 1990 and 2100, for the full range of SRES scenarios, but with significant regional variations.
* SRES is the “Special Report on Emissions Scenarios” carried out by IPPC, the Intergovernmental Panel on Climate Change, in 2000.
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