Figure 6-3: Risks of climate
change damages would be reduced by stabilizing CO2 concentration. The
risks of adverse impacts from climate change are depicted for different magnitudes
of global mean temperature change, where global mean temperature change is used
as a proxy for the magnitude of climate change. Estimates of global mean temperature
change by the year 2100 relative to the year 1990 are shown on the righthand side
of the figure for scenarios that would lead to stabilization of the atmospheric
concentration of CO2 , as well as for the full set of SRES projections.
Many risks associated with warming above 3.5°C by the year 2100 would
be avoided by stabilizing CO2 concentration at or below 1,000 ppm.
Stabilization at a lower level would reduce risks further.White indicates neutral
or small negative or small positive impacts or risks; yellow indicates negative
impacts for some systems or low risks; and red means negative impacts or risks
that are more widespread and/or greater in magnitude. The assessment of impacts
or risks takes into account only the magnitude of change and not the rate of change.
Global mean annual temperature change is used as a proxy for the magnitude of
climate change, but impacts would be a function of, among other factors, the magnitude
and rate of global and regional changes in mean climate, climate variability and
extreme climate phenomena, social and economic conditions, and adaptation.
