Figure SPM-2: Reasons for
concern about projected climate change impacts. The risks of adverse impacts from
climate change increase with the magnitude of climate change. The left part of
the figure displays the observed temperature increase relative to 1990 and the
range of projected temperature increase after 1990 as estimated by Working Group
I of the IPCC for scenarios from the Special Report on Emissions Scenarios. The
right panel displays conceptualizations of five reasons for concern regarding
climate change risks evolving through 2100. White indicates neutral or small negative
or 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 in the figure as a proxy for the magnitude of climate change, but
projected impacts will 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.
