Figure
SPM-3: The different socio-economic assumptions underlying
the SRES scenarios result in different levels of future emissions of greenhouse
gases and aerosols.These emissions in turn change the concentration of
these gases and aerosols in the atmosphere, leading to changed radiative forcing
of the climate system. Radiative forcing due to the SRES scenarios results in
projected increases in temperature and sea level, which in turn will cause impacts.
The SRES scenarios do not include additional climate initiatives and no probabilities
of occurrence are assigned. Because the SRES scenarios had only been available
for a very short time prior to production of the TAR, the impacts assessments
here use climate model results that tend to be based on equilibrium climate change
scenarios (e.g., 2xCO2 ), a relatively small number of experiments
using a 1% per year CO2 increase transient scenario, or the scenarios
used in the SAR (i.e., the IS92 series). Impacts in turn can affect socio-economic
development paths through, for example, adaptation and mitigation. The highlighted
boxes along the top of the figure illustrate how the various aspects relate to
the integrated assessment framework for considering climate change (see Figure
SPM-1).
