Climate Change Scenarios and Sea Level Rise Estimates for the California 2009 Climate Change Scenarios Assessment

For the 2008 California Climate Change Assessment, to further investigate possible future
climate changes in California, a set of 12 climate change model simulations was selected and
evaluated. From the Intergovernmental Panel on Climate Change Fourth Assessment activities
projections, simulations of twenty-first century climates under a B1 (low emissions) and an A2
(a medium-high emissions) emissions scenarios were evaluated. Six climate models were
chosen. These emission scenarios and climate simulations are not “predictions,” but rather are
possible scenarios of plausible climate sequences that might affect California in the next
century. Temperatures over California warm significantly during the twenty-first century in
each simulation. Also the rise in global sea level, and by extension the rise of sea level along the
California coast, increases. Along with this, there are marked increases in the frequency,
magnitude, and duration of heat waves and sea level rise extremes. There is quite a strong
inclination for higher warming in summer than winter and greater warming inland than along
the coast. In several of the simulations there is a tendency for drier conditions to develop during
mid-and late-twenty-first century in Central and Southern California, and along with this, a
decline in winter wave energy along the California coast.