Changes
in Vegetation Distribution 2070-2099, relative to 1961-1990
Temperature-driven
Fire-mediated
HadCM3 higher
HadCM3 lower
PCM higher
PCM lower
Source: A
Luers/Union of Concerned Scientists
Changes driven primarily by
temperature, such as reductions in the extent of alpine/subalpine forest and
the displacement of evergreen conifer forest by mixed evergreen forest, are
consistent across models and more pronounced under A1fi by the end of the
century. Changes driven by precipitation and changes in fire frequency are
model-dependent and do not exhibit consistent inter-scenario differences.
Most changes are apparent by mid-century, with the exception of changes in
desert cover. The shift from evergreen conifer to mixed evergreen forest and
expansion of grassland are consistent with previous impact analyses12,
while the extreme reduction in alpine/subalpine forest and expansion of
desert had not been seen previously.
