Figure 3-2: Scaled outputs
of mean December-February (left) and June-August (right) temperature and precipitation
change by the 2050s relative to 1961-1990 over land grid boxes representing
Central North America (top), Southern Africa (middle), and Southern Asia (bottom)
from eight simulations with five AOGCMs (experiments b, c, e, h, and a four-member
ensemble from t; see Table 3-5). Simulations assume forcing by greenhouse gases
but not aerosols, and are standardized according to the climate sensitivity of
each AOGCM. Lines connect four points for each simulation, all in the same order
from the origin: B1-low, B2-mid, A1-mid, A2-high. Each point represents the standardized
regional changes in climate from the AOGCM, linearly scaled according to the global
warming estimated with a simple climate model for one of four preliminary SRES
marker emissions scenarios (B1, B2, A1, and A2) and a value of the climate sensitivity
(low = 1.5°C; mid = 2.5°C, and high = 4.5°C). Also plotted are ±1
and ±2 standard deviation ellipses from the 1400-year HadCM2 and 1000-year
GFDL unforced simulations, which are used to indicate natural multi-decadal variability
and are orientated according to the correlation between modeled 30-year mean temperature
and precipitation. Results from two other AOGCMs did not extend to the 2050s (Carter
et al., 2000).
