Simulated difference in mean annual temperature

Simulated difference in annual mean temperature (F) for the Midwest region, for each future time period (2021-2050, 2041-2070, and 2070-2099) with respect to the reference period of 1971-1999. These are multi-model means for the high (A2) and low (B1) emissions scenarios from the 14 (B1) or 15 (A2) CMIP3 global climate simulations. Color with hatching (category 3) indicates that more than 50% of the models show a statistically significant change in temperature, and more than 67% agree on the sign of the change (see text). Grid boxes whose centers are over the Great Lakes or outside the 8-state region are masked out. Temperature changes increase throughout the 21st century, more rapidly for the high emissions scenario.