claim: Small increases in average temperature translate to big increases in the number of extremely hot days, and those hot days have a big impact.
evidence: For example, based on projections made by the Intergovernmental Panel on Climate Change and results from the United Kingdom Hadley Centre's climate model (HadCM2), a model that accounts for both greenhouse gases and aerosols, by 2100 temperatures in Idaho could increase by 5 °F (2.8 °C) (with a range of 2-9 °F) in winter and summer and 4 °F (2.2 °C) (with a range of 2-7 °F) in spring and fall.