claim: Temperatures in the Southwest increased by nearly two degrees Fahrenheit (one degree Celsius) from 1901 to 2010, and some climate models forecast a total rise of six degrees or more by the end of this century.
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.