• The impact of the Kyoto Protocol on global temperature is quite modest, especially for the first century. The reduction in global mean temperature in the Annex I case relative to the reference in 2100 is 0.13ºC; this compares with a difference of 0.17ºC from the Kyoto Protocol calculated by Wigley. The temperature reduction in the optimal run is essentially the same as the Kyoto runs by the 22nd century.