Are climate model projections reliable enough for climate policy? Energy and Environment

The ongoing debate on the global warming and climate change highlights the possibility of increased incidences of extreme weather events world-wide, as the earth’s mean temperature is expected to rise steadily in the next 100 years according to most climate model projections. The recent IPCC (Intergovernmental Panel on Climate Change) document (IPCC, 2001) categorically states: The globally average surface temperature is projected to increase by 1.4C to 5.8C over the period 1990 to 2100. The projected warming is much larger than the observed changes during the twentieth century and is very likely to be without precedent during at least the last 10,000 years. The Climate Change document also summarizes various extreme weather events and their observed and projected changes based on model simulations. Among the extreme weather events summarized by IPCC are: Higher maximum temperature and more hot days over nearly all land areas; increase of heat index over land areas; more intense precipitation events and increased summer continental drying and associated risk of drought. Besides these weather events, the Climate change document also makes projections of major climatic events and states: El Niñ