Long run projections for climate change scenarios

The prediction of future temperature increases depends critically on the projections of future greenhouse gas emissions. Yet there is a vigorous debate about how these projections should be undertaken and how reasonable is the approach of the Special Report on Emissions Scenarios (SRES) published by the Intergovernmental Panel on Climate Change (IPCC)which forms the the basis of nearly all recent analyses of the impacts of climate change. In particular there has been significant criticism by Ian Castles and David Henderson regarding the plausibility of some scenarios.