ABSTRACT
In any estimates of future climate change there are a number of sources of uncertainty. Some of these arise from the science itself, and some from uncertainty about future human behaviour – especially future emissions of greenhouse gases. In the case of future climate impacts, there are a number of different assumptions, and a number of models of different parts of the climate system. There are the uncertainties in models that calculate the impacts of climate change, for example on crop production, river flow, flooding, coastal storm surges, and damages. People respond in different ways to uncertainty. The United Nations Framework Convention on Climate Change states that the central objective must be to avoid concentrations of greenhouse gases that may lead to 'dangerous interference with the climate system'. Contrarians sometimes characterise 'environmentalism' as a new religion or ideology, or as some new form of totalitarianism. Some genuine sceptics take the 'devil's advocate' position to stimulate debate and test propositions.
