Uncertainty and assessment of the issues posed by urgent climate change. An editorial comment

Climate change raises a number of difficult issues concerning the management of scientific uncertainty. Urgent decisions seem to call for quantified probability statements as the basis of rational policy-making. Yet the answers to many important questions such as the likely rate of sea level rise are not easily quantified, and the utilization of any estimates based on 'collective subjective probability' necessarily depends on value-laden judgments about burden-of-proof and the distribution of risk. We suggest that there is a need for a new form of risk assessment that is based in, but not limited to, the scientific community, in which rapid but credible processes address the critical questions that we are now facing.