Applying risk analytic techniques to the integrated assessment of climate policy benefits.

Abstract

The two main flavours of integrated climate change assessment (formal cost benefit analysis and the precautionary approach to assessing dangerous anthropogenic interference with the climate system) also reflect the major controversies in applying climate policy. In this assessment, we present an approach to using risk weighting that endeavours to bridge the gap between these two approaches. The likelihood of damage in 2100 to four representative economic damage curves and four biophysical damage curves according to global mean warming in 2100 is assessed for a range of emissions futures. We show that no matter which future is followed, the application of climate policy through mitigation will reduce the most damaging outcomes first. By accounting for the range of plausible risks, the benefit of mitigation can be substantial for even small reductions in emissions. Disparate impacts calibrated across multiple metrics can be displayed in a common format, allowing monetary and non-monetary impacts and benefits to be assessed within a single framework. The applicability of the framework over a wide range of climate scenarios, and its ability to function with a range of different input information (e.g. climate sensitivity) also shows that it can be used to incorporate new or updated information without losing its basic integrity.