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.