Attribution of Weather and Climate-Related Events

Unusual or extreme weather and climate-related events are of great public concern and interest, yet there are often conflicting messages from scientists about whether such events can be linked to climate change. There is clear evidence that climate has changed as a result of human-induced greenhouse gas emissions, and that across the globe some aspects of extremes have changed as a result. But this does not imply that human influence has significantly altered the probability of occurrence or risk of every recently observed weather or climate-related event, or that such events are likely to become significantly more or less frequent in the future. Conversely, it is sometimes stated that it is impossible to attribute any individual weather or climate-related event to a particular cause. Such a statement can be interpreted to mean that human-induced climate change could never be shown to be at least partly responsible for any specific weather event, either the probability of its occurrence or its magnitude. There is clear evidence from recent case studies that individual event attribution is a feasible, if challenging, undertaking.