Nov 3, 2011

Attribution of climate variations and trends to human influences and natural variability

Trenberth, Kevin E.
Wiley Interdisciplinary Reviews: Climate Change
  • States that past attribution studies of climate change have assumed a null hypothesis of no role of human activities
  • Argues the challenge, then, is to prove that there is an anthropogenic component
  • Argues that because global warming is “unequivocal” and ‘very likely’ caused by human activities, the reverse should now be the case
  • Argues the task, then, could be to prove there is no anthropogenic component to a particular observed change in climate, although a more useful task is to determine what it is . . . the benefit of doubt and uncertainties about observations and models are then switched
  • Argues the science community is much too conservative on this issue and too many authors make what are called ‘Type II errors’ whereby they erroneously accept the null hypothesis
  • Concludes that global warming is contributing to a changing incidence of extreme weather because the environment in which all storms form has changed from human activities