The burden of proof for climate change

Terra Daily via SPX: The debate may largely be drawn along political lines, but the human role in climate change remains one of the most controversial questions in 21st century science. Writing in WIREs Climate Change Dr Kevin Trenberth, from the National Center for Atmospheric Research, argues that the evidence for anthropogenic climate change is now so clear that the burden of proof should lie with research which seeks to disprove the human role.

In response to Trenberth's argument a second review, by Dr Judith Curry, focuses on the concept of a 'null hypothesis' the default position which is taken when research is carried out. Currently the null hypothesis for climate change attribution research is that humans have no influence.

"Humans are changing our climate. There is no doubt whatsoever," said Trenberth. "Questions remain as to the extent of our collective contribution, but it is clear that the effects are not small and have emerged from the noise of natural variability. So why does the science community continue to do attribution studies and assume that humans have no influence as a null hypothesis?"

To show precedent for his position Trenberth cites the 2007 report by the Intergovernmental Panel on Climate Change which states that global warming is "unequivocal", and is "very likely" due to human activities...

A stop sign reading "stop global warming", located at the intersection of 19th and Q Streets, N.W., in the Dupont Circle neighborhood of Washington, D.C., during the Second North American blizzard of 2010. This is the sort of image that denialists find ironic, even though an intensified water cycle implies more intense snowstorms. Shot by AgnosticPreachersKid, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license