Climate Consensus ‘Skewing’ Science
CONSENSUS decision-making on climate change has oversimplified the problem and how to solve it, and unduly politicised the process, a leading US climate scientist has said.
Writing in The Weekend Australian today, Judith Curry, professor and chairwoman of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology, said the consensus-building process itself could be a source of bias.
“A strongly held prior belief can skew the total evidence that is available subsequently in a direction that is favourable to itself,” Professor Curry said.
“The consensus-building process has been found to generally act in the direction of understating the uncertainty associated with a given outcome.”
Professor Curry has led debate in the science community about the process of reviewing climate change, including giving testimony before the US house subcommittee on environment this year, remarking on the many large uncertainties in forecasting future climate.
Australian climate scientist David Karoly, professor of atmospheric science at the University of Melbourne and a review editor of the Intergovernmental Panel on Climate Change’s fifth assessment report, said he did not believe uncertainty was underplayed in the IPCC assessments. “There is a thorough and comprehensive consideration of uncertainty in the IPCC reports and in their summaries, including estimates of uncertainties through multiple different approaches,” Professor Karoly said.
“It has been reported that uncertainty is referred to 42 times in 31 pages in the leaked draft of the summary of the IPCC report to be released at the end of next week.
“The comprehensive treatment of uncertainty in the IPCC assessment process is much better than in any single or group of peer-reviewed research papers.”
Professor Curry said virtually all climate scientists agreed on the basic physics of what impact increased levels of carbon dioxide in the atmosphere would have on temperature.
“If all other things remain equal, more carbon dioxide in the atmosphere will have a warming effect on the planet,” Professor Curry said.
“Further, virtually all agree that the planet has warmed over the past century, and that humans have had some impact on the climate.
“But understanding the causes of recent climate change and predicting future change is far from a straightforward endeavour.”
Professor Curry has been involved in lively international debate in the lead-up to the release next week of the IPCC’s fifth update report. Debate has centred on the inability of many climate models to predict accurately actual global temperature changes.
She said climate scientists did “not need to be consensual to be authoritative”.
“Authority rests in the credibility of the arguments, which must include explicit reflection on uncertainties, ambiguities and areas of ignorance and more openness for dissent,” she said.
“The role of scientists should not be to develop political will to act by hiding or simplifying the uncertainties, either explicitly or implicitly, behind a negotiated consensus.”