Scientific research on climate change points one way. Photo: Reuters
Having doubts over climate change and the role of humans? You're unlikely to find many scientists who share your uncertainty.
That is the finding of a University of Queensland-led study that surveyed the abstracts of almost 12,000 scientific papers from 1991-2011 and claims to be the largest peer-reviewed study of its kind.
Of those who a stated a position on the evidence for global warming, 97.1 per cent endorsed the view that humans are to blame. Just 1.9 per cent rejected the view.
The report's lead author, John Cook, a fellow at the University of Queensland's Global Change Institute and founder of the website skepticalscience.com, said the scientific consensus was overwhelming, growing and had been around since the early 1990s.
He said that while the number of papers rejecting the consensus was "vanishingly small", his research suggested the public was under the impression the debate was split 50-50.
"When people think scientists agree, they are more likely to support a carbon tax or general climate action," he said.
"But if they think scientists are still arguing about it, they don't want to do anything about it." Carbon dioxide levels in the atmosphere are about 400 parts per million and rising – the highest in more than 3 million years.
The fifth assessment report of the Intergovernmental Panel on Climate Change is due to update its findings on research into global warming and the potential impact on societies and the environment from this September.
Mr Cook said scientists now found less need to state their position on climate change in abstracts summarising their papers, "just as geographers find no reason to remind readers that the earth is round".
The survey is published in the journal Environmental Research Letters. It is based on the work of 24 scientists and others recruited through skepticalscience.com. Ratings were cross-checked and authors were contacted to rate their own papers.
Mr Cook said the level of endorsement – 97.2 per cent of the one-fifth who replied – was in line with the overall findings.
The strength of the scientific consensus could be likened to the theory of plate tectonics, or continental drift, that took 50 years to gain acceptance. In that case, he said the media found little reason to stoke controversy because there was "no political or ideological issue with plate tectonics", he said.
"If people disagree with what we've found we want to know," said Mark Richardson of the University of Reading in England, one of the authors of the study that looked at English-language studies by authors in more than 90 nations.
Another co-author, Dana Nuccitelli of Skeptical Science, said he was encouraging scientists to stress the consensus "at every opportunity, particularly in media interviews".
Opinion polls in some countries show widespread belief that scientists disagree about whether climate change is caused by human activities or is part of natural swings such as in the sun's output.
A survey by the US Pew Research Center published in October last year found 45 per cent of Americans said "Yes" when asked: "Do scientists agree Earth is getting warmer because of human activity?" About 43 per cent said "No".
Governments have agreed to work out, by the end of 2015, a deal to slow climate change that a UN panel of experts says will cause more floods, droughts and rising sea levels.