Clearing up a climate of misunderstanding

We hear much talk of a scientific consensus on anthropogenic climate change, or at least we used to. Global warming has since fallen down the political agenda. At the same time there is a challenge to the thesis from mostly but not exclusively right-wing commentators who claim that there is no scientific consensus. They insist that many scientists disagree with the notion that global warming is down to human activity. The physical causes of climate change are scientifically testable, as is the distribution of opinion among climate scientists.

Is there a scientific consensus on climate change? That depends on how you define consensus, but in practical terms there is a consensus, with an overwhelming majority of scientists endorsing the view that climate change is largely man-made. A study to be published tomorrow of around 4,000 scientific papers within which a firm position is taken either way on the causes of global warming reveals that the figure is 97% arguing for anthropogenic climate change.

According to study leader John Cook, Climate Communication Fellow for the Global Change Institute at the University of Queensland,…

“Our findings prove that there is a strong scientific agreement about the cause of climate change, despite public perceptions to the contrary.

“There is a gaping chasm between the actual consensus and the public perception. It’s staggering given the evidence for consensus that less than half of the general public think scientists agree that humans are causing global warming.

“This is significant because when people understand that scientists agree on global warming, they’re more likely to support policies that take action on it.”

The study is based on on data retrieved from the Web of Science database for peer-reviewed research published between 1991 and 2011, using the topic searches “global warming” and “global climate change”. Of the 11,994 papers resulting from the search, 32.6% endorse the anthropogenic climate change argument, 66.4% express no opinion, 0.7% reject the thesis, and 0.3% state that the cause of global warming is uncertain.

One should not take the two-thirds that express no opinion in the same way as, say, the undecided in political opinion polls. Studies of the mechanics of atmospheric and oceanic physics, chemistry and other geoscience disciplines are often so focused on the technical details that there is either no room for wider contextual comment, or it would simply not be appropriate.