Public “unclear on climate science”

If psychological tests on volunteers in the United States are to be believed, the general public does not understand the probabilities of climate change, the magazine New Scientist reported. Citing a study in the American journal Psychological Science, it said the public apparently thinks climate scientists are less certain about their conclusions than they actually are.


The results could explain why the minority views of "climate skeptics" get proportionally more attention from the general public than those of climate scientists. By nature, scientists are reluctant to express their findings as absolutely certain.


To make their results clearer to policy-makers and the public, the Intergovernmental Panel on Climate Change (IPCC) adopted seven verbal expressions of certainty in its 2007 report. It also used degrees of confidence to modify some statements.


David Budescu, of Fordham University’s psychology department in New York City, and colleagues asked 223 volunteers to read sentences from the IPCC reports that used the IPCC’s expressions. For example: "It is very likely that hot extremes, heat waves and heavy precipitation events will continue to become more frequent."


The researchers then asked the volunteers to estimate the probability conveyed by each sentence. The volunteers tended to underestimate the certainty of the sentences. Three-quarters of them thought that "very likely" meant less than 90% certain. To the experts, the term means a more than 90% likelihood of being correct.


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