Here's why people doubt climate change

A new study has suggested that the representation of the dangers of global warming has led the people to doubt the phenomenon.

The University of NSW study that brings together climate science and cognitive psychology has revealed that many people don't believe in global warming because everyday life may have trained them to doubt it.

As the physical science underpinning human-induced climate change has grown more and more solid, more people have been growing sceptical of it.

''Simply presenting the facts and figures about global warming has failed to convince large portions of the general public, journalists and policy makers about the scale of the problem and the urgency of required action,'' the Sydney Morning Herald quoted the paper as saying.

''From a psychologist's perspective, this is not surprising," it added.

Two Sydney researchers, Ben Newell and Andy Pitman, identified different classes of perfectly normal psychological phenomena that can tend to turn people into so-called climate ''deniers''.

The first concerns ''sampling issues'' - the idea that people normally try to refer to real-life examples to draw conclusions and may be heavily influenced by recent media coverage.

''For example, if you read or hear opinions from climate change sceptics about 50 per cent of the time then this could lead to a bias in the perception of the balance of evidence in your mind - that is, that the science is only about 50% certain,'' said Newell.

People are also heavily influenced by ''framing issues'' - dealing with how information is presented to them. The figure 0.2 means the same as 20 out of 100, but the latter proportion makes the information seem much more concrete.

People construct mental models, which they use to judge new information, and these models are usually built only on a few fragments of information, the study said.

It used the analogy of most people's understanding of the link between cancer and smoking, which is not completely understood by most researchers yet widely accepted by the general public.

''By contrast, understanding how and why an increase in atmospheric carbon dioxide leads to warming and how and what we do as individuals and communities affects the composition of the atmosphere is much harder,'' said Newell.

The findings were published in the Bulletin of the American Meteorological Society.