Barack Obama's sense of urgency in getting Congress and the international community to act on climate change does not appear to have rubbed off on the average American, a new study published today reveals.

Even as the president pressed the G8 and the world's major polluters to resist cynicism and the pressure of the economic recession to act against global warming, a majority of Americans remain unconvinced that humans are responsible for climate change, or that there is an urgent need to act.

About 49% of Americans believe the Earth is getting warmer because of the burning of fossil fuels and other human activity, the survey by the Pew Research Centre and the American Association for the Advancement of Science said. Some 36% attributed global warming to natural changes in the atmosphere and another 10% said there was no clear evidence that the earth was indeed undergoing climate change.

Scientists in contrast are overwhelmingly persuaded that global warming is caused by humans - some 84% blame human activity. A strong majority - some 70% - also believe it is a very serious problem. Despite that degree of consensus, some 35% of Americans continues to believe - wrongly it turns out - that climate change remains a matter of scientific controversy. Only about 47% of the public views climate change as a very serious problem, a finding that has remained stable over the years, the survey said. In other public opinion polls over the years, climate change has ranked near the bottom of the list of pressing problems.

The Pew poll, like others in the past, also found attitudes towards climate change breaking down according to political allegiance. Some 67% of Republicans either deny the existence of climate change or attribute the phenomenon to natural causes. In contrast, 64% of Democrats believe that the earth is getting warmer because of human activity.