OSLO More than two-thirds of the world's people are worried by global warming with Americans among the least anxious even though their nation is the top source of greenhouse gases, an opinion poll showed on Tuesday.
The survey, of more than 14,000 people in 21 nations for BBC World television, showed most respondents around the world reckoned the United States was more to blame that other nations for rising temperatures.
"More than two-thirds (68 percent) of the world is concerned about climate change with the South Africans (82 percent) and Brazilians (87 percent) most concerned," a statement of main findings said.
At the low end of anxiety were Americans on 57 percent and Indians with 59 percent.
Almost all scientists say temperatures are rising because of a build-up of greenhouse gases in the atmosphere from burning fossil fuels, threatening ever more floods, droughts, heatwaves and rising seas.
And the poll, by the Synovate research group, said two-thirds of all respondents reckoned the United States was more to blame than any other country for the problem.
"Almost four in five Americans, however, think that no one country is to blame," it said. The United States is the top world emitter of greenhouse gases with almost a quarter of the total, ahead of China, Russia and India.
In per capita terms, Americans are responsible for about 20 metric tons of greenhouse gases each per year, against a world average of below 4 metric tons.
Still, the survey found 22 percent of U.S. citizens had bought or planned to buy a smaller car -- ahead of a world average of 20 percent.
U.S. President George W. Bush pulled out of the Kyoto Protocol, the main U.N. plan for curbing emissions of greenhouse gases, in 2001. He said Kyoto would cost U.S. jobs and wrongly excluded developing nations from goals for 2012. He has instead focused on big investments in technology, such as hydrogen or biofuels.