LONDON The country that produces the most greenhouse gases in the world also has the most people who are not yet convinced global warming is linked to human activities, according to a new report.

That country is the United States of America.

An ACNielsen survey of more than 25,000 Internet users found that U.S. poll participants were not as concerned about global warming as the survey participants from 46 countries.

Just 42 percent of the Americans surveyed rated global warming as “very serious.”

The survey also discovered that 13 percent of Americans have never heard nor read of global warming.

The United States produces a quarter of the world’s greenhouse gases, which scientists say causes the world to become hotter as they trap heat inside the earth’s atmosphere. These gases are made when fossil fuels are burned.

The survey found that the Latin American respondents were the most worried about global warming. Ninty-six percent of these Latin Americans had heard of global warming; 75 percent of them rated it “very serious.”

Respondents from China and Brazil were the most convinced of global warming’s link to human activities.

Overall, 57 percent of the respondents considered global warming a “very serious problem.” Another 34 percent rated it a “serious problem.”

A United Nations report released late last week said that there is a 90 percent chance humans have been the cause of global rise in temperatures over the last 50 years.

Most industrialized nations have backed capping emissions of greenhouse gases through the ratification of the U.N.’s Kyoto Protocol.

The United States government, however, under President George W. Bush has refused pass this 2001 protocol which calls on factories to curb emissions.

A day after the ACNielsen poll was reported, U.S. scientists told a congressional committee that their findings on global warming were edited to favor the White House’s worldview.

Rick Piltz testified that he resigned his post as a U.S. government scientist in 2005 over pressure to doctor his work by Phil Cooney, the former chief of staff at the White House Council on Environmental Quality.

Cooney, an ex-lobbyist for the American Petroleum Institute, required documents on climate change to have his personal stamp of approval before publishing, said Piltz.

“His edits of program reports, which had been drafted and approved by career science program managers, had the cumulative effect of adding an enhanced sense of scientific uncertainty about global warming and minimizing its likely consequences,” he said to the House Oversight and Government Reform Committee.

Cooney resigned in 2005 to work for oil giant ExxonM