Washington (CNN) - A new national poll indicates that some Americans are cooling to global warming.
According to an ABC News/Washington Post survey released Tuesday - less than two weeks before the start of a global conference on climate change in Copenhagen, Denmark - 72 percent of those polled believe that climate change is happening, down 8 points over the past year.
The poll indicates that the rise in skepticism is mostly due to a shift among Republicans and independents. According to the survey, 54 percent of Republicans questioned believe global warming is happening, down 22 points over the past three-and-a-half years, with a drop of 15 points among independents. The belief in climate change dipped 6 points among Democrats during the same period of time.
The survey's release comes as a Democratic-sponsored "cap-and-trade" proposal to cut pollution slowly makes it way through Congress. The bill calls for the federal government to limit the amount of greenhouse gases that companies can produce in their factories or power plants, and to penalize companies that exceed greenhouse gas limits with fines or by making those businesses pay money to other companies that produce less pollution.
The legislation narrowly passed the House this summer, but won't be considered by the full Senate until next spring. According to the poll, Americans support such a bill by a 53 percent to 42 percent margin. Six in 10 people questioned in a CNN/Opinion Research Corporation survey conducted last month supported a "cap and trade" bill.
The ABC News/Washington Post poll was conducted November 12-15, with 1,001 adults questioned by telephone. The survey's sampling error is plus or minus 3 percentage points.
–CNN Deputy Political Director Paul Steinhauser contributed to this report