Over the last few years, consensus seemed to have coalesced around the presence of global warming: it was real, and politicians from both sides of the aisle--including the GOP's 2008 presidential nominee, John McCain--said so.
Now that consensus is slipping, according to new data from the Pew Research Center's last national survey.
While belief in climate change has been in the 70-percent range since 2006, now, only 57 percent of Americans think there is "solid evidence the earth is warming"--a drop of 14 percentage points since April 2008.
The decline in certainty spans party lines, though it's most pronounced among independents--22 percent fewer of whom see evidence of global warming:
At the same time, Americans think climate change is a less serious problem--which makes sense if fewer think it's a problem at all--as 35 percent say it's "very serious," compared to 44 percent in April 2008.
As a result, it would seem like a bad time for Democrats to be selling a comprehensive climate legislation (aka cap-and-trade) that has stalled in the Senate since the House barely passed it in June.
But Pew finds that Americans support cap-and-trade 50 percent to 39 percent, even as the question reminded them that the policy "could lead to higher energy prices."
The politics of cap-and-trade may or may not have something to do with the shift in attitude on climate change. With the cap-and-trade debate, climate change has been newly politicized: it was not a major issue in the 2006 elections, and in 2008, Barack Obama and John McCain both saw it as a problem and proposed similar strategies for dealing with it.
In 2009, cap-and-trade has been met with harsh resistance--from Republicans, business groups, and conservative activists like those at FreedomWorks, which made cap-and-trade a big part of its summer agenda. With Democrats preoccupied by health care, there appears to be a more organized messaging effort against cap-and-trade than for it.
But most of that opposition has centered around the cost of cap-and-trade, rather than the science behind climate change--though it's possible that anti-cap-and-trade messaging has led Americans to view the cost of the policy as a cost of belief in climate change.
According to Pew, the cap-and-trade debate has barely registered with the American public. So while it appears to be the main variable in public perceptions of climate since 2006, it might have little to do with Americans' changing views: a majority of Americans--55 percent--say they have heard nothing at all about cap-and trade plans being developed in Congress, vs. 14 percent who say they've heard a lot and 3 percent who say they've heard a little.
It's quite possible that anti-cap-and-trade messaging has seeped into America's unconscious mind, affecting opinion on global warming even as the public says it's heard very little about the legislation being proposed. But it's dubious that, on a conscious level at least, politics has much to do with the change.