There also are continued very sharp partisan and ideological differences on global warming. For example, while 47 percent of liberals and 42 percent of Democrats call it the world's leading environment problem, far fewer Republicans (26 percent), independents (29 percent) and conservatives (19 percent) agree.
Nonetheless, this perception has increased among all groups in the last year -- the number of Democrats who call global warming the top problem has gained 24 points, but it's up by 16 points among Republicans and by 11 points among independents. (It's up sharply among liberals and moderates, but much more slightly among conservatives.)
In another example, 54 percent of liberals and 51 percent of Democrats believe people are the main cause of global warming, while only about half as many conservatives or Republicans (29 percent and 24 percent, respectively) agree. And while 70 percent of Democrats call global warming a very serious problem for the future, just three in 10 Republicans agree.
There also are some differences by age, with adults younger than 40 more apt than their elders to think that global warming will be a very serious problem if left unchecked (65 percent vs. 52 percent), to think it actually can be addressed (70 percent vs. 58 percent) and to say the government should be doing more about it (75 percent vs. 66 percent).
Younger adults also are more likely, by a 16-point margin, to think that most scientists agree that global warming is occurring.
Even with the concern about global warming, there's relatively little willingness to use higher taxes to hold down energy consumption. Like last year, about eight in 10 Americans oppose increasing taxes on electricity so people use less of it, and two-thirds oppose raising gasoline taxes with the same aim. Sixty-two percent, however, continue to favor requiring lower greenhouse gas emissions from power plants.
Six in 10 feel they know at least a moderate amount about warming, but fewer seem fully informed. For example, while 56 percent think average temperatures around the world have been higher in the last three years than previously, that leaves a substantial number who don't think this is so. In fact the last three years have been among the six warmest in records since the late 1880s.
Fewer than last year, 41 percent rather than 50 percent, say temperatures in their own county have been higher; 17 percent (up from 9 percent) say it's been cooler. There seems a likely reason: This poll happens to have been conducted during an unusual springtime cold snap in much of the country.
Politically, trust to deal with the issue tilts heavily to the Democrats. Americans by 59-19 percent say they trust the Democrats in Congress over President Bush to handle global warming, and by 53-21 percent prefer the Democrats on the environment overall.
To the administration's possible further dismay, the public also trusts the Democrats over Bush to handle issues involving the national parks, by 57-24 percent.
That's despite steps such as Bush's "Centennial Initiative" to match $1 billion in federal funding for the parks system with $1 billion in private donations by 2016, and his designation of an island chain northwest of Hawaii as a national monument, creating the largest protected marine reserve in the world.