Aug. 9--Monday's National Clean Energy Summit 2.0 will bring a parade of celebrated public policy experts to Las Vegas to discuss greening the country's economy.

But as leaders including former President Bill Clinton, former Vice President Al Gore and California Gov. Arnold Schwarzenegger encourage investments in alternative energy, their policy prescriptions could face serious headwinds from changing public opinions.

Recent surveys show Americans cooling to global warming, and they're even less keen on environmental policies they believe might raise power bills or imperil jobs. Those sentiments could mean a tougher road ahead for elected officials looking to fund investments in renewable power or install a carbon cap-and-trade system.

"Right now, Americans are more concerned about the economy than the environment," said Frank Newport, editor-in-chief of the Gallup Poll. "The politician who says, 'I'm going to cripple jobs and shut down factories' would be in trouble in this economy."

WHAT THE NUMBERS SAY

Here's what Gallup found: The number of Americans who say the media have exaggerated global warming jumped to a record 41 percent in 2009, up from 35 percent a year ago. The most marked increase came among political independents, whose ranks of doubters swelled from 33 percent to 44 percent. Republican doubters grew from 59 percent to 66 percent, while Democratic skeptics stayed at around 20 percent.

What's more, fewer Americans believe the effects of global warming have started to occur: 53 percent see signs of a hotter planet, down from 61 percent in 2008. Global warming placed last among eight environmental concerns Gallup asked respondents to rank, with water pollution landing the top spot.

Another recent Gallup study found that, for the first time in 25 years of polling, more Americans care about economic growth than the environment. Just 42 percent of people surveyed said the environment takes precedence over growth, while 51 percent asserted expansion carries more weight. That reverses results from 2008, when 49 percent of respondents said the environment was paramount and 42 percent said economic growth came first. In 1985, the poll's first year, 61 percent placed a bigger priority on the environment, while 28 percent ranked economic growth highest.

All those results indicate trends that pose big challenges for the environmental movement, Gallup's researchers concluded. More pointedly, the findings signal potential trouble for policies designed to curb global warming.

"It's a conundrum. You can't just say to those interested in global warming that they need to do a better job of PR because they have been trying so hard," Newport said. "Al Gore won a Nobel Peace Prize for his efforts. He made a widely seen movie, and his book sold many copies. Yet, with all that, it hasn't worked. You would have to say that, somehow, they're not getting the message across."

Ask Daniel Weiss, a senior fellow and director of climate strategy at the left-leaning Center for American Progress, why increasing numbers of Americans dispute global warming and place the economy ahead of the environment, and he'll say those findings are wrong.

"I don't accept their premise. I think the Gallup Poll is mistaken," said Weiss, whose organization will send its chief executive officer, former White House Chief of Staff John Podesta, to Monday's clean energy confab. "I would want to look at their questions to see how they got to this place."

Weiss pointed to surveys that contradict Gallup's results. A Pew Environmental Group poll found that 77 percent of voters want lawmakers to reduce carbon dioxide emissions, and 55 percent said efforts to curb global warming will create jobs. Another poll from the National Wildlife Federation found that 55 percent of those polled strongly support a global warming plan that reduces pollution.