Betsy Taylor, a Democratic strategist and consultant who represents a coalition of wealthy environmentally minded donors, said plenty of environmentalists support Obama. But some have been waiting for the president to renew his call for more action on climate change before they donate more. They saw Romney’s remarks as "a great opportunity for the president to step up and distinguish himself," Taylor said.

The political arms of the Sierra Club, the Natural Resources Defense Council and the League of Conservation Voters see it as a winning issue, particularly in races for the Senate and the House of Representatives. They’ve targeted candidates who deny climate change; the League of Conservation Voters, for example, has a “Flat Earth Five" it’s targeting. They all say it was insulting for Romney to say that families don’t care about climate change.

"I would hazard to guess that those people who got flooded out by Hurricane Isaac are super worried about climate change," said Heather Taylor-Miesle, director of the NRDC Action Fund. "The seas rose in New Orleans. To imply that those families don’t care about sea rise is both insensitive and completely oblivious. This is an issue that has real consequences for American families."

Romney has said previously that he believes climate change is occurring and that human activity is a contributing factor. During the Republican primary season, though, he said he didn’t believe it was the right course to spend “trillions and trillions” to reduce carbon emissions. More recently, he said in a questionnaire submitted to Science Debate, a non-profit organization focusing on science issues in the presidential campaign, that he believes human activity contributes to global warming and that policymakers should consider the risk of negative consequences.

Frank Maisano, a lobbyist whose firm represents energy interests and who has been involved in climate change discussions for 15 years, cautioned not to read too much into Romney’s dig about the rise of the oceans. It was designed to show Obama is "a little bit out of touch," he said.

"Right now, you need someone who cares about you rather than these larger, soaring rhetorical issues," Maisano said.

Jim DiPeso of ConservAmerica had the same reaction.

"(Romney) acknowledged that science has shown there is a human role in global warming,” said DiPeso, who represents a national grassroots organization of conservation-minded Republicans who would like to see a fiscally conservative approach to capping carbon emissions.

DiPeso said he hopes Romney’s acknowledgement will give Republicans lower down on the ticket the freedom to talk about climate change, an issue that once had Republican support. Policymakers may differ on how to address emissions, but carbon dioxide molecules are apolitical, he said.

“Because we’ve gotten to the point where a good Republican can’t acknowledge the real science that backs up climate change without being cast as some sort of infidel, or somebody who’s not a real conservative,” he said.

There are ways to make climate change part of the overall discussion on energy without actually saying "climate change," said Sen. Mark Begich, D-Alaska, who hails not only from an energy-producing state, but one that has to grapple with the eroded coastlines, fiercer storms and melting icepack caused by the changing climate.

Rather than talking about climate change in a vacuum, Begich said, Democrats need to talk about it in the context of national security, energy security and a thriving green economy.

"I think we have a habit as Democrats, we want to get touchy feely and policy wonk stuff to death," he said, while speaking at an energy panel at the convention. "Instead, just plain and simple, this is about economic security, it’s about national security. We cater so deep to our base, we forget the average person is looking at, well, how does it affect them? What does it do for national security? What does it do for the economy?"

Plenty is at stake, said Marc Weiss, a documentary filmmaker and Obama supporter whose film on the history of the environmental movement will be released in the coming month. He continues to support the Obama-Biden campaign. But Weiss wants more voices to speak out on climate.

"It’s not just about the moral imperative," he said. "I think it could be a winning political strategy. There’s a dramatic choice here, and for me it’s a no-brainer."