A Michigan congressman wants to put a 50-cent tax on every gallon of gasoline to try to cut back on Americans' consumption.

Polls show that a majority of Americans support policies that would reduce greenhouse gases. But when it comes to paying for it, it's a different story.

Rep. John Dingell, D-Mich., wants to help cut consumption with a gas tax but some don't agree with the idea, according to a new poll by the National Center for Public Policy Research.

The poll, scheduled to be released on Thursday, shows 48 percent don't support paying even a penny more, 28 percent would pay up to 50 cents more, 10 percent would pay more than 50 cents and 8 percent would pay more than a dollar.

"I don't want to pay more, I don't think anyone wants to," said Karen Deacon, a motorist.

"I think that wouldn't make any sense," said Frankie Hoe, a motorist. "Ugh ... who's making the money from all this and where is that money going? Is it going to go green? I don't see any green things anywhere."

The automobile is the nation's biggest polluter; Americans use more gas than the next 20 countries combined.

Some environmentalists and economists say pain at the pump may be bad for Americans, but good medicine for a sick planet.

But others say it wouldn't change much. Even if Americans abandoned their cars, global emissions would fall by less than one percent.

"A tax on gas is a way to reduce dependence on import oil, reduce traffic congrestion and reduce carbon emissions," said Lester Brown, president of the Earth Policy Institute.

The Earth Policy Institute proposes raising the gas tax 30 cents per gallon each year over a decade and offset with a reduction of income taxes, Brown said.

David Ridenour, vice president of the National Center for Public Policy Research, said the proposal wouldn't help long term.

"I think when you are talking about raising gas prices, there may be short-term reduction, put off vacations, but bottom line is over long term, that isn't going to have much of an effect," Ridenour said.

While Dingell's idea will likely lie dormant until after the 2008 election, the idea of carbon taxes is not. Hillary Clinton, Barack Obama and John McCain all support some type of system that either directly or indirectly will raise prices to penalize polluters.

FOX News' William La Jeunesse contributed to this report.