A majority of Americans – about 75 percent – support regulating greenhouse gases from power plants, cars and manufacturing that would reduce global warming, according to a new Washington Post-ABC News poll.

But only a bare majority – 52 percent – support a cap-and-trade approach to reducing greenhouse gas emissions and 42 percent oppose such a program, which is the type of approach taken in the Waxman-Markey climate legislation expected to be voted on in the US House of Representations, possibly Friday.

Support for controls on emissions wavered even more as those polled were asked whether they’d pay higher electricity prices to help bring about reduced greenhouse gases.

Only 44 percent said they would back a cap-and-trade system if it meant monthly electricity bills would be $25 higher. Support was stronger, at 56 percent, if the proposed monthly electricity increase was just $10 a month, according to the randomized poll of 1,001 adults.

The Congressional Budget Office has estimated that regulating greenhouse gases would cost the typical household about $175 a year in 2020, when the shift to clean energy and emissions controls would be in high gear.

But opponents of the pending climate legislation, especially conservative Republicans, argue that costs will be much higher.

The poll found that people living in households making less than $50,000 a year were the most concerned about the costs of the climate regulation.

Young people were the most supportive of federal regulation to control climate-related emissions (about 60 percent said they supported cap-and-trade) and senior citizens the least supportive (about 40 percent said they favored cap-and-trade).

Cap-and-trade is a market-based approach to controlling GHG emissions. It sets caps on the amount of pollution companies are allowed and lets them bid for extra credits if they go over their emissions allowance or sell credits if they keep under pollution limits. Limits for everyone are lowered over time to reduce carbon emissions.