House Democrats outlined a plan Tuesday to cut greenhouse gases by 20 percent over the next decade and 83 percent by mid-century, proposing a speedier ramp-up of emission limits than urged by the White House.

WASHINGTON — House Democrats outlined a plan Tuesday to cut greenhouse gases by 20 percent over the next decade and 83 percent by mid-century, proposing a speedier ramp-up of emission limits than urged by the White House.

But the draft proposal to be taken up by the House Energy and Commerce Committee leaves to further negotiations one of the most contentious issues: It does not say how pollution allowances would be distributed or whether they will be sold by auction or given away to polluting industries.

President Barack Obama has called for auctioning off all emission credits and using the billions of dollars to help people pay for higher energy costs and development of new, more climate friendly energy sources.

Still, the so-called "discussion draft" outlines an aggressive ramp-up of limits on greenhouse gases, especially carbon dioxide from the burning of fossil fuels.

It seeks to blunt some of the costs of the program to consumers by calling for tougher energy efficiency standards from appliances to cars and by requiring utilities to move toward greater use of solar, wind and other renewable energy sources to generate electricity.

House Speaker Nancy Pelosi, D-Calif., called the draft "a strong starting point" and reiterated that she plans to take up climate legislation in the full House later this year.

Unlike a Senate climate bill that failed last year, the House proposal combines broad energy programs aimed at reducing use of fossil fuels with a mandatory "cap-and-trade" system that would limit carbon dioxide and other greenhouse gas releases into the atmosphere.

The draft crafted by Rep. Ed Markey, D-Mass., chairman of the subcommittee dealing with climate legislation, calls for cutting greenhouse gas emissions by 20 percent by 2020, compared with 2005 levels, reflecting a view by many scientists that early action is needed to achieve the greenhouse gas reductions that will avoid serious future climate warming.

Obama, whose long-term goals on emission cuts are similar to what is being proposed by the House Democrats, has called for a more gradual ramp-up of 14 percent by 2020.

Markey and Rep. Henry Waxman, D-Calif., the committee's chairman, sought to deflect Republican criticism that the climate legislation would raise energy prices and cause economic harm.

"Our goal is to strengthen our economy by making America the world leader in new clean energy and energy efficiency technology," said Waxman in a statement.

"We will create jobs by the millions, save money by the billions and unleash energy investments by the trillions," added Markey.

But getting the bill through the committee may be a challenge.

Republicans have criticized the cap-and-trade approach. Rep. Joe Barton of Texas, the committee's ranking GOP member, says it amounts to a huge tax on consumers because it will spawn dramatically higher energy costs.

While Democrats hold a 34-23 advantage over Republicans on the committee, a half dozen Democratic moderates also have expressed concerns over climate legislation that would increase energy costs, especially Obama's proposal to auction off all energy allowances.

Industry groups that in general embrace the need for limits on greenhouse gases, have argued that allowances should be given free to operators of coal-burning power plants and energy-intensive manufacturing to blunt the cost of cutting emissions.

Waxman and Markey hope to work out agreement on that issue as the draft proposal moves toward a vote in committee. They anticipate a committee vote on the climate legislation by mid-May.