June 26 (Bloomberg) -- President Barack Obama prodded lawmakers to approve a “historic” bill to limit greenhouse-gas emissions as part of intensifying lobbying efforts for a vote in the U.S. House that could come today.

Obama yesterday promoted the bill in a brief public statement outside the Oval Office and, in a private session at the White House, pressed undecided Democratic House members to back it. He also made calls to lawmakers.

Republicans and some business groups worked to drum up opposition to the 1,200-page legislation, which they labeled a “national energy tax.”

Obama, in his public comments, called the measure “absolutely critical” to ensure a clean-energy economy that would help the U.S. “be the nation that leads the 21st century global economy.” He also predicted “a close vote” on it.

The House is set to begin debate this morning and could vote later in the day on the bill, called the American Clean Energy and Security Act. The so-called cap-and-trade measure would create a market for trading pollution permits as a way to curb the emissions that many scientists say contribute to climate change. It calls for the U.S. to reduce its greenhouse- gas emissions by 17 percent from 2005 levels by 2020.

The bill’s chief sponsors, Democratic Representatives Henry Waxman of California and Edward Markey of Massachusetts, agreed during the past month to reduce its environmental mandates and increase aid to polluters, including coal-fired power plants, to help companies meet the measure’s clean-air regulations. The two made the compromises to build broader support for the bill after the House Energy and Commerce Committee, which Waxman heads, passed it on May 21.

Added Benefits

The legislation will pass, House Majority Leader Steny Hoyer said. The bill will get about 218 votes, Hoyer, a Maryland Democrat, said in a Bloomberg Television interview today.

Negotiators reached a breakthrough earlier this week with an accord to give farmers and coal-fired electric utilities added benefits. That hasn’t been enough, though, to guarantee the support of all lawmakers from rural districts.

The American Farm Bureau, the nation’s largest farm lobby, opposes the bill, as does a coalition of food processing groups including the National Chicken Council and the National Meat Association.

Agriculture Committee Chairman Collin Peterson, a Minnesota Democrat, announced his support for the bill this week after the negotiations with Waxman and Markey. Still, he predicted that the 28 Democrats who serve on his panel would end up split on the measure.

‘Not Perfect’

In all, more than two dozen House Democrats remained undecided as of late yesterday. Former Vice President Al Gore, who won a Nobel prize for his work on climate change, called lawmakers from his Nashville home on behalf of the bill after canceling a planned trip to Washington to lobby for it at a news conference.

AFL-CIO chief lobbyist Bill Samuel said the union group supported the bill, even as he called it “not perfect.”.

“We look forward to working with Congress to improve this landmark legislation,” Samuel wrote in a letter delivered to lawmakers last night.

Critics, including billionaire investor Warren Buffett, head of Omaha, Nebraska-based Berkshire Hathaway Inc., say the plan would increase the price of energy.

U.S. Chamber of Commerce Executive Vice President Bruce Josten urged lawmakers to vote against it because he said it wouldn’t ensure development of enough renewable energy sources to make up for the required reduction in fossil-fuel emissions.

“Instead, it would impose 397 new regulations and 1,060 new mandates on the American public,” Josten wrote in a letter sent yesterday.

‘Ridiculous Tax’

House Republican Leader John Boehner of Ohio called the legislation “job killing” and said it would “punish” Americans with a “ridiculous tax.”

Representative Eric Cantor of Virginia, the second-ranking House Republican, called the measure a “national energy tax” on households and small businesses. The measure would lead to “the loss of millions of jobs,” he said.

Obama said cleaner energy and economic growth aren’t contradictory. Addressing opponents and undecided lawmakers, he said, “We cannot be afraid of the future, and we can’t be prisoners of the past.”

To contact the reporter on this story: Lorraine Woellert at lwoellert@bloomberg.net.

Last Updated: June 26, 2009 09:38 EDT