Updated

Chief executives of 10 major corporations urged Congress on Monday to require limits on greenhouse gases this year, contending voluntary efforts to combat climate change are inadequate.

The call for immediate action came on the eve of President Bush's State of the Union address in which he is expected to reiterate that the industry on its own is making progress in curtailing the growth of heat-trapping emissions without the need of government intervention.

But the executives and leaders of four major environmental organizations said in a letter to Bush that mandatory emissions caps are needed to reduce the flow of carbon dioxide and other heat-trapping gases into the atmosphere.

"We can and must take prompt action to establish a coordinated, economy-wide market-driven approach to climate protection," the executives, part of a coalition called the U.S. Climate Action Partnership, said in a letter to the president.

The executives, representing major utilities, aluminum and chemical companies and financial institutions, said the cornerstone of climate policy should be an economy-wide emissions cap-and-trade system.

Members of the group include chief executives of Alcoa Inc. (AA), BP America Inc. (BP), DuPont Co. (DD), Caterpillar Inc. (CAT), General Electric Co. (GE), and Duke Energy Corp.

At a news conference, the executives said that mandatory reductions of heat-trapping emissions can be imposed without economic harm and would lead to economic opportunities if done across the economy and with provisions to mitigate costs.

Many of the companies already have voluntarily moved to curb greenhouse emissions, they said. But the executives also said they do not believe voluntary efforts will suffice.

"It must be mandatory, so there is no doubt about our actions," said Jim Rogers, chairman of Duke Energy. "The science of global warming is clear. We know enough to act now. We must act now."

Eileen Claussen, president of the Pew Center on Global Climate Change, said the group intends to push the issue in Congress, urging lawmakers to address climate change as soon as possible. She said she expects other major corporations to join in the call.

Fred Krupp, president of Environmental Defense, a member of the alliance, called the executives' support "a game changer" in the debate over climate change. "We are asking Congress to not wait for a new administration and not wait for the presidential debates," Krupp said.

In the letter, the executives urged Congress to significantly reduce greenhouse gas emissions. The legislation should cut these releases 10 percent below today's levels within a decade and at least 60 percent by 2050, according to the action plan. Releases of carbon dioxide, the principal heat-trapping gas, has been increasing an average of 1 percent a year.

At his daily briefing, White House press secretary Tony Snow dismissed any call for mandatory, economy-wide carbon caps to deal with climate. He acknowledged there's been some talk about such caps, "but they are not part of the president's proposal."

The first days of the new Democratic-controlled Congress have seen a rush of legislation introduced to address climate change, all of which have some variation of a cap-and-trade approach to dealing with climate change.

Among those pushing cap-and-trade climate bills are two leading presidential aspirants, Sens. Barack Obama, D-Ill., and John McCain, R-Ariz.

Essentially such a mechanism would have mandatory limits of greenhouse gas emissions, but would allow companies to trade emission credits to reduce the cost. Companies that can't meet the cap could purchase credits from those that exceed them or in some case from a government auction.

Also signing the letter to Bush were the executives of Lehman Brothers, PG&E Corp., PNM Resources, FPL Group and four leading environmental organizations.