Sens. John McCain (R-Ariz.) and Joseph I. Lieberman (D-Conn.) will unveil a plan this week to require all U.S. power plants and industries to reduce their emissions of carbon dioxide and other greenhouse gases, setting the stage for a conflict with the Bush administration and the new chairman of the Senate Environment and Public Works Committee.

McCain, chairman of the Commerce, Science and Transportation Committee in the Senate that convenes today, has scheduled a hearing for Wednesday and intends to send legislation to the Senate floor later this year, aides said.

But the Bush administration and Sen. James M. Inhofe (R-Okla.), the new chairman of the Environment and Public Works Committee, staunchly oppose mandatory limits on greenhouse gases, favoring a voluntary approach instead. Inhofe has said his committee would put off consideration of major air pollution legislation this year, while lawmakers focus on highway spending reauthorization and legislation authorizing Army Corps of Engineers water projects and administrative practices. His committee has primary jurisdiction over Environmental Protection Agency regulations.

"We have had no communications with the Commerce committee about their hearing, and certainly our position is that any bill dealing with climate change would have to go through the Environment and Public Works Committee," said Gary Hoitsma, a spokesman for Inhofe.

"We don't see eye-to-eye with the thrust of the bill McCain and Lieberman are pushing, and this is not a priority for the administration."

A McCain aide said that while Inhofe's committee has a jurisdictional claim on EPA regulatory matters, "nevertheless, a lot of what we're trying to do [in the Commerce committee] affects other things, including transportation and scientific research."

The attempt by McCain and Lieberman to bypass the Environment and Public Works Committee on a politically sensitive environmental issue could provide an early test of the leadership skills of new Senate Majority Leader Bill Frist (R-Tenn.). An aide to Frist said yesterday "it's a little early" to say how the majority leader will weigh in, but added that Frist is generally supportive of the president's approach to global warming.

The McCain-Lieberman proposal would establish a nationwide cap on emissions of carbon dioxide and other heat-trapping gases that contribute to the Earth's rising temperature. Under the bill, all major energy, industrial and transportation sources of the six major greenhouse gases would have to limit their emissions to 2000 levels by 2010 and 1990 levels by 2016.

The bill would establish a trading system that would allow utilities and plants with excessive emissions to buy credits from more efficient companies that have reduced emissions beyond their targets. A similar system has operated for years, under the Clean Air Act, to limit the threat of acid rain.

The bill is a product of prior hearings held by McCain's committee and consultation with the Pew Center on Global Climate Change and some industry representatives.

The proposal is less stringent than the terms of the 1997 Kyoto Protocol, which is aimed at mandatory reductions in greenhouse gas emissions.

It's more in line with the unfulfilled goals of the 1992 Framework Convention on Climate Change, or Rio treaty, which was signed by President George H.W. Bush.

Fred Krupp, president of Environmental Defense, said the McCain-Lieberman proposal is "an historic breakthrough" that provides the first bipartisan blueprint of a comprehensive, economy-wide national policy for cutting emissions of heat-trapping gases that threaten to disrupt Earth's climate. Jeremy Symons of the National Wildlife Federation said recent studies documenting the adverse effects of climate change on plants and animals "are sounding the alarm that global warming is already altering our environment at a dangerous pace, but all that President Bush has done is hit the snooze button."

Early in his term, Bush disavowed the Kyoto Protocol, saying it would harm the U.S. economy. He announced an alternative approach including further research into climate change and economic incentives to encourage voluntary reductions of emissions. The administration sponsored a conference last month highlighting many of the unanswered questions about global warming.

While most senators agree with Bush that the Kyoto protocol is a bad deal for the United States, many sharply disagree with his refusal to negotiate an alternative pact with U.S. allies.

Last August, the Senate Foreign Relations Committee unanimously voted to urge Bush to return to the bargaining table with specific proposals for a new binding international global warming treaty.

"President Bush is now facing an emerging split in his own party on global warming," said Philip Clapp, president of the National Environmental Trust. "Increasing numbers of Republican senators -- and not only the moderates from the Northeast but senators from agricultural states in the Midwest -- recognize this is an issue the Republican Party cannot politically afford to ignore."