WASHINGTON — President Bush said yesterday America should halt the rise in its greenhouse gas emissions by 2025, as he sought to set boundaries for global warming initiatives under consideration by Congress and major industrialized nations. But the calendar leaves him little time and, critics said, little prospect of influencing the debate. All the presidential candidates who want to replace him favor stronger action.

To reach his goal, the president said America would need to slow the growth in emissions from power plants in the next 10 to 15 years and then begin to reverse that growth.

As he has in the past, Mr. Bush put greatest reliance on using technological advances to reduce the release of carbon dioxide and other gases, which are released when coal, petroleum products, and other fossil fuels are burned and which are widely blamed for rising global temperatures. He gave no support to calls for mandatory limits on emissions.

A confluence of three events has pushed Mr. Bush to move haltingly toward a more aggressive global warming policy: The 17 major industrialized nations that give off 85% of greenhouse gases are meeting in Paris to develop a new international attack on global warming, pressure is growing to find legislative remedies, and courts are pushing government agencies to act under the requirements of several environmental laws.

“The train is moving toward legislation that will control heat-trapping bases in the U.S.,” David Sandalow, who led the Clinton administration efforts to negotiate international climate change agreements, said. But, he added, Mr. Bush was offering “a weak goal in place of strong legislation.”

To one degree or another, Senator McCain, the presumptive Republican presidential nominee, and the two candidates for the Democratic presidential nomination, Senators Clinton and Obama, favor setting limits on emissions. The most widely discussed system would cap emissions and allow companies and others that emit gases below the limits to sell credits to those who are unable to meet the targets. A bill sponsored by Senators Lieberman, an Independent of Connecticut, and Warner, a Republican of Virginia, would seek to reduce greenhouse gas emissions by mid-century to 66% below 2005 levels, while allowing companies to trade pollution rights. House leaders are also drafting legislation.

Mr. Bush intentionally made no mention of the so-called cap-and-trade system, which has been used for more than a decade in the fight against acid rain. He has opposed the program in the past, but a senior White House official said he was not ruling it in or out.

Proponents took heart because he did not express opposition in his speech in the White House Rose Garden. An environmental economist at Harvard, Robert Stavins, said any step Mr. Bush took toward addressing the issue “is a step in the right direction for this administration,” which he said has been “disengaged.”