WASHINGTON — President Bush sought last night to counter criticism that he has failed to do enough to tackle global warming and energy security as he unveiled a 10-year plan to slash U.S. gasoline consumption by 20 percent.

He proposed a dramatic expansion in the use of alternative fuels like ethanol to offset the cut in gasoline use, and he asked for wider power to toughen fuel-economy standards for cars.

If initial assessments are any guide, the president has more persuading to do. Critics said that while his plan had many good elements, it either does not go far enough or might not be practical in some cases.

As a result, the global-warming issue in Congress and the country seems destined to grow even hotter as a Democratic-controlled Congress considers whether to slap an overall cap on carbon dioxide emissions that contribute to warming of the planet. On Monday, several corporate executives from blue-chip companies backed such an idea.

Even so, Bush presented a proposal that goes far beyond anything else he has previously offered to address what he called America's addiction to oil. The White House said the plan would halt the projected growth of carbon dioxide emissions from cars, light trucks and sport utility vehicles within 10 years.

"America is on the verge of technological breakthroughs that will enable us to live our lives less dependent on foreign oil," Bush said. "These technologies will help us become better stewards of the environment — and they will help us to confront the serious challenge of global climate change."

His proposal signaled that climate change has joined energy security as a monster political issue, and that political leaders now may be prepared to take more extensive action.

"As the global warming issue heats up across America, the president's position on global warming is beginning to thaw," said Larry Schweiger, president and chief executive of the National Wildlife Federation.

But he and other supporters of a plan to cap greenhouse-gas emissions said Bush needs to go further. Richard Rosenzweig, chief operating officer of Natsource, a firm that manages buying and selling of clean-energy credits, said he expected to see such a mandatory program "in a couple of years."

Bush proposed that the amount of ethanol and other alternative fuels used in gasoline blends be set at 35 billion gallons in 2017, up from the 7.5 billion gallons required in 2012. This would be enough to displace 15 percent of projected annual gasoline consumption by 2017, the White House said.

Many members of Congress, including Sen. Barack Obama, D-Ill., have offered similar plans to require that America put more emphasis on cleaner-burning alternative fuels such as ethanol.

But energy experts said that while the goal is laudable, it would require that automobile manufacturers build many more cars that are equipped to handle gasoline blends that have a higher alternative-fuel content. For example, only a small number of autos in the country can burn fuel containing 85 percent ethanol.

"The real questions are going to be whether we are going to have the infrastructure to move the fuels or have the vehicles to use the fuels," said Kateri Callahan, president of the Alliance to Save Energy.

"Producing 35 billion gallons of ethanol a year would require putting an additional 129,000 square miles of farmland — an area the size of Kansas and Iowa — into corn production, which is not very likely," said Philip Clapp, president of the National Environmental Trust.

In another energy initiative, the president asked Congress for authority to "reform" fuel-economy standards for cars, even though congressional critics said Bush now has all the power he needs.

The plan would enable the government to set fuel-efficiency standards for cars based on their size, in the same way that it can set such standards for light trucks, the White House said.

The administration said these tougher corporate average fuel economy standards would reduce gasoline consumption by 5 percent, or 8.5 million gallons annually, by 2017.