WELLS, Maine?—?President Bush, who withdrew from the Kyoto environment accord, sought to counter critics who accuse him of trying to reverse decades of environmental progress in an Earth Day appearance at a wetlands area near his family's Maine estate.

After donning a navy windbreaker and hiking boots to trudge through a coastal salt marsh, the president claimed credit for what he called "some of the most important antipollution policies in a decade."

"Since 2001, the condition of America's land, air, and water has improved," he told an audience of about 200 people.

But even as Bush announced a goal of creating or preserving 3 million wetland acres over five years, alumni of the first Earth Day in 1970 criticized him for ignoring basic environmental issues such as economic sustainability and the growing world dependence on fossil fuels, including Middle Eastern oil.

"There's a disaster coming," warned Earth Day founder Gaylord Nelson, 85, a former U.S. senator from Wisconsin. "The president and Congress should lead us toward a goal of environmental and economic sustainability. But the exploiters dominate opinion. I've never seen anything like it."

"The environment is a cutting issue for a lot of people, and that's going to hurt Bush," said Sandy Maisel, political science professor at Colby College in Waterville, Maine.

As a political issue, wetlands appeals to a key Republican constituency of sportsmen who have met Bush twice since last November to register concerns about the loss of hunting and fishing areas to development.

A recent Gallup poll showed a 46 percent disapproval rating for Bush on the environment compared to a 41 percent approval rating. The poll had a three percent margin of error.

After Bush spoke, former Environmental Protection Agency head Carol Browner told CNN that the president had redefined wetlands so that nearly half of U.S. wetland areas were no longer protected by the EPA, which was created in response to the first Earth Day.

Environmentalists and Democrats, including presidential candidate John Kerry, say Bush has damaged air, water, and land quality by relaxing EPA enforcement of pollutants such as mercury emissions from power plants.

In February, scientists including 20 Nobel laureates issued a statement accusing the Bush administration of deliberately distorting scientific findings to further its political aims.

Critics also said Bush's wetlands message allowed the president, a former Texas oil man, to skirt the weightier issue of rising energy consumption.

"If we had a president who wanted to solve environmental problems, and he brought in advisers and said, 'What requires my help to fix?' The answer would be energy," said Sierra Club executive director Carl Pope, whose group has battled the White House to the Supreme Court in hopes of identifying members of the secret task force that formulated Bush's energy policy.

What many environmentalists want is a major national initiative akin to the Apollo space project of the 1960s to drive development of new fuels and technologies and solve a range of problems from air and water quality to health.

Bush administration officials defended the president's environmental record, citing proposed tax incentives for solar energy and hybrid-fuel vehicles. An official said the president had also tightened fuel efficiency standards for gas-guzzling SUVs from 20.7 mpg to 22.2 mpg .

"At least they can say that's more than the Democrats proposed under Clinton," said independent presidential candidate Ralph Nader.