President Bush on Wednesday hailed the G-8 summit's move to coalesce behind a global climate change strategy, saying he hopes it will ultimately help nations to be "good stewards of the environment."

"In order to address climate change, all major economies must be at the table, and that's what took place today," Bush said in a statement to reporters at the conclusion of the summit of leading industrialized nations — a meeting that he said also moved ahead on international free trade and combating hunger and disease around the world.

Bush, who early in his presidency disputed many leading scientists' notions about climate change and global warming, said he backs the G-8's declaration that greenhouse emissions should be slashed by 50 percent by the middle of the century.

"We made clear, and the other nations agreed, that they must also participate in an ambitious goal," he said, "with an interim goal, with interim plans to enable the world to successfully address climate change. And we made significant progress toward a comprehensive approach."

Bush reiterated his position that much substantive progress will hinge on further development of clean energy technology and said developing nations will need assistance in this area so they can become "good stewards of the environment."

The president praised his fellow summit leaders for their work not only on climate change but also on steps to advance the so-called Doha Round of negotiations on opening markets to free trade and their cooperation with U.S. efforts to help poor nations combat disease and food shortages.

The G-8 nations are the U.S., Britain, Germany, France, Italy, Canada, Japan and Russia.

In the departure statement in which he fielded no questions from reporters, Bush sought to frame his last G-8 as a glowing success.

He did not address criticisms that emerged about the G-8's positions, such as that the group's stance on reducing global warming does not go far enough or fast enough. Rather, he said the world's richest countries had moved to improve to the daily life of millions of people. He cited new agreements on fighting disease, protecting the environment and promoting development.

In doing so, the president said, "We served both our interests as Americans, and we've served the interests of the world."

Among other achievements Bush touted, he said the G-8 nations had agreed to produce clear, transparent reports on whether they are keeping their promises of humanitarian aid to poverty-stricken Africa.

He said such accountability will keep politicians from talking big but not following through.

"I've always believed that to whom much is given, much is required," Bush said. "The nations sitting around the table have got much, and I think we're required to help those who don't."

And on the sidelines of the summit, he had one-on-one meetings with several world leaders, including China's President Hu Jintao. He assured Hu that he is excited about going to the Beijing Olympics later this summer, and Hu responded that he was grateful the United States had not politicized the event because of the crackdown in Tibet.