HEILIGENDAMM, Germany — Group of Eight leaders, including US President George W. Bush, agreed yesterday to call for “substantial global emissions reductions” to fight global warming, and cited a goal of a 50 percent cut by the middle of the century.European leaders hailed the deal as progress in the wrangling between Europe and the United States over global warming, with the Europeans pushing mandatory cuts and the US resisting.

German Chancellor Angela Merkel, who shepherded the deal as chair of the G-8 summit in Heiligendamm in northern Germany, called it “very great progress and an excellent result.”

With Bush resisting concrete cuts, it had appeared Merkel’s summit would fall short of her goal of a substantial deal on climate change at the G-8, which is Germany, the United States, Russia, Britain, Italy, France, Canada and Japan.

“We agree that we need reduction goals — and obligatory reduction goals,” she said.

But the language of the declaration appeared to fall well short of a full commitment. It called for the countries to “seriously consider” following the European Union, Japan and Canada in seeking to cut emissions in half by 2050.

“No one can escape this political declaration; it is an enormous step forward,” she told reporters.

Britain’s Prime Minister Tony Blair was asked if there was “wiggle room.” He said the final result would depend on upcoming UN climate change negotiations.

“However, there is now a process to lead to that agreement, and at its heart is a commitment to a substantial cut,” he said, calling the deal “a major, major step forward.”

On the first full day of the summit, Bush and Russian President Vladimir Putin discussed the dispute over a US proposal to put a missile defence system in eastern Europe, and Bush waxed nostalgic about this last summit with friend and ally Blair, who leaves office June 27.

“This is the last meeting I will have with him as prime minister,” Bush said. “I’m sad about that.”

French President Nicolas Sarkozy, making his G-8 debut, said he and Putin discussed the future of Serbian’s Kosovo province. The US and key European nations back supervised independence for the predominantly ethnic Albanian Serbian province but Russia, Serbia’s traditional ally, objects.

“We must avoid going into conflict straight away,” Sarkozy said, suggesting to Putin that Belgrade and Pristina be given six months to work out a deal; if there is no agreement, then the UN plan would be applied.

A Putin spokesman said only that there was “some movement” on the matter.

Outside the summit site, police used water cannons to turn back several thousand demonstrators who rushed the (seven-mile) fence around the summit site of Heiligendamm, and police boats chased down inflatable boats from the environmental group Greenpeace that entered the security zone on the Baltic Sea.

The meeting also produced an unexpected proposal from Putin, who said he would drop his opposition to a US missile defence system if it made use of a Russian-leased radar station in Azerbaijan. Currently the plan is to put 10 interceptor missiles in Poland and a radar in the Czech Republic to guard against a potential future threat from Iran.

Bush did not mention the alternative presented by Putin. He only said Putin “had some interesting suggestions.”

On climate change, Bush’s national security adviser, Stephen Hadley, said the ideas in the G-8 declaration are in the president’s proposal.

“The president made clear last week that we accepted the principle of a long-term goal,” Hadley said during a telephone briefing with reporters. “I think it’s very consistent with some ideas the president had last week.”

The document endorses the UN framework for climate change talks, a key demand from Merkel. But it did not commit to Merkel’s target under which global temperatures would be allowed to increase by no more than two degrees Celsius (3.6 degrees Fahrenheit) before being brought back down. Experts say the 50 percent emissions reduction is needed to meet that goal.

Bush has opposed mandatory cuts and maintains that developing nations such as China, India and Brazil must be included. He also says economic growth cannot be sacrificed for progress on climate change.

Climate talks will begin within the UN framework with a meeting of environment ministers at a UN climate change conference in Bali, Indonesia, in December.

The conference will seek to come up with a successor agreement to the 1997 Kyoto Protocol, which commits industrial countries to cut emissions by five percent below 1990 levels. The US signed the treaty but did not ratify it.

The top UN climate official said the agreement was “very important progress” because it committed the countries to come up with a successor to the Kyoto Protocol by 2009.

“The important thing is to get the negotiations going, rather than to decide what the outcome is going to be,” said Yvo de Boer, executive secretary of the UN Framework Convention on Climate Change.

“I know Chancellor Merkel is declaring victory, but in fact President Bush has shut the door in the faces of the other seven leaders at the table,” said Philip Clapp, president of the US-based National Environmental Trust, pointing to the “seriously consider” phrase.

“That is a far cry from the United States having signed up to any such reductions,” he said.

Clapp said that the agreement showed progress among the other countries in reaching a consensus that could be taken up by the next US president after Bush leaves office in early 2009.