Group of Eight leaders have agreed on a plan calling for greenhouse gas emissions to be cut in half by 2050, German Chancellor Angela Merkel said Thursday.

Few details have been released, but G8 leaders including Prime Minister Stephen Harper have called the plan a good first step toward averting dangerous climate change.

"We agree that we need reduction goals -- and obligatory reduction goals," said Merkel, who shepherded the deal as chair of the G8 summit in northern Germany.

The language of the declaration, however, falls short of an iron-clad agreement and contains no hard targets. It says the world's biggest emitters of greenhouse gases should "consider seriously" following the European Union, Canada and Japan in seeking to cut emissions.

"Taking into account the scientific knowledge as represented in the recent (Intergovernmental Panel on Climate Change) reports, global greenhouse gas emissions must stop rising, followed by substantial global emission reductions," says a passage from the declaration published on the G8 website.

"In setting a global goal for emissions reductions in the process we have agreed today involving all major emitters, we will consider seriously the decisions made by the European Union, Canada and Japan which include at least a halving of global emissions by 2050."

Harper said the leaders agreed they need mandatory targets for emissions reduction. But he added that the previous Liberal government set unrealistic climate goals for Canada and that a "new," more practical plan is still being worked out.

Merkel said the plan was the result of many rounds of negotiations on climate change. She had wanted G8 leaders to agree to binding reductions, but that request was opposed by U.S. President George Bush.

The president had suggested the world's top 15 polluting countries meet and set long-term goals, but decide for themselves how much to do toward meeting it.

Harper said the U.S. was very clear it wouldn't agree to any hard targets unless it sees the entire world come behind that concept.

"Obviously our position is a little different because we proceeded with our own targets, but I think (the deal) is a major step forward and if we can keep the momentum going, I think we're moving in the right direction," Harper said.

But he added: "We should not kid ourselves. I think we should be a little bit restrained in being a little too high on our pedestal here.

"We committed to targets without thinking those targets through 10 years ago, and then are unable to reach them. So when others say we want a fulsome discussion before we actually determine what reasonable targets are, I think that's something we have to be flexible on."

'Watered-down' deal

Opposition politicians in Ottawa, meanwhile, are calling the G8 agreement on climate change a "watered-down" deal.

Liberal Leader Stephane Dion said the plan doesn't include any clear targets for cutting GHGs, and accused Harper of failing "Canada and the world.''

"The bar has been set so low that this so-called agreement does not even reflect what is really necessary to fight against climate change," said Dion during question period in Parliament, adding that the declaration fails to recognize the "scientific imperative" to limit temperature increases to 2 degrees Celsius in the next century.

Experts say hard targets to reduce emissions by 50 per cent are needed to prevent that temperature rise.

"The prime minister and the world has to do at least the minimum. Because this represents a minimum, should the government not admit once and for all that all they want to do is the minimum, the minimum for Canada and the world?" said Dion.

NDP Leader Jack Layton accused Harper of helping Bush convince other G8 countries to accept "bad ideas" on the environment.

But Tory Government House leader Peter Van Loan said today's G8 declaration shows Canada is now a leader in the world on the environment, after years of neglect.

And Environment Minister John Baird stressed that Canada's efforts to stave off climate change were acknowledged on the world stage today.

"For the first time ever, we have a plan to reduce greenhouse gases, and the leaders are seeing that for the first time," Baird told Mike Duffy Live in a phone interview from Heiligendamm.

"Europe has been a real leader in this and Europe has pushed strongly for real action, and Canada's very much on the same page as many European countries."

Talks with Putin

Merkel is hosting the G8 meetings that officially got underway Thursday in Heiligendamm.

Key issues at the talks are combating climate change and aid for Africa.

In the last few days, however, tension between Russia and the U.S. over an American proposal to build missile defense bases in Russia threatened to divert attention from the other issues.

Russian President Vladimir Putin has slammed the proposed U.S. anti-missile bases in Europe, saying earlier this week that he would aim Russian ballistic and cruise missiles at European targets if the U.S. went ahead with the plan to build the bases. However, Reuters reports that Putin said Thursday Russia and the U.S. would "have no problems" if they co-operated closely on a missile shield.

In his only public statement on the issue, Harper assured Putin that there is nothing to fear about the U.S. plans.

Harper was set to press Putin on his country's democratic record during a meeting Thursday at the G8 Summit, Canadian officials confirmed.

At the beginning of the meeting -- the only part open to journalists -- Putin broke the ice by congratulating Canada on its victory at the recent world championships in Russia.

Harper thanked Putin and made no reference to democratic record issues he was expected to raise during the meeting, only saying he wished to discuss "a number of other issues."

Putin said he wanted to talk about economic co-operation.

The topic of Russia's democratic record will be raised after the recent beatings and arrests of anti-government protesters and the deaths of some of Putin's harshest critics, a senior official told The Globe and Mail Wednesday.

There have been numerous incidents in Russia -- including journalists shot in the head or dropped from high buildings -- that have raised concern among the international community.

Also, a former Russian spy that was poisoned blamed Putin in a letter written on his death bed.

The official told The Globe that Russia, as a member of the G8, is required to be a standard-bearer for good government.

"I think Russia's made an enormous amount of progress in recent years and I think we'd want to make sure that the President is aware of our hope that progress will continue," the official said.

The two leaders will meet for about 40 minutes Thursday afternoon.

U.S. President George Bush will also meet with Putin today and has said that he hopes to convince him that the issue is not one "to be hyperventilating about."

Meanwhile, a train carrying a group of Canadian journalists, including CTV's Parliamentary Correspondent Graham Richardson, into Heiligendamm was blocked by protesters Thursday.

As a result, the group was forced to access the site by boat from the Baltic Sea.

The summit site is surrounded by security, including military boats, choppers and even an underwater fence.

With files from The Canadian Press