Leaders of the G8 nations have agreed to a compromise deal on tackling climate change, German Chancellor Angela Merkel has said.
"We agreed... that CO2 emissions must first be stopped and then followed by substantial reductions," she said.
Reports said the leaders agreed to hold talks on a replacement to the Kyoto Protocol within a UN framework.
Mrs Merkel had been pushing for a 50% cut in emissions by 2050. The US had resisted calls for targets to be fixed.
She said G8 leaders had agreed to consider her target, but there was no suggestion that a final agreement would include any mandatory commitment to major emissions cuts.
Allow me to outline what I see as the problem. We know that global warming is real, and that human-caused burning of fossil fuels is largely driving it. All the G8 governments were part of the IPCC process, which made those conclusions, and they all agreed to those findings.
There's wide scientific consensus that if the global temperature rises more than two degrees Celsius above preindustrial levels, then we can forget about trying to control climate change.
We also know that the amount of CO2 equivalent in the atmosphere comes to 425 parts per million (about 380 ppm of that is CO2), and that if it gets over 450 parts per million, we're in big trouble.
The only practical way to stop the GHG levels from rising are to stop them from getting into the atmosphere in the first place; we have no human-originated technology for removing them. Once CO2 gets into the atmosphere, it stays there for up to 200 years.
The longer we put off dealing with the issue, the steeper the cuts will have to be to keep the concentration from reaching dangerous levels.
Success has been declared even though the world's top leaders won't agree to holding the global temperature rise to two degrees or commit to deep enough or quick enough emissions cuts to prevent that from happening.
Question: What would failure look like?
The headline on the Reuters story on globeandmail.com is: Climate experts slam G8 deal on emissions
Now, some did try to look on the sunny side:
The summit in Germany made progress by agreeing to try to launch talks in Bali, Indonesia, in December aimed at reaching a deal in 2009 on a pact that would extend the U.N.'s Kyoto Protocol for combating global warming beyond 2012.
"I think it's a very positive outcome. It augurs very well for the conference of parties in Bali," said Yvo de Boer, the head of the UN climate change Secretariat in Bonn.
"But bear in mind that this is a G8 conclusion and there are one or two other countries in the world who have to commit to a launch in Bali," he said. Other big emitters include China, India, Brazil and Indonesia. ...
Others saw progress after President George W. Bush agreed that his plan to convene talks among the top 15 emitters of greenhouse gases would feed into the UN process rather than set up a rival track.
"I think that now the United States with the present administration has got on the bandwagon. This is an irreversible step," said Hans Joachim Schellnhuber, head of a top German climate research institute.
"We are seeing that the United States is resuming global leadership on climate protection and I am sure this will be amplified and accelerated by the next administration," he said.
The BBC's environment analyst Roger Harrabin had an upbeat take: G8 climate deal signals a breakthrough. An excerpt:
It is full of political wriggle-room, it does not send clear signals for business investment and it offers no certainty that the climate will be saved from irreversible damage - but for all these failings, the G8 summit looks like a breakthrough in the long Euro-American stand-off over climate policy.
In the words of one European policy adviser: "While Europe has been itching on the starting blocks for the past decade, Bush has been sulking in the changing room. At least he is now on the track."
European and US positions on climate change still differIt is certainly inconceivable even a few months ago that US President George W Bush would have signed up to such a stream of resonant phrases about the importance of early action to tackle climate change.
He was even persuaded to put his name to a statement promising to strongly consider at least a halving of global emissions by 2050.
Previously it has been hard to engage the White House in any conversation that touched on the notions of limits.