The prime minister has said there is a "tremendous opportunity" for action on climate change, following a meeting with German Chancellor Angela Merkel.
Mr Blair said they were "on the same lines" on key issues
Tony Blair said G8 leaders had a chance to create a new framework, for when the Kyoto Protocol runs out in 2012.
But he said the next few months were crucial if a deal was to be secured at the G8 meeting in Heiligendamm in June.
Ms Merkel, whose country is hosting the G8 presidency, said climate change was one of humanity's biggest challenges.
Speaking after the meeting in Berlin, Mr Blair said the next few months, which will be his last in office, were "absolutely crucial" for climate change and other priorities like the Middle East peace process.
He said Britain and Germany were "very much on the same lines" on key issues.
Both stressed the need for progress on the Middle East peace process, which Mr Blair said was at a "delicate moment", and on the environment.
Mr Blair said there was widespread agreement on the threat posed by climate change, and demand from people across the world for their governments to do something about it.
"This is the right moment to look at how we protect our environment and grow sustainably, but also make sure we have got secure supplies of energy in the years go to come," he said.
But he said it was vital that any post-2012 process was supported by the US, China and India - as well as those who had signed up to Kyoto.
Ms Merkel said details of a climate change deal would be worked out during a conference in May - to be put to the leaders of the G8 countries in the summer.
It would include a CO2 reduction goal, an international system of carbon pricing to boost the development of greener technology, and ways of giving emerging economies like China and India access to such developments.
She also said the aim was for Europe to reduce greenhouse gases by 30% and increase the share of energy from renewable sources by 20%, by 2020.
"We think that the time has come to work with all our energy and ambition," she said.
"We think this is one of the great challenges that mankind faces in our time and one of the great challenges that mankind can do most on if it acts together and in concert."
Mr Blair, who has said he will resign as prime minister by September, was asked how much he could hope to achieve when he had only a few months left to serve.
He replied: "As much as I can".