( AFP )- Tony Blair on Saturday urged the world's heaviest polluters including the United States and China to agree to binding emissions cuts, saying failure to act on global warming would be "unforgivably irresponsible."
The former British prime minister is heading a new team of experts tasked with bridging the gaps in slow-moving negotiations to draft a successor to the Kyoto Protocol by the end of next year.
"We have reached the critical moment for the decision on climate change," Blair told a meeting of senior officials from the world's top 20 greenhouse gas emitters in suburban Tokyo.
"Even on the mildest application of the precautionary principles, failure to act on climate change now would be deeply and unforgivably irresponsible," he said.
The weekend meeting is meant to pave the way for July's summit of the Group of Eight wealthy nations on the northern Japanese island of Hokkaido.
"The G8 summit this year at Hokkaido be the date with destiny on the issue," said Blair, who stepped down last year after a decade as prime minister.
"The question now is , can we take it further? Can we agree on a binding global target of at least a 50 percent cut in emissions? Can we spell out the principles of a deal to do?" Blair said.
Last year's summit of the Group of Eight -- Britain, Canada, France, Germany, Italy, Japan, Russia and the United States -- agreed to seriously consider a target of 50 percent cuts in emissions by 2050.
But there was no binding commitment and the base year for the reductions was ambiguous.
The United States has shunned the Kyoto Protocol, arguing that it is unfair by making no demands of fast-growing emitters such as China and India.
All sides, however, agreed in talks in December in Bali to be part of the negotiations to draft a successor to the Kyoto treaty, whose obligations run out at the end of 2012.
The next round of negotiations on a post-Kyoto deal start at the end of the month in Bangkok.
Blair in 2005 launched the Group of 20 initiative on the environment which includes Group of Eight members as well as emerging economies such as Brazil, China and India.