The leaders of the Group of Eight industrial nations look set to agree an accord to combat climate change at their summit this week, averting a rift between the US and France over global warming and intensifying pressure on China and India to curb greenhouse gas emissions.

As Tony Blair prepares to host the G8 leaders at the gathering in Gleneagles, the prime minister is on the brink of brokering a global agreement on climate change, one which explicitly recognises that science compels the world to act to contain greenhouse gases.