In this composite image, British Prime Minister Tony Blair [Images] yawns before attending a round table summit meeting at G-8 on June 7 in Heiligendamm, Germany [Images].

This will be Blair's last G-8 summit, as he prepares to leave office on June 27 after being in power for a decade.

Meanwhile, in a landmark move to fight climate change, the G-8 developed countries on Thursday agreed to halve dangerous greenhouse gas emissions blamed for global warming, by 2050.