US Chairman of the Federal Reserve Ben Bernanke arrives for the G20 finance Minister's summit at the Treasury in Westminster, London, Saturday Sept. 5, 2009. British Prime Minister Gordon Brown called on Group of 20 leaders to make a strong and clear commitment to continued efforts to boost global growth, saying Saturday that the world economy is at a "critical juncture." Addressing finance officials from the G-20 rich and developing countries at the start of their talks here, Brown warned against "complacency or overconfidence" in the face of mounting signs of at least a modest economic upturn. (AP Photo/Dominic Lipinski, Pool)