British Treasury chief Alistair Darling, Left, walks with an unidentified official at the venue of the G20 Finance Ministers meeting in St. Andrews, Scotland Saturday Nov. 7, 2009. Rifts among the world's top financial ministers and central bankers from the Group of 20 rich and developing nations, are reported to be threatening attempts to secure future global growth and break a deadlock over the cost of fighting climate change. (AP Photo/Martin Cleaver)AP – British Treasury chief Alistair Darling has urged the world’s top finance officials to reach an agreement on bearing the cost of fighting climate change before a UN summit on global warming next month.