George Soros, the billionaire financier, unveiled a plan yesterday to lend poor countries $100bn to deal with the threat of climate change. The money would come from the International Monetary Fund, from financial instruments known as special drawing rights. These SDRs, used to create liquidity, are a type of basket "currency" used as an accounting unit by the IMF, and held by countries as part of their reserves. Speaking at the UN climate conference in Copenhagen, Mr Soros argued that the reserves were unnecessary and should be lent to developing countries through a "green fund". "It is possible to substantially increase the amount available to fight global warming in the developing world by using the existing allocations of SDRs," he said. "All that is lacking is the political will . . . Yet it could make the difference between success and failure at Copenhagen." No decision on Mr Soros's idea is likely at Copenhagen but it could receive more attention in the coming months as rich countries struggle to agree how to finance pledges they make at the conference. In the meantime, rich and poor countries have traded blows over financing. Poor countries are demanding at least $100bn (