The current strength of the dollar is temporary and the US currency risks a hard landing in 2009, according to a team of United Nations economists who foresaw a year ago that a US downturn would bring the global economy to a near standstill.

In their annual report on the world economy published on Monday, the economists said the dollar’s sharp rebound this autumn had been driven mainly by a flight to the safety of the international reserve currency as the financial crisis spread beyond the US.