Business activity in the United States unexpectedly accelerated in November as orders climbed, signaling the economic recovery will carry through into 2010. The Institute for Supply Management-Chicago Inc. said today its barometer rose to 56.1, the highest level since August 2008, from 54.2 the prior month. Readings above 50 signal expansion. Rising sales, spurred in part by government incentives, and growing demand from abroad have led to a drawdown in inventories that will boost production and sustain the recovery. Mounting job losses raise the risk spending will retrench, one reason why Federal Reserve policymakers have pledged to keep borrowing costs low “for an extended period.” “There is definitely room for production to be coming back,” said David Semmens, an economist at Standard Chartered Bank in New York, who forecast the index would rise. “There will be some export-led growth.”