The United States may emerge from recession in a technical sense as early as this summer, though a likely worsening in labor conditions means a "depressed economy" could last as long as five more years, Nobel Prize-winning economist Paul Krugman said Tuesday. "I think it's quite possible that industrial production in the United States and perhaps in the world as a whole will bottom out sometime in the next few months, that GDP growth in the United States will be positive in the second half of the year and maybe a little bit later than that in Europe," Krugman told participants at a global financial conference. Krugman said that he would not be surprised if the US recession, which began in December 2007, ended in August or September this year. Deteriorating labor markets, however, were likely to continue on into 2011, meaning "the period of a depressed economy" could last until 2013 or 2014. Krugman, who teaches at Princeton University, won the Nobel Memorial Prize in Economic Sciences last year for his analysis of how economies of scale can affect international trade patterns. He also writes columns for The New York Times.