PARIS  After bruising global downturns, the American economy has usually led the world back to growth, but developing countries could be the engine that powers the next recovery.

Despite fears just months ago that they would be among the biggest victims of the financial crisis, emerging giants like China, India and Brazil are set to rebound strongly next year, the Organization for Economic Cooperation and Development predicted Wednesday  as Europe, the United States and Japan lag.

“It’s good to have a locomotive out there pulling the train,” Ángel Gurría, the O.E.C.D.’s secretary general said, referring to China, India and Brazil. “But we can’t put the onus on their shoulders  they help, but they can’t get us out of the hole.”

The divergence between the emerging and the developed countries suggests that the once-popular theory of decoupling  the notion that the emerging markets could be moving independently of the developed economies  may make a comeback.