Oct. 29 (Bloomberg) -- The global financial crisis hasn’t ended, said Harvard University professors Kenneth Rogoff and Niall Ferguson, who challenged assertions made by Group of 20 leaders at their meeting in Pittsburgh last month.

“The G-20 is right that it’s over for all the banks they guaranteed,” Rogoff, 56, a former chief economist at the International Monetary Fund, said yesterday in an interview with Bloomberg Radio. Even so, as a consequence of bailouts and stimulus measures, “the financial crisis may eventually morph into a government-debt crisis.”

G-20 leaders last month adopted a framework for more durable economic growth as they sought to prevent a replay of the worst crisis since the Great Depression. They pledged to strengthen international financial regulations, rein in banker pay and keep stimulus measures in place until growth takes hold.

“Crises last longer than most people think,” said Ferguson, author of The Ascent of Money: A Financial History of the World.

“Most crises, major financial crises worthy of the name depression or indeed recession, last significantly longer than a day and they can be measured more in the thousands of days. I think it would be very unwise to say it’s over.”

Ferguson, 45, added that “within our lifetimes the United States will cease to be the world’s largest economy.”

China’s economy, the world’s third largest, expanded at the fastest pace in a year in the third quarter as stimulus spending and record lending growth helped the nation lead the world out of recession. Gross domestic product rose 8.9 percent from a year earlier, the statistics bureau said on Oct. 22.

$1.4 Trillion

The U.S. government ended its 2009 fiscal year with a deficit of $1.4 trillion, the Congressional Budget Office reported earlier this month.

The deficit for the year ended Sept. 30 amounted to 9.9 percent of the world’s biggest economy, or triple the size of the shortfall for 2008. The spending increases and tax cuts included in the economic stimulus package approved in February added almost $200 billion to the 2009 deficit, the CBO said.

To contact the reporters on this story: Vivien Lou Chen in San Francisco at vchen1@bloomberg.net; Thomas R. Keene in New York at tkeene@bloomberg.net

Last Updated: October 29, 2009 00:01 EDT