When will the recession end?

From the New York Times, a series of answers from eleven economists and business people on when they think the recession will end. A sampling:

A. Michael Spence:

THE short answer is not soon.

The recession is global: exports, production and consumption are in high-speed descent. The headwinds are powerful because of excessive leverage, damaged balance sheets and the resulting tight credit.
...
These factors have led to, first, reduced consumption and then declining investment and employment. This has lowered sales, profits, credit quality and, completing the loop, asset values. This interacting spiral is what makes this recession exceptional.

Governments and central banks are the only major sources of credit, liquidity and incremental demand — private capital and sovereign wealth funds, having experienced losses, are largely sidelined. If governments are quick and clear in their intentions and intervene in a coordinated way in both the real economy and the financial sector, we will probably have an unusually long and deep global recession through 2010. If they don’t, it is likely to be worse than that.

A. Michael Spence is an emeritus professor of management at Stanford who won the Nobel prize in economics in 2001.

Niall Ferguson:

THIS recession, which began in December 2007, has already lasted longer than the average postwar recession. If it turns out to be as bad as the most protracted of the postwar downturns, we will touch bottom next month.

But my strong suspicion is that we are now in something more like a Great Recession. It won’t produce as steep a fall in American output as the Depression did, but it may prove to be as prolonged.

The depression that began in August 1929 did not hit its nadir until 43 months later. The one that started in October 1873 was shallower but lasted 65 months. If the economy were to keep shrinking for that long, we wouldn’t start coming out of this until after May 2013. ...

Niall Ferguson is a professor at Harvard and the author of “The Ascent of Money: A Financial History of the World.”

Alan Blinder:

HERE’S the hard truth: Nobody knows when this recession will end. Economic forecasting is a dark art, and predicting when recessions begin and end is its weakest link. That said, my best guess is that growth will return in the fourth quarter of this year. Why?

First, recessions don’t last forever. If the economy continues to slide through the third quarter, as I anticipate it will, this will be the longest American recession since World War II. Housing must hit bottom at some point. For several years now, declining expenditures on homebuilding have subtracted roughly a percentage point from gross domestic product growth. The change from minus 1 percent to (at least) zero will add a full point to growth. Auto sales are also not likely to keep falling at recent rates. Second, Washington’s large economic stimulus should add more than 5 percent to real gross domestic product over two years. ...

Alan S. Blinder is a professor of economics and public affairs at Princeton and a former vice chairman of the Federal Reserve.

Read the whole set of responses here. Basically, wide disagreement exists among the "experts". Short answer: no one knows. Throw in another successful terrorist attack, mass casualty incident, or the government doing something (ok, something else) really stupid like trying to disarm the populace, and the outlook gets even more uncertain.