"This is not a turning point," said Kevin Norrish, a London-based managing director at Barclays Capital, whose commodities research team is ranked by Bloomberg in the top three for copper and gold. "We'd expect to see a pretty good recovery from these levels before too long."

The S&P GSCI climbed 2.1% by 10:49 a.m. in London as silver futures rose 4% and crude oil in New York added 3%.

Brent crude should rebound about 2% to $115 a barrel in coming weeks because violence in northern Africa and the Middle East continues, said Christin Tuxen, an analyst at Danske Bank A/S in Copenhagen and the most-accurate oil forecaster tracked by Bloomberg over eight quarters. The fighting already curbed supply from Libya and increased concern that it may spread to regional producers including Saudi Arabia.

JPMorgan Chase & Co. raised its oil-price forecasts for this year and next on May 6 because it expects production to fall short of demand. Brent crude will average $120 in 2011 and 2012, from previous estimates of $110 and $114, the bank said. Oil prices should match or top their recent highs by next year, Goldman said in a note to clients on the same day.

Global Recession

The bears say that even if the economy grows, speculation is so excessive that prices no longer reflect supply and demand. The S&P GSCI Index still is 34% higher than a year ago and more than twice where it was in February 2009, when economies were recovering from the global recession.

Commodities are at the start of a bear market that may last as long as five to 10 years, said Michael Aronstein, the president of Marketfield Asset Management in New York who correctly predicted the 2008 slump that drove the benchmark index down 66% in seven months.

The scale of investment means "supply and demand is almost meaningless," Aronstein said in an interview May 6. "It's almost like the last days of the tech bubble."

Oil, which lost 15% last week in New York and 13% in London, became "detached from fundamentals," said Oswald Clint, London-based head oil analyst at Sanford C. Bernstein, the joint-most-accurate oil forecaster tracked by Bloomberg in 2010. Brent could drop below $100 a barrel, about 11% lower than now, he said.

Commodity Funds