The global economic outlook is more uncertain now than at the start of the financial crisis in late 2008, chief executive of Caterpillar, Doug Oberhelman, said on Monday.

The CEO of the world's largest maker of construction equipment also predicted that it could take another five years before Europe's economy begins to see growth again.

"There's never been a more unpredictable set of tea leaves than right now. Even in 2008 and 2009, U.S. housing was already dying and had been for two years. We saw that," Oberhelman is quoted as saying in the Financial Times.

"I don't think the situation is as grave as it was in 2008, but the uncertainty, the storm clouds are around things that none of us know about — like what will happen with the political situation in Europe," he said.

Oberhelman is cited as saying that barring Europe, most big economies looked unlikely to contract, although he said it was not clear whether they would grow significantly.