Stocks are likely to continue their aggressive decline and shed another 20 percent in value as the world economy weakens, noted economist Nouriel Roubini told CNBC.
As the market slides into correction territory, Roubini said weakness in euro zone countries and a slowdown in the US and other developed countries will make things even more difficult for investors in the months ahead.
"There are some parts of the global economy that are now at the risk of a double-dip recession," said Roubini, head of Roubini Global Economics. "From here on I see things getting worse."
Prices in both stocks and commodities are likely to take a hit, and investors may only be safe in cash and other safe havens. Roubini said investors also can use options to hedge against future market risk that he said is sure to come as conditions weaken in the US, Japan, China and through much of Europe.
That will lave little room for growth both in economic measures and in most investment classes, Roubini said.
"There is that risk because the problems on the macro level are first in the euro zone. Then in China there is evidence of economic slowdown...Japan is in trouble and US economic growth is going to slow down," he said. "There is also regulatory risk because we don't know how financial reform is going to occur."
Investors then should focus on buying debt from countries that are solid economically.
"Apart from cash I would invest in short-term government bonds of countries that don't have a serious debt problem, countries like Germany and maybe Canada, a few other advanced economies that from a fiscal point of view are sounder than the weaker economies," he said.
As for Europe, he called fixing the debt problems in Greece and other troubled nations "mission impossible" and said tough decisions will need to be made.
"What needs to be done is clear. We need to raise taxes and cut spending. Otherwise we're going to get a fiscal train wreck," he said. "It's going to take years of sacrifices."
In 2006 Roubini predicted the impending housing bust and ensuing financial crisis. His predictions and comments are widely followed in financial circles.