We could be in store for a financial crisis worse than the one in 2008 and 2009, says Marc Faber, publisher of The Gloom, Boom & Doom Report.

Such a crisis could begin in the second half of the year, he tells CNBC.

One problem is debt. Total credit — including government, corporate and consumer debt — as a percentage of GDP is 30 percent higher in advanced economies than in 2007, Faber explains.

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This isn't exactly blissful news for the economy. "I don't think that is the economy recovering at all. We have in the emerging economies a slowdown, export growth is nonexistent."

Geopolitics aren't helping things either, he adds, citing turmoil in Ukraine and the South China Sea.

So what can central banks do?

"They have something left — that is to throw even more money down the drain," he argues. And that leads to price increases.

"Nobody can deny anywhere in the world that energy prices are substantially higher than they were 10 years ago. Nobody can deny that food prices are up. . . . To throw money at the system will at some point lead to pressure."

Faber believes "stocks in the advanced economies are basically fully priced" and that, given their low yields, government bonds are expensive.

Therefore, he predicts cash might be the most attractive asset for the next six months.

Meanwhile, Federal Reserve Chair Janet Yellen's congressional testimony Wednesday indicated the central bank wouldn't raise interest rates anytime soon, economists said.

"She wants to reiterate that there are still challenges, we're not out of the woods yet, and it's too early to think about starting to remove accommodation," Michelle Meyer, senior economist at Bank of America, tells Bloomberg.

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