The International Monetary Fund's (IMF) Chief Economist Oliver Blanchard has warned that the fiscal problems in the U.S. stemming from the 2008 Financial Crisis remains unresolved till today; and said that it will take "at least a decade" for the global economy to recover from the crisis.

In an interview with the Hungarian website, Portfolio online financial journal, Blanchard noted that while all the focus was now on Europe's debt crisis, the U.S. still "has a fiscal problem which it hasn't dealt with yet and that it has to deal with."

It's not yet a lost decade... But it will surely take at least a decade from the beginning of the crisis for the world economy to get back to decent shape," Blanchard said.

Additionally, Blanchard admitted that the crisis on Wall Street had led many to rethink the economic impact of the financial sector, claiming that "there was no research on this issue before," and "it was not as central as it is today."

"We clearly have had to do a lot of new thinking, and there's still a lot of thinking to be done," Blanchard told Portfolio.hu.

"We had assumed that we could ignore much of the details of the financial sector...we felt we did not need to understand exactly who did what on Wall Street. We underestimated the complexity of the system, and the fact that a financial shock could nearly destroy the economy. This has been made very obvious by the crisis," he said.

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On today's eurozone debt crisis, Blanchard advised that that adjustment in the euro zone would require a decrease in prices in the bloc's indebted southern half and a rise in core countries.

"If the ECB wants to maintain two percent inflation for the Euro zone as a whole, this implies, arithmetically, that core countries have to have inflation higher than two percent, periphery countries have to have inflation lower than two percent, until the adjustment has taken place," he said.

Debt reductions were unavoidable but it should be done without stifling growth, Blanchard added, describing the process as walking on a "narrow middle path".

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If you do it too slow, the market thinks you're not serious; if you do it too fast, you kill the economy. For each country you have to find the right path of consolidation," he said.