WASHINGTON (AFP) - The global recovery from recession has begun but a delicate rebalancing of economies is needed to ensure its sustainability, the International Monetary Funds chief economist said Tuesday. The recovery has started. Sustaining it will require delicate rebalancing acts, both within and across countries, Olivier Blanchard said in an IMF article, released in advance of publication Wednesday. Blanchard cautioned that predictable models based on past recoveries from recessions would not apply to the worst global slump in seven decades. The world is not in a run-of-the mill recession. The turnaround will not be simple. The crisis has left deep scars, which will affect both supply and demand for many years to come, he said. The top economist at the 186-nation institution noted that in a typical battle against recession, the central bank lowers interest rates, which results in increased demand and output, and often a decline in the value of the currency boosts exports by making them cheaper. The lower-than-normal growth during the recession gives way to higher-than-normal growth for some time, until the economy has returned to its normal growth path, Blanchard said. The current global recession is far from normal, he said, citing the breakdown in parts of the economic system. In advanced countries, the financial systems are partly dysfunctional, and will take a long time to find their new shape, he wrote in the article, titled Sustaining a Global Recovery. Emerging market countries may not see dwindled capital inflows return to pre-crisis levels for a few years. The United States, the epicenter of the crisis, is central to any world recovery, he said. Blanchard said two rebalancing acts will have to come into play to sustain the global recovery: a switch from public to private spending and the rebalancing of international trade flows. The latter would require a shift from domestic to foreign demand in the United States and a reverse shift from foreign to domestic demand in the rest of the world, particularly in Asia, he said. Pointing to a decline in American household consumption which represents 70 percent of total US demand and a rise in the personal saving rate that is expected to persist for some time, Blanchard estimated a 3.0 percentage point drop in the ratio of consumption to US gross domestic product, a broad measure of economic output. With the 3.0 percent drop unlikely to be made up by increased investment and the eventual phase-out of the massive fiscal stimulus, US net exports must increase for the US recovery to occur, he said. The key to the rebalancing act will be in increased foreign demand for US goods, particularly in countries with large current account surpluses, notably in China and other Asian countries. From the point of view of the United States, a decrease in Chinas current account surplus would help increase demand, and sustain the US recovery. That would result in more US imports, which would help sustain world recovery, he said. China may be willing to pursue that because it may well be in its own interest, said the economist, but other emerging market Asian countries that run large current account surpluses have weaker incentives than China to boost internal demand. The end result of the global crisis: possibly a permanently lower potential output, he said. Blanchard said the IMFs upcoming latest edition World Economic Outlook will cover 88 banking crises over the past four decades in a wide range of countries. While there is large variation across countries, the conclusion is that, on average, output does not go back to its old trend path, but remains permanently below it, he said.