By Yu Yongding

BEIJING ― Before the global financial crisis hit, critics of China's economic imbalances ― its twin fiscal and trade surpluses ― mainly concentrated on the misallocation of resources that occurs when poor countries borrow from rich countries at high interest rates and lend the money to them at low interest rates.

The great irony of the financial crisis is that the situation has become worse, not better.

China's foreign-exchange reserves, indeed, are facing a triple whammy: a decline in the U.S. dollar's purchasing power, a fall in the prices of U.S. government securities, and possible inflation in the longer run.

The bulk of China's $2.3 trillion in foreign reserves are held not for the purpose of protection against negative external shocks, but as savings in the form of U.S. Treasury notes. China thus needs to preserve the value of its savings.

But there is no question whatsoever that the U.S. dollar will go south in the long run ― a depreciation that started in April 2002 and, after a short interval, resumed in March 2009. Unless the U.S. economy improves its trade balance, the dollar will fall.

But the U.S. cannot improve its trade balance unless the dollar falls. Measured by the dollar index, therefore, capital losses on China's foreign exchange reserves are inevitable.

Due to the huge U.S. budget deficit, the supply of American government bonds will increase astronomically in the years ahead. But there is no guarantee that demand for these Treasury notes among foreign investors ― including foreign governments ― will be sufficient.

So it is very likely that when the global economy has returned to a sort of normality and safe-haven demand has declined, the prices of U.S. government securities will fall and their yields will rise.

As a result, China's dollar-denominated foreign-exchange reserves, which account for the largest share of all the foreign holdings of U.S. government securities, will suffer interest-rate losses.

Moreover, the U.S. Federal Reserve is targeting a 4 percent annual inflation rate. This alone means that under normal circumstances the purchasing power of China's foreign-exchange reserves will automatically depreciate by 4 percent each year.

Due to the extremely expansive U.S. monetary policy that has been in place since the sub-prime crisis began two years ago, the real value of China's foreign-exchange reserves has already been eroded, with or without inflation.

China is like the shareholders of a company that has increased the supply of its shares in a stealthy way: the share price may not have fallen yet, but it will.

Unless the Fed successfully implements an exit strategy from monetary expansion, which is doubtful, China will not be able to recover its losses.

A less likely but more damaging scenario is that all the money dropped on the economy by U.S. Federal Reserve Chairman Ben Bernanke will eventually stoke a bout of serious inflation.

If this nightmare comes true, China's packed savings in the form of U.S. government securities (which now amounts to some $900 million in Treasury bills alone) will simply go down the drain.

Despite China's limited room for maneuver with regard to its stocks of foreign-exchange reserves, it should never give up its efforts to safeguard the value of its hard-earned wealth, which has been entrusted to the good will and supposedly responsible hands of the U.S. government.

As the stronger and more experienced party, the U.S. can help to allay China's fears about the safety of its national savings.

For example, the U.S. government should offer more financial instruments like Treasury Inflation-Protected Securities (TIPS), thereby allowing China to convert some of its holdings of U.S. government securities into similar but safer assets.

Furthermore, China should be allowed to convert part of its foreign-exchange reserves into assets denominated in the International Monetary Fund's special drawing rights (SDRs).

Of course, China should not rule out the possibility of adjusting the composition of its foreign-exchange reserves to mimic the composition of the SDR.

Finally, if the U.S. government cannot safeguard the value its securities, it should compensate China in one way or another.

Only then can China and the world be certain that America's irresponsible attitude ― ``the dollar is our currency, but your problem" ― has become a thing of the past.

Yu Yongding, currently president of China Society of World Economics, is a former member of the monetary policy committee of the People's Bank of China, and a former director of the Chinese Academy of Sciences Institute of World Economics and Politics. For more stories, visit Project Syndicate (www.project-syndicate.org).