????中國一位頂尖的經(jīng)濟(jì)學(xué)家發(fā)出警告，全球已陷入“美元陷阱”——美國的貿(mào)易伙伴國既缺乏可替代美元的貨幣選擇,，也無法阻止美聯(lián)儲（Federal Reserve）印發(fā)更多美元,。

????這意味著大量持有美元資產(chǎn)的國家——如中國，該國大約3萬億美元的外匯儲備中大部分是美元資產(chǎn)——只能坐視資產(chǎn)貶值,。也不能輕易地進(jìn)行貨幣多元化,，因為這可能加速美元資產(chǎn)的縮水。

????現(xiàn)行國際貨幣體系“既缺乏穩(wěn)定性,，也缺乏公平性”,，中國國際經(jīng)濟(jì)交流中心的經(jīng)濟(jì)學(xué)家徐洪才寫道。

????徐洪才的這番言論見報,，時間正是二十國集團(tuán)（G-20）財長會議于3月31日在南京召開前,。二十國集團(tuán)財長將討論如何取代當(dāng)前以美元為中心的國際貨幣體系——這個問題多年來一直困擾著經(jīng)濟(jì)學(xué)家和政策制定者們，隨著中國的崛起,，這個問題變得更為緊迫,。

????此次會議召開之際，美元指數(shù)正徘徊于近期低點附近,，原因是美國經(jīng)濟(jì)困頓以及美國聯(lián)邦儲備委員會的擴(kuò)張性貨幣政策,。雖然日本遭受了大災(zāi)，但過去一年美元/日元走低,；即便是歐洲可能迎來新一輪耗資巨大,、存在政治爭議的援助計劃，美元/歐元也未能走高,。

????徐洪才在文章中建議,，應(yīng)建立一個由國際貨幣基金組織（International Monetary Fund）等類似機(jī)構(gòu)監(jiān)管的多儲備貨幣體系。他指出,，（當(dāng)一種儲備貨幣貶值時,，）國際貨幣基金組織可以發(fā)出警告，迫使相關(guān)國家采取干預(yù)措施,，穩(wěn)定幣值,。路透社（Reuters）認(rèn)為，這一提案不太可能得到西方人的認(rèn)可,，西方人更贊成已實行幾十年的自由浮動匯率體系,。

????當(dāng)然，要解決這個已延續(xù)幾十年的問題絕非易事。但《華爾街日報》(Wall Street Journal)的一篇報道稱,，此次會議自由交換意見的氛圍可能不如以往,。中國官員對于美元貶值和嚴(yán)格管制人民幣匯率的話題非常敏感，已敦促參與各方不要談?wù)撎窖髢砂稛嶙h的匯率問題,。

????雖然這似乎是個好辦法,，但沉默并不能讓這個問題自動消失。

????A top Chinese economist warned that the world has fallen into a "dollar trap," as U.S. trading partners lack an alternative to the greenback and can't prevent the Federal Reserve from printing more money.

????The arrangement means big holders of dollars – such as China, which holds some $3 trillion of foreign exchange reserves, mostly in dollars – must sit idly by and watch as the value of their holdings erode. They can't lightly diversify out of dollars at the risk of accelerating the erosion.

????The setup "lacks both stability and fairness," wrote Xu Hongcai, an economist at the China Center for International Economic Exchanges.

????He made the remarks in a paper published ahead of Thursday's meeting of G-20 finance ministers in Nanjing. They will discuss what might replace the current dollar-centric system – a subject that has vexed economists and policymakers for years and has grown more pressing with the rise of China.

????The meeting comes at a time when the dollar index is near its recent lows, thanks to the stumbles of the U.S. economy and the expansive monetary policy of the Fed. The dollar is down over the past year against the yen in spite of a massive disaster in Japan, and has failed to appreciate against the euro even as the Continent stumbles toward another spring of costly, politically divisive bailouts.

????Xu, for his part, suggests moving toward a system of multiple reserve currencies overseen in part by the likes of the International Monetary Fund. He says the IMF could issue alerts that would prompt countries to intervene to hold the value of their currencies steady. Reuters notes that the proposal isn't likely to pass muster with Westerners who favor the free-floating system that has been in place for decades.

????There is no easy answer to a problem that has built up over decades, of course. But a report in the Wall Street Journal says the session promises to be even less of a free-flowing exchange of ideas than usual. Chinese officials are so sensitive on the subject of the weakening dollar and their tight control of their own currency, the yuan, that they have urged participants not to discuss the exchange rate issue that has been so heatedly debated on both sides of the Pacific.

????But as appealing as that may sound, giving this problem the silent treatment is not going to make it go away.