If policymakers in the eurozone and Japan hoped to engineer a weaker currency by their aggressive expansion of monetary policy, they must be watching the latest moves in currency markets with dismay. Despite fresh rounds of quantitative easing and radical experiments with negative interest rates — usually associated with a weaker exchange rate — the euro and yen have rallied. Threats of official intervention from Tokyo did nothing to prevent the yen climbing last week to a 17-month high against the dollar.

如果欧元区和日本的政策制定者希望通过货币政策的积极扩张使得汇率下跌，他们肯定正在沮丧地看着最近外汇市场的动向。尽管推出了数轮量化宽松并祭出了负利率的激进试验——通常会导致汇率下跌的举措——但是欧元和日元汇率均出现上涨。日本官方干预市场的威胁未能阻止日元兑美元汇率近日攀升至17个月高点。

Interpreting the vagaries of foreign exchange markets is a risky business. One popular conclusion, though, has been that these moves betray the helplessness of central banks, for whom a weak currency would be an invaluable tool. Investors think the European Central Bank and Bank of Japan are nearing the limits of monetary policy and no longer believe they will be able to revive growth and fight off deflation.

解读外汇市场的异常波动是一件冒险的事。不过，一条广为接受的结论是，这些举动暴露出央行的无能为力，对于它们来说，疲软的本币汇率将是一项非常宝贵的工具。投资者认为欧洲央行(ECB)和日本央行(BoJ)对货币政策的运用即将达到极限，他们不再认为两家央行有能力恢复经济增长并对抗通胀。

There is some truth in these fears. The yen’s current level is hardly a ringing endorsement of Abenomics. Nonetheless, the perverse behaviour of foreign exchange markets does not necessarily reflect despair over the state of the global economy. Yen and euro strength is at least in part a consequence of the recent change in stance by the US Federal Reserve, which has signalled that it is in no hurry to proceed with a second rise in interest rates.

这些担忧有一定道理。日元目前的汇率水平远算不上是对安倍经济学(Abenomics)的有力背书。尽管如此，外汇市场的异常表现也未必反映出市场对全球经济状况感到绝望。日元和欧元走强至少部分是因为近期美联储(Fed)的立场转变，该央行释放信号称其不急于接着进行第二次加息。

This has triggered weakness in the dollar, now back at last October’s level against a basket of major currencies. This makes the job of the ECB and BoJ harder but will be a great relief to policymakers in many emerging markets. It helps oil exporters that were struggling to keep currency pegs in place — especially as a weaker US currency tends to support commodity prices. It takes the pressure off countries that built up huge volumes of dollar-denominated debt thanks to the excesses encouraged by quantitative easing.

这引发了美元走低，如今美元对一篮子主要货币的汇率回到了去年10月的水平。这使得欧洲央行和日本央行的工作更难收到成效，但也使得很多新兴市场的政策制定者松了一大口气。美元走低有利于此前难以维系汇率挂钩的石油出口国——尤其是因为美元走低往往可以支撑大宗商品价格。美元走低缓解了美元债务庞大的国家身上的压力，而导致这些国家积累起庞大美元计价债务的原因，正是当初量化宽松所催生的无节制行为。

Above all, it has already helped China avert a sharp devaluation in the renminbi — addressing one of the biggest fears that fuelled the turbulence in global markets at the start of the year. The Chinese currency has bounced back from January’s lows, with data from March showing the first rise in the country’s foreign exchange reserves in five months.

最重要的是，美元走低已然帮助中国避免了人民币急剧贬值——解除了今年年初造成全球市场波动的最大担忧之一。人民币汇率已经从1月的低点有所反弹，3月数据表明中国外汇储备5个月来首次回升。

One theory among investors has been that policymakers reached a tacit understanding on the advantages of a weaker dollar at February’s G20 meeting — an echo of the 1985 Plaza accord. This seems improbable, given repeated pledges to avoid any targeting of exchange rates. The Fed’s internal deliberations, however, show a growing appreciation of the risks that global financial turbulence and a global slowdown pose to the US recovery.

投资者中间流传的一种说法是，在2月的二十国集团(G20)会议上，各国的政策制定者就美元走低的好处达成了默契——1985年广场协议(‎Plaza Accord)的情景再次上演。考虑到各国再三承诺要避免任何瞄准汇率的行为，这种情况似乎极不可能。然而，美联储内部讨论表明，该央行日益充分地认识到了全球金融动荡和全球经济放缓对美国经济复苏构成的风险。

Moreover, central banks in advanced economies need to give increasing weight to the effects of their actions on emerging economies. The International Monetary Fund warned this week that “spillovers” from China to global financial markets would grow considerably over the next few years.

此外，各发达经济体的央行需要日益重视其政策举动对新兴经济体的影响。国际货币基金组织(IMF)上周警告称，未来数年，中国对全球金融市场的“溢出效应”将大幅增加。

The Federal Reserve cannot ignore the reality that its actions will have global consequences. The possibility of a shock Chinese devaluation or a debt crisis that might bring down governments in emerging markets is a more alarming prospect than the ever-present risks of sluggish growth in developed economies.

美联储不能忽视其举动将对全球市场造成的影响。人民币可能急剧贬值或者可能发生一场可能让新兴市场多个政府下台的债务危机的前景，比始终存在的发达经济体增长滞缓的风险更令人担忧。

At present, a policy stance that helps moderate strength in the dollar is in the best interests of the US and of the global economy. Insofar as any conclusion can be drawn from unpredictable short term moves in exchange rates, it is that the eurozone and Japan are suffering collateral damage.

目前，有助于缓和美元走强的政策立场最符合美国乃至全球经济的利益。如果可以从变化莫测的短期汇率波动得出任何结论的话，那就是欧元区和日本正在承受连带损害。