经济学人下载:2021美国的发展牵一发而动全身(1)

Radiant energy 

辐射能

If America's economy runs hot, what happens to the rest of the world? 

如果美国经济过热，世界其他地区会发生什么？

When america sneezes, the rest of the world catches a cold. But what happens when it runs a fever? After a trying 2020 in which GDP fell by 3.5%, America is poised to enjoy a robust rebound in 2021 simply by returning to something like normal as vaccination proceeds. Yet it might manage more than just that. If President Joe Biden's covid-19 relief bill is enacted, total stimulus this year may exceed $2.5trn. That could easily push output above what the Congressional Budget Office estimates to be its "potential" level: that is, the amount the economy can produce without an increase in inflationary pressure. This possibility has some American economists on the lookout for signs of accelerating growth in prices and wages. America does not operate in a vacuum, however; should overheating occur, its effects will not be con- fined within its borders. Depending on how the recovery plays out, a hot American economy could be a boon for the rest of the world—or yet another source of concern. 

当美国打喷嚏时，世界其他地方就会感冒。那么它感冒时会发生什么呢？2020年美国经历了艰难的一年，GDP下降了3.5%。而随着疫苗接种的进行，一切回归正常，那么美国有望在2021年实现强劲反弹，而且可能会反超。如果拜登总统的新冠救助法案获得通过，今年的刺激总额可能会超过2.5万亿美元。这很容易使产出超出国会预算办公室估计的“潜在”水平：即在通胀压力不增加的情况下经济能够产出的总量。这种可能性使得一些美国经济学家在寻找物价和工资加速增长的迹象。然而，美国并不是在“真空”中运作，如果出现过热，其影响将不会局限于国内。美国经济的繁荣对世界其他国家来说可能是福音，也可能是另一个担忧的来源，这取决于经济复苏的结果。

In a closed economy that does not trade with the rest of the world, too little spending leads to job losses and downward pressure on prices, whereas too much should push up employment and, eventually, prices. In an open economy, however, some of the effects of the shifts in demand spill over to the rest of the world. A sharp drop in spending, for instance, may be associated with plunging demand for imports, in which case some of the pain of a slump is exported abroad. During the global financial crisis of 2007-09, troubles in financial markets wreaked havoc all over the world, but even countries relatively insulated from those woes felt a chill thanks to trade links with America and Europe. According to one estimate, about a quarter of the drop in American demand and a fifth of the fall in European demand was borne by other economies, and transmitted through trade. 

在一个不与世界其他地区进行贸易的封闭经济体中，支出过少会导致失业和价格下跌压力，而支出过多则会推高就业率，最终推高价格。然而，在一个开放的经济体中，需求变化的一些影响会溢出到世界其他地区。例如，消费的急剧下降可能与进口需求的急剧下降有关，在这种情况下，经济衰退带来的一些痛苦会出口到国外。在2007年至2009年的全球金融危机期间，金融市场的问题在全球范围内造成了严重破坏，但由于美国和欧洲的贸易联系，即使是那些与这些灾难相对隔绝的国家也感受到了寒意。据估计，美国需求下降的四分之一和欧洲需求下降的五分之一是由其他经济体承担的，并通过贸易传导。

A boost to demand ought to work in a similar way, but in the other direction. As Americans spend more, some of it leaks abroad: through purchases of foreign goods, for example, or spending on services—including tourism, which should begin to rebound as pandemic restrictions are lifted. An analysis of fiscalpolicy spillovers published by the IMF in 2017 found that an American stimulus consisting mostly of spending (as opposed to tax cuts) and worth 1% of GDP raises the output of the average country by 0.33% in the first year. Countries with closer trade ties experience bigger effects; the fillip to Canada's economy is estimated to be almost three times the average, for example. If the combination of reopening and stimulus invigorates the American consumer, the effects could quickly be felt all over the world. 

刺激需求应该以类似的方式发挥作用，但方向相反。随着美国人消费的增加，其中一部分消费会流向国外：例如，通过购买外国商品，或者在服务方面的支出——包括旅游——随着新冠限制的解除，旅游业应该会开始反弹。国际货币基金组织在2017年发布的一份关于财政政策溢出效应的分析报告发现，美国的刺激计划主要由支出(而不是减税)组成，占GDP的1%，第一年能使国家的平均产出提高0.33%。贸易联系越紧密的国家影响就越大。例如，据估计，加拿大经济的刺激几乎是平均水平的三倍。如果重新开放和刺激措施的结合能刺激美国消费者，那么其影响很快就会波及到全世界。