英国《金融时报》全球经济未来辉煌不再

 

http://www.ft.com/intl/cms/s/2/b345d172-e1cd-11e4-bb7f-00144feab7de.html

 

An economic future that may never brighten

Martin Wolf

 

全球经济未来辉煌不再

英国《金融时报》首席经济评论员马丁·沃尔夫

 

The decline in potential growth leads to debate about the savings glut and secular stagnation

 

It seems at first to be a puzzling scenario, and you might wonder whether it is possible at all: output can be at potential but still not be sustainable. Yet a chapter of the International Monetary Fund’s latest World Economic Outlook illuminates just this scenario. We may even be living in it.

 

乍看之下，这似乎是个令人费解的情景，你甚至可能怀疑到底有没有可能出现这种情景：产出既是潜在的，却也是不可持续的。然而，国际货币基金组织(IMF)的最新一期《世界经济展望》(World Economic Outlook)里，就有一章阐述了这种情景。我们甚至可能已经身处其中。

 

Output is “at potential” when it does not generate inflationary or deflationary pressure. Sustainability — and I am referring here to financial sustainability, not the environmental kind — is something else entirely. Output is financially sustainable when spending patterns and the distribution of income are such that the fruit of economic activity can be absorbed without creating dangerous imbalances in the financial system. It is unsustainable if generating enough demand to absorb the output of the economy requires too much borrowing, real rates of interest rates that are far below zero, or both.

 

当产出不会产生通胀或者通缩的压力，它就是“潜在的”。可持续性——这里我指的是金融方面的可持续性，而不是环境方面的——则完全是另一回事。当支出模式和收入分配使经济活动的成果能被吸收，而不引起金融系统的危险失衡，产出在金融方面就是可持续的。如果产生足够需求来吸收经济中的产出需要过多借贷，或远低于零的实际利率，或者二者兼有，产出就是不可持续的。

 

To see how that predicament might arise, start by imagining an economy that is balanced in the sense that the amount of money which households and businesses wish to save is exactly the same as the amount they wished to spend on physical investments. So far, so good. But suppose growth of potential output then fell sharply. The level of desired investment would also fall, because the needed capital stock would be smaller. But the amount that people wished to save might not fall, or not by as much; in fact, if people expect to be poorer in future, they might even wish to save more. If so, real interest rates might need to decline sharply, to restore balance between investment and savings.

 

要理解上述令人费解的情景如何可能产生，可以想象一个平衡的经济体，其中家庭和企业希望储蓄的钱，与希望进行实体投资的钱在金额上完全相等。到目前为止，一切都很好。但设想一下潜在产出增速开始大幅下滑的情况。投资意愿会减弱，因为所需的资本存量变小了。但人们想要储蓄的金额可能不会下降，或者至少不会下降那么多；事实上，如果人们预期自己在未来会变得更加贫穷，他们甚至会希望储蓄更多。如果是这样，实际利率可能需要大幅下降，才能恢复投资和储蓄之间的平衡。

 

Such a decline in real interest rates might also trigger a rise in the price of long-term assets and an associated surge in credit. These effects would offer a temporary remedy to the faltering demand. But if the credit boom later collapsed, leaving borrowers struggling to refinance debt, demand would then operate under a double burden. The medium-term consequences of excess debt and a risk-averse financial sector would aggravate the longer-term consequences of the weaker potential growth.

 

实际利率的这种下降还可能引发长期资产价格的上涨，以及信贷的相应激增。这些影响会对需求减弱起到临时的补救作用。但如果之后信贷繁荣崩溃，迫使借款人艰难地对债务进行再融资，那时需求就不得不面临双重负担。过度负债和规避风险的金融业产生的中期影响，会加剧潜在增长减弱引发的长期影响。

 

The WEO illuminates one important aspect of such a story. Potential output, it argues, is indeed growing more slowly than before. In the advanced countries, the decline began in the early 2000s; in emerging economies, after 2009. (See charts.)

 

《世界经济展望》阐明了这个过程的一个重要方面。该报告提出，潜在产出事实上比以前增长得更慢了。在发达国家，这一下行趋势在21世纪初就开始了，而在新兴国家，这一趋势始于2009年以后。（见图）

 

Before the crisis, the principal cause of the slowdown in the advanced economies was a decline in the growth of “total factor productivity” — a measure of the output generated by a given amount of capital and labour. One explanation was the waning of the beneficial economic impact of the internet. Another was the decline in the rate of improvement in human skills. After the crisis, potential growth fell still further, partly because of the collapse in investment. The ageing of the population has also been important.

 

在危机前，发达国家潜在产出增长放缓的主要原因是“全要素生产率”增长的下滑。全要素生产率衡量的是给定数量的资本和劳动力产生的产出。一种解释是，互联网带来的有益于经济的影响逐渐减退。另一种解释是人类技能提升速度下降。在危机之后，潜在增长率进一步下滑，部分原因是投资的大幅减少。人口的老龄化也是一个重要因素。

 

In emerging economies, too, demographic factors have been at work: the decline in the growth of the working-age population is particularly dramatic in China. Capital growth is also falling after a huge investment boom in the 2000s, again particularly in China. Growth of total factor productivity might also fall in the longer run, as the rate of catch-up on advanced economies slows.

 

人口因素对新兴经济体也有影响，劳动年龄人口增长率下降在中国尤为明显。在经历了2000年代巨大的投资热潮后，投资增长率也在下降，而且又以中国尤为明显。长远来看，随着新兴经济体追赶发达经济体的速度减缓，全要素生产率的增长可能也会放缓。

 

This decline in potential growth leads directly to the debate about the savings glut and secular stagnation. Two important distinctions emerge: between the local and the global, and between the temporary and the permanent. The global slowdown in potential growth casts light on both.

 

这种潜在增长率的下降直接引发了关于储蓄过剩和长期停滞的争论。两个重要的分歧就此产生：本地还是全球，暂时还是永久。全球经济潜在增长放缓，对这两点分歧都有启示。

 

Ben Bernanke, former chairman of the US Federal Reserve, rightly argues that ultra-low real interest rates should not be determined purely by local conditions. In an economy where desired savings exceed desired investment, it should be able to export excess savings via a current account surplus. That is what Germany has been doing.

 

前美联储(Fed)主席本•伯南克(Ben Bernanke)正确地指出，超低实际利率不应单纯由本地条件决定。当一个经济体的储蓄意愿超过了投资意愿，就应该能够通过经常账户盈余出口过度储蓄。德国就是这么做的。

 

Yet difficulties arise. First, as the Nobel laureate Paul Krugman notes, the real exchange rate may just not fall far enough. If so, the economy might suffer from permanent stagnation instead. Second, the rest of the world might be unable to run offsetting deficits sustainably. This was what happened in the run-up to 2007. The deficits run by the US, Spain and a number of other countries as a counterpart to the surpluses of China, the oil exporters, Germany and other high-income economies turned out to be frighteningly unsustainable.

 

然而问题产生了。首先，如诺贝尔经济学奖得主保罗•克鲁格曼(Paul Krugman)指出，实际汇率可能不会跌到位。如果是这样，该经济体可能会陷入永久性停滞。其次，全球其他国家可能无法维持与该经济体的经常账户盈余相抵消的赤字。2007年金融危机前期就发生过这一幕。当时中国、各石油出口国、德国和其他高收入经济体处于盈余，与之相对应，美国、西班牙及其他许多国家处于赤字，结果赤字惊人地不可持续。

 

Now turn to the no less fundamental distinction between temporary and permanent excesses of desired savings over investment. The main difference between Mr Bernanke and Lawrence Summers, former US Treasury secretary, is over precisely this.

 

接着再来说另一个同样根本性的分歧——储蓄意愿大于投资意愿是暂时的还是永久的。伯南克与美国前财长劳伦斯•萨默斯(Lawrence Summers)的主要分歧正在于此。

 

Mr Bernanke suggests that the conditions generating ultra-low real interest rates are temporary. Obvious examples are the now-vanished surpluses of oil exporters. Again, the pre-crisis current account surpluses of China have largely disappeared. The crisis-induced slump should also be temporary.

 

伯南克认为，产生超低实际利率的条件是暂时的。明显的例子是石油出口国的盈余现在已消失。而且中国在金融危机前的经常账户盈余也已基本消失。金融危机引发的不景气应该也是暂时的。

 

Against this, Mr Summers suggests that at least some of the conditions predated the crisis and are likely to be longer lasting. Among these was the weakness of private-sector investment in high-income economies.

 

对此表示反对的萨默斯则认为，至少部分条件在危机前就出现了，而且很可能将持续更长时间。其中之一就是高收入经济体内私人部门投资的疲软。

 

The IMF’s point about slowing potential growth supports Mr Summers. Lower potential growth might then also be less sustainable growth. If so, we might find that the world economy is characterised by weak investment, low real and nominal interest rates, credit bubbles and unmanageable debt in the long term.

 

IMF有关潜在增长减缓的观点支持了萨默斯的看法。潜在增长率降低可能继而意味着增长的可持续性降低。如果确然如此，我们可能会发现全球经济在长期将以投资乏力、低实际利率和名义利率、信贷泡沫以及难以承担的债务为特点。

 

Such a disappointing future is not inevitable. But we cannot assume we will enjoy a brighter one. National, regional and global reforms are needed to accelerate potential growth and reduce instability. What form these might take is a subject for another day.

 

这样一个令人失望的未来并非不可避免。但我们不能臆断未来会更美好。必须进行国家、地区和全球改革，以加速潜在增长和减少不稳定。至于应该采取什么样的改革形式，择日再谈。