美媒预测：中国2020年或赶超美国

I have long argued that it is more or less inevitable that China's economy will in a not too distant future become the biggest in the world. I am more convinced than ever of the truth of this prediction.
Each year it seems, China passes at least one new milestone. In 2008, it surpassed Germany to become the third biggest economy. In 2009, it surpassed Germany as the biggest exporter and America as the biggest car market. In 2010, it will (barring a really dramatic yen appreciation) surpass Japan as the second biggest economy.
But exactly when will China surpass America as the world's biggest economy? Obviously, we can't for sure pinpoint the exact year it will definitely happen. But we can pinpoint using basic arithmetic just when it is likely to happen. And the numbers clearly suggest that old estimates that the shift won't happen until 2040 or 2050 are far off the mark.
In 2009, nominal GDP in America was according to preliminary estimates, $14.26 trillion. In China, nominal GDP was 34.05 trillion yuan, or $4.98 trillion using the average 2009 exchange rate. That means that America's GDP was 2.86 times bigger.
With average annual growth in America being some 7.5 percentage points lower during the 2000s, then assuming that this will continue and that the real exchange rate of the yuan will appreciate by on average 3 percent per year (quite reasonable)， then it will only take 11 years before the Chinese economy becomes bigger, meaning that by 2020, China's economy will be the biggest in the world.
If we assume that the growth differential falls to just 5 percent, while the estimated real appreciation is assumed to be just 2.5 percent per year, then China's economy will become bigger by 2024.
Given the falling returns from the "catch-up effect" that naturally follows when a nation becomes richer, it is unreasonable to assume that the growth differential of the last decade will last forever, or even for several more decades.
But since per capita income would still be much lower in China when its economy are as big as America given it's much bigger population, it is quite reasonable to expect a similar growth differential for a while, and to expect a significant real appreciation of the yuan, making it likely that the year when China will become biggest somewhere between 2020 and 2025.

长久以来，我一直认为中国经济在不太遥远的未来成为世界最大经济体几乎是不可避免的。如今我比以往更相信这个预测是正确的。
每一年，中国似乎都至少超越一个新的里程碑。2008年，它超越德国成为世界第三大经济体。2009年，它超越德国成为世界头号出口国，又超过美国成为最大汽车市场。2010年它将超过日本成为世界第二大经济体。
但是，中国究竟何时超越美国成为世界最大经济体呢？显然我们无法确定其发生的确切年份，但我们能够利用基本数学运算来推算何时最可能发生这种情况。而各种数据表明，关于这种转变直到2040年或2050年才会发生的原先估计错得太离谱了。
2009年美国的名义GDP是14.26万亿美元，中国的是34.05万亿元人民币，按2009年的平均汇率折算为4.98万亿美元。这意味着美国的GDP只是中国的2.86倍。
由于在21世纪的头10年，(与中国相比)美国经济年平均增长率低了大约7.5个百分点，假设这一趋势继续下去，且人民币汇率年均升值3%(这是相当合理的)，那么只需11年时间，中国经济就会变得比美国更强大，这意味着到2020年时中国将成为第一大经济体。
如果我们假定增长差距缩小至只有5%，同时人民币升值幅度每年只有2.5%，那么到2024年时中国经济将超过美国。
考虑到随着国家变得越来越富裕，“追赶效应”在递减，想当然地认为过去10年来的这种增长差距将永远持续———或持续几十年———就显得不合理了。
但是，当中国经济规模和美国一样大时，考虑到中国人口更多，人均收入仍将低得多，预计相似的增长差距仍将持续一段时间是相当合理的，预计人民币将真正大幅升值也是相当合理的，这极有可能使中国在2020年到2025年之间的某个时候成为世界上最大经济体。