Can Planet Earth Feed 10 Billion People?。
地球能养活100亿人吗?
Humanity has 30 years to find out.。
人类还有30年的时间来寻找答案。
All parents remember the moment when they first held their children—the tiny crumpled face, an entire new person, emerging from the hospital blanket. I extended my hands and took my daughter in my arms. I was so overwhelmed that I could hardly think.。
所有的父母都记得他们第一次抱起孩子的那一刻——那张小小的、皱皱巴巴的脸,一个全新的人,从医院的毛毯中出现。我伸出双手,把我的女儿抱在怀里。我太不知所措了,简直难以想象。
Afterward I wandered outside so that mother and child could rest. It was three in the morning, late February in New England. There was ice on the sidewalk and a cold drizzle in the air. As I stepped from the curb, a thought popped into my head: When my daughter is my age, almost 10 billion people will be walking the Earth. I stopped midstride. I thought, How is that going to work?。
之后我在外面闲逛,这样妈妈和孩子就可以休息了。那时是凌晨3点,地点是2月下旬的新英格兰。人行道上有冰,空气中飘着冰冷的毛毛雨。当我沿着路边走下来的时候,一种想法突然出现在我的脑海里:当我的女儿到我现在的年纪时,差不多会有100亿人在地球上行走。我停止了散步。我在想,这是怎么回事?
In 1970, when I was in high school, about one out of every four people was hungry—“undernourished,” to use the term preferred today by the United Nations. Today the proportion has fallen to roughly one out of 10. In those four-plus decades, the global average life span has, astoundingly, risen by more than 11 years; most of the increase occurred in poor places. Hundreds of millions of people in Asia, Latin America, and Africa have lifted themselves from destitution into something like the middle class. This enrichment has not occurred evenly or equitably: Millions upon millions are not prosperous. Still, nothing like this surge of well-being has ever happened before. No one knows whether the rise can continue, or whether our current affluence can be sustained.。
1970年,当我上高中的时候,世界上每四个人中就有一个人处于饥饿状态——也就是“营养不良”——联合国用这个词来形容他们。如今,这一比例已降至约十分之一。在过去的四十年里,全球平均寿命的增加量超过了11年;大部分的增长都出现在贫困地区。亚洲、拉丁美洲和非洲的数亿人已经让自己脱离了贫困,变成了中产阶级。这种脱贫的进程并不是均匀或公平地发生的:还有无数的人仍然处于贫困的状态。然而,以前从未出现过这种幸福感的激增。没有人知道这一增长能否持续下去,也没有人知道我们目前的富裕能否持续下去。
Today the world has about 7.6 billion inhabitants. Most demographers believe that by about 2050, that number will reach 10 billion or a bit less. Around this time, our population will probably begin to level off. As a species, we will be at about “replacement level”: On average, each couple will have just enough children to replace themselves. All the while, economists say, the world’s development should continue, however unevenly. The implication is that when my daughter is my age, a sizable percentage of the world’s 10 billion people will be middle-class.。
今天,世界上大约有76亿居民。大多数人口学家认为,到2050年,这一数字将达到100亿,或者稍微少一点。到了这一时间,我们的人口可能会开始趋于平稳,作为一个物种,我们将处于“更替水平”:平均来说,每对夫妇将有足够的孩子来替换他们自己。一直以来,经济学家们都认为世界的发展应该会继续下去,无论发展是如何地不均衡。这意味着,当我的女儿达到我的年级时,世界上100亿人口中有相当一部分将是中产阶级。
Affluence is not our greatest achievement but our biggest problem.。
富裕不是我们最大的成就,而是我们最大的问题。
Like other parents, I want my children to be comfortable in their adult lives. But in the hospital parking lot, this suddenly seemed unlikely. Ten billion mouths, I thought. Three billion more middle-class appetites. How can they possibly be satisfied? But that is only part of the question. The full question is: How can we provide for everyone without making the planet uninhabitable?。
就像其他父母一样,我希望我的孩子在他们的成年生活阶段感到舒适。但在医院的停车场里,我觉得这似乎不太可能。我想,到时候将会有100亿张嘴。30亿中产阶级的胃。他们怎么可能会满意呢?但这只是问题的一部分。现在的问题是:我们如何才能在不让地球变得不适宜居住的情况下为所有人提供他们所需要的东西呢?
Van Gogh was born in a small Dutch village on March 30, 1853. Vincent started many jobs before he became an artist. He was real close to his family. In 1886, he moved to Paris, France to join Theo. Theo introduced Vincent to a lot of painters while they lived in Paris. Gauguin didn't seem to like anything Van Gogh did in Arles. They argued a lot. Gauguin decided to leave Van Gogh. He became so angry he cut off his ear. He did many other paintings before he shot himself and died two days later.。
大卫•李嘉图
(David Ricardo, 1772-1823)
The brilliant British economist David Ricardo was one of the most important figures in the development of economic theory. He articulated and rigorously formulated the "Classical" system of political economy. The legacy of Ricardo dominated economic thinking throughout the 19th Century. 。
David Ricardo's family was descended from Iberian Jews who had fled to Holland during a wave of persecutions in the early 18th Century. His father, a stockbroker, emigrated to England shortly before Ricardo's birth in 1772. David Ricardo was his third son (out of seventeen!). 。
At the age of fourteen, after a brief schooling in Holland, Ricardo's father employed him full-time at the London Stock Exchange, where he quickly acquired a knack for the trade. At 21, Ricardo broke with his family and his orthodox Jewish faith when he decided to marry a Quaker. However, with the assistance of acquaintances and on the strength of his already considerable reputation in the City of London, Ricardo managed to set up his own business as a dealer in government securities. He became immensely rich in a very short while. In 1814, at the age of 41, finding himself "sufficiently rich to satisfy all my desires and the reasonable desires of all those about me" (Letter to Mill, 1815), Ricardo retired from city business, bought the estate of Gatcomb Park and set himself up as a country gentleman. 。
Egged on by his good friend James Mill, Ricardo got himself elected into the British parliament in 1819 as an independent representing a borough in Ireland, which he served up to his death in 1823. In parliament, he was primarily interested in the currency and commercial questions of the day, such as the repayment of public debt, capital taxation and the repeal of the Corn Laws. (cf. Thomas Moore's poems on Cash, Corn and Catholics)。
Ricardo's interest in economics was sparked by a chance reading of Adam Smith's Wealth of Nations (1776) when he was in his late twenties. Bright and talkative, Ricardo discussed his own economic ideas with his friends, notably James Mill. But it was only after the persistent urging of the eager Mill that Ricardo actually decided to write them down. He began in 1809, authoring newspaper articles on currency questions which drew him into the great Bullionist Controversy that was raging at the time In that affair, he was a partisan of the Bullionist position, which argued for the resumption of the convertibility of paper money into gold. He wrote a pair of tracts (1810, 1811) articulating their arguments and outlining what has since become known as the "classical approach" to the theory of money.。
In these very same tracts, Ricardo also suggested the impossibility of a "general glut" -- an excess supply of all goods -- in an economy. This provoked the Rev. Thomas Robert Malthus to respond to Ricardo. The course of this debate continued in their extensive correspondence with each other, culminating in a series of notes Ricardo wrote on Malthus's 1820 Principles (these were later published posthumously as Notes on Malthus). Ricardo stood firm in his support of Say's Law and dismissed Malthus's underconsumption thesis as theoretically impossible. Yet, in spite of their disagreements on economic doctrines, they took to each other personally and fostered a legendary friendship. Ricardo even passed on investment tips to Malthus -- the most famous case being when Ricardo urged Malthus to invest in the bond market in anticipation of a British victory at Waterloo. Ever the conservative parson, Malthus declined. Ricardo, as usual, made a killing.。
In 1815, Ricardo published his groundbreaking Essay on..Profits. There he introduced the differential theory of rent and the "law of diminishing returns" to land cultivation. Coincidentally, this principle was discovered simultaneously and independently by Malthus, Robert Torrens and Edward West. (more astoundingly, all of them published their tracts within three weeks in February, 1815!) In his 1815 Essay, Ricardo formulated his theory of distribution in a one-commodity ("corn") economy. With wages at their "natural" level, Ricardo argued that rate of profit and rents were determined residually in the agricultural sector. He then used the concept of arbitrage to claim that the agricultural profit and wage rates would be equal to the counterparts in industrial sectors. With this theory, he could show that a rise in wages did not lead to higher prices, but merely lowered profits. 。
Arguably, a proper theory of value was missing in the 1815 tract. In a one-commodity model, this is not an big issue. But, prodded on by Malthus's criticisms, Ricardo realized that in a multiple-commodity economy, for rents and profits to remain residuals, then prices must be pinned down somewhere. In his formidable treatise, Principles of Political Economy and Taxation (1817), Ricardo finally articulated and integrated a theory of value into his theory of distribution. 。
For Ricardo, the appropriate theory was the "labor-embodied" theory of value or LTV, i.e. the argument that the relative "natural" prices of commodities are determined by the relative hours of labor expended in their production. Indeed, he began his 1817 book by criticizing Adam Smith's alternatives -- the "labor-commanded" and "adding up" theories of value -- because, he argued, that made value a function of wages and thus income distribution. For Ricardo, this was untenable. In his vision, value was independent of distribution, and thus only the "labor-embodied" theory made sense. 。
However, Ricardo realized that when the question of capital comes in, a problem arose: specifically, as different industries apply different amounts of capital per laborer, then the rate of profit will also differ across industries. Ricardo understood that if he then assumed that the rates of profit across different industries were equalized (as free competition would imply), then, mathematically, relative prices would now vary with wages -- exactly what he had criticized Smith for! Ricardo realized that the labor theory of value would only work if the degree of capital-intensity was the same across all sectors, casting doubt on the generality of his cherished theory. 。
Ricardo proposed two ways out of this dilemma. The first was the empirical argument that firms apply capital in a roughly proportional manner to the amount of labor invested. In this case, the resulting prices when profits are equalized would not differ much from the values implied by the LTV. This is what Stigler (1958) has called Ricardo's "93% labor theory of value". The second solution was to find a commodity which has the average capital per worker, so that its price would reflect labor-embodied value and thus not vary with changes in distribution. He called this the "invariable standard of value" . If one can find what this "standard" commodity is, Ricardo argued, then the rest of the analysis is simple. One can, say, change technology, trace the change in value of the standard commodity, and then extrapolate the change in value for all other commodities by the degree to which their capital composition deviates from this standard. Despite his search, Ricardo never found this standard commodity. On his death, an incomplete paper entitled "The Invariable Standard of Value" was found on his desk. Eventually, Karl Marx (1867) proposed one way out of it, but the proper solution would have to wait until Piero Sraffa (1960).。
A little tripped up on value, Ricardo (1817) pressed on nonetheless. With prices (more or less) pinned down by the LTV, he restated his old theory of distribution. Dividing the economy into classes of landowners (who spend their rental income on luxuries), workers (who spend their wage income on necessities) and capitalists (who save most of their profit income and reinvest it), Ricardo argued showed once again how the size of profits is determined residually by the extent of cultivation on land and the historically-given real wage. He then added on a theory of growth. Specifically, with profits determined in the manner given above, then the amount of capitalist saving, accumulation and labor demand growth could also be deduced. This, in turn, would increase population and thus bring more land, of less and less quality, into cultivation. As the economy continued to grow, then, by his theory of distribution, profits would be eventually squeezed out by rents and wages. In the limit, Ricardo argued, a "stationary state" would be reached where capitalists will be making near-zero profits and no further accumulation would occur.。
Ricardo suggested two things which might hold this law of diminishing returns at bay and keep accumulation going at least for a while: technical progress and foreign trade. On technical progress, Ricardo was ambivalent. One the one hand, he recognized that technical improvements would help push the marginal product of land cultivation upwards and thus allow for more growth. But, in his famous Chapter 31 "On Machinery" (added in 1821 to the third edition of his Principles), he noted that technical progress requires the introduction of labor-saving machinery. This is costly to purchase and install, and so will reduce the wages fund. In this case, either wages must fall or workers must be fired. Some of these unemployed workers may be mopped up by the greater amount of accumulation that the extra profits will permit, but it might not be enough. A pool of unemployed might remain, placing downward pressure and wages and leading to the general misery of the working classes. Technical progress, for Ricardo, was not a many-splendored thing.。
On foreign trade, Ricardo set forth his famous theory of comparative advantage. Using his famous example of two nations (Portugal and England) and two commodities (wine and cloth), Ricardo argued that trade would be beneficial even if Portugal held an absolute cost advantage over England in both commodities. Ricardo's argument was that there are gains from trade if each nation specializes completely in the production of the good in which it has a "comparative" cost advantage in producing, and then trades with the other nation for the other good. Notice that the differences in initial position mean that the labor theory of value is not assumed to hold across countries -- as it should be, Ricardo argued, because factors, particularly labor, are not mobile across borders. As far as growth is concerned, foreign trade may promote further accumulation and growth if wage goods (not luxuries) are imported at a lower price than they cost domestically -- thereby leading to a lowering of the real wage and a rise in profits. But the main effect, Ricardo noted, is that overall income levels would rise in both nations regardless. 。
With his 1817 treatise, Ricardo took economics to an unprecedented degree of theoretical sophistication. He formalized the Classical system more clearly and consistently than anyone before had done. For his efforts, he acquired a substantial following in Great Britain and elsewhere -- what became known as the "Classical" or "Ricardian" School. His system, however, was improved very little by his disciples. Perhaps only John Stuart Mill (1848) and Karl Marx (1867-94) added insights of any great weight.。
Ricardo's theory gradually fell out of favor, and died a slow death soon after the Marginalist Revolution of 1871-74. But research continued in some corners of the world, e.g. Vladimir Dmitriev (1898). Only much later did Piero Sraffa (1960) finally solve the "invariable measure of value" problem and re-ignited interest in Ricardo's theory. The "Neo-Ricardian" research program continues to advance today.。