We Can Lower Oil Prices Now
2008年07月03日09:01
尽管大多数专家都认为，金融投机活动并不是推动全球食品与能源价格飙升的罪魁祸首，但许多人仍然对物价显著上涨的根源感到困惑。关于这个问题，经济学从供求关系的角度提出了简单解释，并对大宗商品价格未来走势提供了乐观的理由。具体到油价问题，经济学分析揭示了对未来产生影响的当前政策调整又是如何反过来迅速促使当前油价回落的。
Although most experts agree that financial speculation was not responsible for the surge in the global prices of food and energy, many people remain puzzled about the source of these remarkable price rises. Economics offers a simple supply-and-demand explanation and reason for optimism about the future of commodity prices. In the case of oil, economics also suggests how policy changes today that affect the future could quickly lower the current price of oil.
众所周知，中国、印度与海湾国家的收入增长带动了石油与其他许多大宗商品的需求上扬。但这种温和短期的需求增长如何能导致石油等大宗商品价格上涨高达一倍？让我们首先看看易腐农产品的情况。
We all know that rising incomes in China, India and the Gulf states have increased the demand for oil and many other commodities. But how could the modest, one-year rise of these demands lead to 100% increases in the prices of oil and other commodities? Let's take a look first at perishable agricultural commodities.
与需求的全球性增长相比，短期内玉米供应的增长空间有限。从市场的供求平衡方面来说，玉米价格必须上涨。
In the short run, there is little scope for increasing the supply of corn in response to a global increase in demand. For demand and supply to balance -- for the market to clear -- the price of corn must rise.
如果玉米需求对价格变化非常敏感，那么很小的价格上涨就会引起全球需求下降足够的幅度，从而抵消当初的需求增长。但是，由于短期内需求实际上对价格十分不敏感，因此就需要非常明显的价格上涨才能使全球需求与供应保持一致。
If the demand for corn were very price-sensitive, a relatively small increase in price would reduce global demand by enough to offset the initial rise in demand. However, since demand is actually quite insensitive to price in the short run, it takes a very large price rise to bring global demand into line with supply.
下面是去年发生的状况的一个简化模型。高增长国家的玉米需求数量稳步增长，增幅最终达到了相当于此前全球玉米总消费量的10%。由于玉米供应没有跟着增长，因此价格不得不上涨一定程度，从而促使其他国家的玉米消费量下降10%。如果价格上涨10%才能推动头年玉米需求下降1%，那么价格就需要上涨一倍，才能抵消玉米需求最初增长的10%。
Here is a simplified picture of what happened in the past year. The quantity of corn demanded by high-growth countries rose gradually, increasing eventually by an amount equal to, say, 10% of the previous total global level of corn consumption. Since the supply of corn did not increase, the price had to increase enough to reduce corn consumption in other countries by 10%. If it takes a 10% increase in the price to reduce the quantity of corn demanded in the first year by just 1%, it would take a 100% increase in the price of corn to offset the initial 10% rise in the quantity of corn demanded.
实际上，在供求两个方面都有不同农产品作替换，加之玉米乙醇项目的实施，导致上述简单的关系变得复杂化。但基本原理并没有变：由于短期内需求对价格变化非常不敏感，短期供应提升空间有限，因此即使高增长经济体的玉米需求出现相当小的增长，都会导致玉米价格出现非常明显的短期上涨。
In reality, the picture is complicated by the substitution in both supply and demand among different agricultural commodities, and by the role of the corn ethanol program. But the basic explanation holds: With a very low short-run price sensitivity of demand and little scope to raise supply in the short run, even a relatively small increase in corn demand by the high-growth economies can lead to a very large short-run rise in the price of corn.
幸运的是，需求与供应的价格敏感性都会随着时间逐渐上升。这意味着，尽管中国等国家的需求不断增长，但玉米价格最终可能会较当前水平有所回落。
Fortunately, the price sensitivity of both demand and supply will increase with time. This implies that the rising demand from China and other countries may eventually be accommodated with a price lower than today's level.
油价的状况更为复杂，但价格变化的结果可能会更加有利。
The situation for oil is more complex, but the outcome for prices is potentially more favorable.
不同于易腐烂的农产品，石油可以长期埋在地下。因此让我们想想，一个产油商何时会降低产量或增加库存，而不是出售石油并将所得变成可投资现金呢？简单的说，如果产油商估计油价涨幅高于售油所得资金的利息，那么他们就情愿将石油留在地下以待日后开采。实际油价涨势可能会快于或慢于预期，但出售或是持有石油则取决于油价预期涨势。
Unlike perishable agricultural products, oil can be stored in the ground. So when will an owner of oil reduce production or increase inventories instead of selling his oil and converting the proceeds into investible cash? A simplified answer is that he will keep the oil in the ground if its price is expected to rise faster than the interest rate that could be earned on the money obtained from selling the oil. The actual price of oil may rise faster or slower than is expected, but the decision to sell (or hold) the oil depends on the expected price rise.
当然，影响产油商决定从而左右油价走势的因素还有风险方面的考虑，以及价格变化对长期消费行为的影响。拥有强大定价能力的石油输出国组织(OPEC，简称欧佩克)仍然发挥着重要作用。但基本点是，产油国会调整其开采与库存水平，直至油价预计会以利息水平上涨（经风险因素调整）。如果他们预计油价会加速上涨，他们就会将石油留在地下日后开采。反过来，如果预计油价涨幅不及利息，这些产油商就会提高产量，用售油资金进行投资。
There are of course considerations of risk, and of the impact of price changes on long-term consumer behavior, that complicate the oil owner's decision -- and therefore the behavior of prices. The Organization of Petroleum Exporting Countries (the OPEC cartel), with its strong pricing power, still plays a role. But the fundamental insight is that owners of oil will adjust their production and inventories until the price of oil is expected to rise at the rate of interest, appropriately adjusted for risk. If the price of oil is expected to rise faster, they'll keep the oil in the ground. In contrast, if the price of oil is not expected to rise as fast as the rate of interest, the owners will extract more and invest the proceeds.
未来与当前油价之间的关系显示，未来油价的预期变化会对当前油价产生直接影响。
The relationship between future and current oil prices implies that an expected change in the future price of oil will have an immediate impact on the current price of oil.
由此可推，当产油商认定未来数年中国与其他一些国家的石油需求会较此前预期加速增长时，他们就会认为未来油价会高于此前预期的水平。因此，这些产油商会降低供应，使得现货价格上涨足够的幅度，从而推动预期价格涨势回落到最初水平。
Thus, when oil producers concluded that the demand for oil in China and some other countries will grow more rapidly in future years than they had previously expected, they inferred that the future price of oil would be higher than they had previously believed. They responded by reducing supply and raising the spot price enough to bring the expected price rise back to its initial rate.
因此，在当前石油需求状况没有变化的情况下，对未来需求增长以及油价上涨的预期导致了当前油价走高。与此类似，对俄罗斯与墨西哥未来产量下滑的可信报告也暗示，未来全球油价会进一步上涨；这也需要当前油价走高，保证油价维持最初的预期涨幅。
Hence, with no change in the current demand for oil, the expectation of a greater future demand and a higher future price caused the current price to rise. Similarly, credible reports about the future decline of oil production in Russia and in Mexico implied a higher future global price of oil -- and that also required an increase in the current oil price to maintain the initial expected rate of increase in the price of oil.
一旦理解其中关系，就很容易明白那些新闻报导、传言与行业报告导致当前油价出现大幅波动的原因了──即使当前供求并没有发生任何变化。
Once this relation is understood, it is easy to see how news stories, rumors and industry reports can cause substantial fluctuations in current prices -- all without anything happening to current demand or supply.
当然，由未来油价预期引发的现货油价上涨会促使当前石油需求量下降。如果当前石油供求一开始处于平衡状态，欧佩克与其他产油国就会减少石油供应，使得供应与暂时下降的需求保持一致。未来石油需求增长的预期因此会导致当前石油供应出现下降。这正是2007年沙特阿拉伯等国家减产的原因。
Of course, a rise in the spot price of oil triggered by a change in expectations about future prices will cause a decline in the current quantity of oil that consumers demand. If current supply and demand were initially in balance, the OPEC countries and other oil producers would respond by reducing sales to bring supply into line with the temporary reduction in demand. A rise in the expected future demand for oil thus causes a current decline in the amount of oil being supplied. This is what happened as the Saudis and others cut supply in 2007.
并不只有坏消息。任何引起未来预期油价下跌的政策都会导致当前油价下跌，或促使油价涨势出现回落。换句话说，通过政策推动当前油价回落是有可能的，只要这些政策能够对未来的供应或需求产生实际影响。
Now here is the good news. Any policy that causes the expected future oil price to fall can cause the current price to fall, or to rise less than it would otherwise do. In other words, it is possible to bring down today's price of oil with policies that will have their physical impact on oil demand or supply only in the future.
例如，提高对汽车节能技术研发的政府补贴，或是严格标准逐步提高汽车的汽油里程数，都可以降低未来的石油需求，进而促使目前的油价回落。
For example, increases in government subsidies to develop technology that will make future cars more efficient, or tighter standards that gradually improve the gas mileage of the stock of cars, would lower the future demand for oil and therefore the price of oil today.
与此类似，未来石油供应上涨的预期也可以推动当前油价回落。而当前油价下跌会随即推动石油消费增长，促使欧佩克成员国以及其他当前拥有过剩产能或可用库存的产油国提高供应量，推动供求关系恢复平衡。
Similarly, increasing the expected future supply of oil would also reduce today's price. That fall in the current price would induce an immediate rise in oil consumption that would be matched by an increase in supply from the OPEC producers and others with some current excess capacity or available inventories.
只要我们目前能够采取措施提高未来石油供应，或降低美国与其他国家的未来需求，都可以促使当前油价回落，并提振消费。
Any steps that can be taken now to increase the future supply of oil, or reduce the future demand for oil in the U.S. or elsewhere, can therefore lead both to lower prices and increased consumption today.
Martin Feldstein
（编者按：本文作者马丁?费尔德斯坦(Martin Feldstein)曾在里根(Reagan)总统执政时期担任经济顾问委员会(Council of Economic Advisers)主席，现任哈佛大学教授、《华尔街日报》投稿委员会成员。）>
(Editor's Note: Mr. Feldstein, chairman of the Council of Economic Advisers under President Reagan, is a professor at Harvard and a member of The Wall Street Journal's board of contributors.)
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