After years in which $100 oil was the norm, the price of Brent crude is now around a third of that. Assume for a moment that Russia and Saudi Arabia fail in their efforts to get the price back up. Will $30 oil change the world? The answer is yes, of course. Everything is connected to everything else in economics, and that is particularly true when it comes to oil. For all the talk of the weightless economy, we’re not quite so post-industrial as to be able to ignore the cost of energy. Because oil is versatile and easy to transport, it remains the lubricant for the world’s energy system.

在许多年里，每桶石油在100美元以上是常态，如今，布伦特(Brent)原油价格只有那个水平的三分之一左右。假设俄罗斯与沙特阿拉伯短时间内无法让油价回升，每桶30美元的油价会改变世界吗？当然，答案是肯定的。在经济学中，一切因素都彼此关联——对石油来说就尤其如此了。虽然大家都在谈论“无重量经济”(weightless economy)，但我们的后工业化水平还没有达到可以忽略能源成本的程度。因为用途广泛且易于运输，石油仍是全球能源系统的润滑剂。

The rule of thumb has always been that while low oil prices are bad for the planet, they’re good for the economy. Last year a report from PwC estimated that a permanent fall in the price of oil by $50 would boost the size of the UK economy by about 1 per cent over five years, since the benefits — to most sectors but particularly to heavy industry, agriculture and air travel — would outweigh the costs to the oil production industry itself.

经验法则告诉我们，低油价虽然对地球不是好事，却有利于经济发展。去年，普华永道(PwC)发布的一份报告估计，油价长期性地跌去50美元，将使英国经济规模5年内扩张1%左右，因为低油价给大多数行业——尤其是重工业、农业及航空业——带来的好处将超过石油生产行业本身所遭受的损失。

That represents the conventional wisdom, as well as historical experience. Oil was cheap throughout America’s halcyon years of the 1950s and 1960s; the oil shocks of the 1970s came alongside serious economic pain. The boom of the 1990s was usually credited to the world wide web but oil prices were very low and they soared to record levels in the run-up to the great recession. We can debate how important the oil price fluctuations were but the link between good times and cheap oil is not a coincidence.

这既是一般观点也是历史经验。上世纪五、六十年代美国歌舞升平时期，油价始终都很便宜；70年代的石油危机伴随着严重的经济危机。90年代的繁荣通常被归功于互联网，其实油价当时很低，后来在“大衰退”前夕才飙升到了创纪录水平。我们可以争论油价波动的重要性，但繁荣时期与廉价石油之间的关联并非巧合。

Here’s a piece of back-of-the-envelope economics. The world consumes nearly 100 million barrels a day of oil, which is $10bn a day — or $3.5tn a year — at the $100 price to which we’ve become accustomed. A sustained collapse in the oil price would slice more than $2tn off that bill — set against a world economic output of around $80tn, that’s far from trivial. It is a huge transfer from the wallets of oil producers to those of oil consumers.

我们可以粗略地算一下：全世界每天消耗近1亿桶石油，按照我们习惯的每桶100美元计算，每天需要花费100亿美元，一年下来是3.5万亿美元。油价持续暴跌将使这笔开支减少逾2万亿美元，而与80万亿美元左右的世界经济产出相比，这并非微不足道。这是一笔从产油国转移至石油消费国的巨额财富。

Such large swings in purchasing power always used to boost economic growth, because while producers were saving the profits from high prices, consumers tended to spend the windfall from low ones. One of the concerns about today’s low prices is that the positions may be reversing: the big winners, American consumers, are using the spare cash to pay off debts; meanwhile, losers such as Russia and Saudi Arabia are cutting back sharply on investment and public spending. If carried to extremes, that would mean a good old-fashioned Keynesian slowdown in a world economy trying to spend less and save more; the more likely result of which is that lower oil prices fail to give us the boost we hope for.

购买力方面的大幅变动在过去通常会刺激经济增长，因为生产商会把从高价中获得的利润储蓄起来，而消费者则倾向于花掉从低价中节省下来的钱。当前低油价令人担忧的一个地方是，情况可能颠倒了过来：作为大赢家的美国消费者正在利用省下的钱偿还债务；与此同时，俄罗斯、沙特等输家正在大幅削减投资及公共支出。如果发展到极端，人们都试图减少开支、增加储蓄，世界经济将出现一场传统的凯恩斯式放缓；这样的后果是，低油价很可能无法带来我们期待的经济刺激效果。

It is intriguing to contemplate some of the less obvious effects. Charles Courtemanche, a health economist at Georgia State University, has found a correlation between low gasoline prices and high obesity rates in the United States. That is partly because, when oil prices are high, people may get out of their cars and walk, cycle or get public transport. Cheap gasoline, on the other hand, puts disposable income into the pockets of families who are likely to spend it on eating out. Low oil prices may make us fat.

低油价还有一些不那么明显的影响很是耐人寻味。乔治亚州立大学(Georgia State University)健康经济学家查尔斯•库特芒希(Charles Courtemanche)发现，美国汽油价格低企与高肥胖率之间存在相关性。部分原因在于，油价高时，人们可能减少开车，选择步行、骑自行车或乘坐公共交通工具。另一方面，廉价汽油为家庭节省了可支配收入，而他们很可能把这些钱花在外出就餐上。低油价可能会让我们变胖。

Another depressing possibility is that low oil prices will slow down the rate of innovation in the clean energy sector. The cheaper the oil, the less incentive there is to invent ways of saving it. There is clear evidence for this over the very long run. As recently as the late 1700s, British potters were using wasteful Bronze Age technology for their kilns. The reason? Energy was cheap. Wages, in contrast, were expensive — which is why the industrial revolution was all about saving labour, not saving energy.

另一个令人沮丧的可能性是，低油价会阻碍清洁能源领域的创新步伐。油价越便宜，发明新的节油方法的动力就越小。在这方面，历史上有明显的证据。18世纪头十年末期的时候，英国陶艺坊烧窑时使用的还是耗能很高的青铜时代的技术。原因何在？能源很便宜。相比之下，工资较高——这就是为什么工业革命的所有发明围绕的都是节约劳动力，而非节省能源。

More recently, David Popp, an economist at Syracuse University, looked at the impact of the oil price shocks of the 1970s. He found that inventors emerged from the woodwork to file oil-saving patents in fields from heat pumps to solar panels.

最近，锡拉丘兹大学(Syracuse University)经济学家大卫•波普(David Popp)研究了上世纪70年代石油危机造成的影响。他发现，当时大批发明家申请了从加热泵到太阳能电池板等领域的节油专利。

It is always possible that the oil price collapse will do little to affect some of the big technological shifts in the energy market. The scale of oil production from hydraulic fracturing (fracking) in the US may be curtailed but a huge technological leap has already happened. As the chief economist of BP, Spencer Dale, recently commented, fracking is starting to look less like the huge, long-term oil-drilling projects of the past, and more like manufacturing: cheap, lean, replicable and scalable. Low oil prices cannot undo that and the efficiencies may well continue. We can hope for ever-cheaper solar power too: photovoltaic cells do not compete closely with oil, and we may continue to see more and more installations and lower and lower prices.

始终存在这样的可能性，油价暴跌不会对能源市场中一些重大技术变革造成影响。在美国，利用水力压裂技术生产石油的规模可能有所缩减，但一场巨大的技术飞跃已经发生。英国石油(BP)首席经济学家斯宾塞•戴尔(Spencer Dale)最近称，水力压裂技术看起来已不再像过去那些庞大、长期的石油钻探项目，而开始更像制造业：廉价、精益、可复制、可扩展。低油价不会破坏这一进程，其效能将很好地延续下去。我们也可以寄希望于更廉价的太阳能：光伏电池还竞争不过石油，我们或许将看到越来越多的太阳能设备，以及越来越低的太阳能电价。

That said, when fossil fuels are cheap, people will find ways to burn them, and that’s gloomy news for our prospects of curtailing climate change. We can’t rely on high oil and coal prices to discourage consumption: the world needs — as it has needed for decades — a credible, internationally co-ordinated tax on carbon.

尽管如此，当化石燃料价格较低时，人们会找到各种方法利用它们，这对我们减缓气候变化的前景来说不是好消息。我们不能依靠高昂的石油和煤炭价格来抑制消费：世界需要（几十年来一直需要）一个可靠的、国际协调的碳税体系。

Wall Street analysts have slashed expectations for US earnings in the first quarter as companies grapple with plummeting oil prices and slow economic growth.

华尔街分析师大幅调降了对第一季度美国企业盈利的预期，原因是油价暴跌和经济增长放缓令企业难以应对。

The growing pessimism comes amid a brutal start to the year for the stock market during which the S&P 500 has been marked by volatility as the outlook for global economic growth darkens, led by uncertainty over the slowdown in China.

人们的悲观情绪越来越强烈之际，随着全球经济增长前景变得黯淡（尤其是中国经济放缓带来不确定性），股市今年出现了极为糟糕的开局，标普500(S&P 500)指数出现了大幅波动。

At the outset of the year, analysts had forecast a return to growth of 0.6 per cent in US first-quarter earnings per share on a year-on-year basis, according to FactSet. They have since marked estimates down to a decline of 7.4 per cent.

根据FactSet的数据，今年伊始分析师们预计美国第一季度每股盈利会恢复增长，同比增幅达到0.6%。自那以来，他们已经把盈利估计下调至降低7.4%。

“It does appear that companies are having difficulty gaining traction in this low-growth environment and that is putting downward pressure on earnings,” said Alan Gayle, director of asset allocation at RidgeWorth Investments.

RidgeWorth Investments资产配置主任艾伦•盖尔(Alan Gayle)表示：“企业在这种低增长环境下似乎难以获得增长动力，这给企业盈利带来了下行压力。”

The potential quarter of shrinking profits follows the worst earnings season since the aftermath of the financial crisis during which earnings have fallen for three consecutive quarters and revenues have fallen for four.

在这一企业利润可能缩水的季度之前，美国遭遇了自金融危机爆发以来的最差业绩报告季，企业盈利连续三个季度下跌，营收连续四个季度下滑。

Early forecasts that 2016 would provide a turnround have been re-evaluated largely because of an expected earnings drop of 93 per cent at energy companies, as the price of crude oil dropped to a 13-year low. That is nearly double the decrease analysts had projected for the sector two months ago.

起初，人们曾预计2016年会出现止跌回升的现象。然而，这一预期已在很大程度上被重新评估，原因是能源企业因原油价格跌至13年低点而致预期盈利下滑93%，这一下跌幅度几乎是分析师们两个月前对该产业预计降幅的两倍。

Forecasts were for revenues for S&P 500 companies to shrink 0.6 per cent, while at year-end analysts were looking for growth of 2.6 per cent.

对标普500成分股企业的预期是营收缩水0.6%，而在去年年底分析师曾预计会增长2.6%。

Russ Koesterich, chief investment strategist at BlackRock, said: “We have a world where global growth is expected to have come down, financial market conditions have tightened and energy prices have fallen further. All of these are headwinds at the market level and not a great environment to grow the top line.”

贝莱德(BlackRock)首席投资策略师拉斯•凯斯特里奇(Russ Koesterich)表示：“我们面临的是一个全球增长预计将会放缓、金融市场状况趋紧、能源价格进一步下滑的世界。所有这些都是市场层面上的不利因素，对营收的增长十分不利。”

Neither top nor bottom line growth is expected to return until the second half of the year and investors say the worsening outlook could mean further stock market declines.

预计不论营收还是利润，在今年下半年以前都不会恢复增长。投资者表示，不断恶化的前景可能意味着股市会进一步下跌。

“Sentiment has stabilised recently,” Mr Gayle said. “The negative revisions I don’t think have really sunk in. From that perspective, I think there is more downside risk in the market as we get closer to first-quarter earnings season.”

“市场情绪最近已趋于稳定。”盖尔表示。“我认为这些负面的下调还未真正被人们认识到。从这个角度来说，我认为随着一季度业绩公布季节日益临近，市场还存在更多下行风险。”

Companies have also disappointed investors with their own outlooks.

企业自身的前景展望也令投资者失望。

About 110 companies in the index have issued EPS guidance for the first quarter with 88 issuing projections below analysts’ expectations, worse than the five-year average of 72 per cent.

标普500指数的成分股企业中，大约有110家企业发布了第一季度每股盈利指引，其中88家企业发布的预期低于分析师的预测，这一比例高于72%的五年平均。