经济学人(英语文章带翻译)
Nice work if you can get out 谁都不愿摊上这种好事
Free exchange自由交流
Why the rich now have less leisure than the poor
为什么当今富人的休闲时间比穷人还少
Apr 19th 2014 | From the print edition
1 FOR most of human history rich people had the most leisure. In ―Downton Abbey‖, a drama ab out the British upper classes of the early 20th century, one aloof aristocrat has never heard of the term ―weekend‖: for her, every day is filled with leisure. On the flip side, the poor have typically slogged.
Hans-Joachim Voth, an economic historian at the University of Zurich, shows that in 1800 the average English worker laboured for 64 hours a week. ―In the 19th century you could tell how poor somebody was by how long they worked,‖ says Mr Voth.
‖2 In today's advanced economies things are different. Ov erall working hours have fallen over the past century. But the rich have begun to work longer hours than the poor. In 1965 men with a college degree, who tend to be richer, had a bit more leisure time than men who had only completed high school. But by 2005 the college-educated had eight hours less of it a week than the
high-school grads. Figures from the American Time Use Survey, released last year, show that Americans with a bachelor's degree or above work two hours more each day than those without a high-school diploma. Other research shows that the share of college-educated American men regularly working more than 50 hours a week rose from 24% in 1979 to 28% in 2006, but fell for high-school dropouts. The rich, it seems, are no longer the class of leisure.
3 There are a number of explanations. One has to do with what economists call the ―substitution effect‖. Higher wages make leisure more expensive: if people take time off they give up more money. Since the 1980s the salaries of those at the top have risen strongly, while those below the median have stagnated or fallen. Thus rising inequality encourages the rich to work more and the poor to work less.
，4 The ―winner-takes-all‖ nature of modern economies may amplify the substitution effect. The scale of the global market means businesses that innovate tend to reap huge gains (think of YouTube, Apple and Goldman Sachs). The returns for beating your competitors can be enormous. Research from Peter Kuhn of the University of California, Santa Barbara, and Fernando Lozano of Pomona College shows that the same is true for highly skilled workers. Although they do not immediately get overtime pay for ―extra‖ hours, the most successful workers, often the ones putting in the most hours, may reap gains from winner-takes-all markets. Whereas in the early 1980s a man working 55 hours a week earned 11% more than a man putting in 40 hours in the same type of occupation, that gap had increased to 25% by the turn of the 5 Economists tend to assume that the substitution effect must at some stage be countered by an ―income effect‖: as higher wages allow people to satisfy
more of their material needs, they forgo extra work and instead choose more leisure. A billionaire who can afford his own island has little incentive to work that extra hour. But new social mores may have flipped the income effect on its head.
6 The status of work and leisure in the rich world has changed since the days of ―Downton Abbey‖. Back in 1899 Thorstein Veblen, an American economist who dabbled in sociology, offered his take on things. He argued that leisure was a ―badge of honour‖. Rich people could get others to do the dirty, repetitive work—what Veblen called ―industry‖. Yet Veblen's leisure class was not idle. Rather they engaged in ―exploit‖: challen ging and creative activities such as writing, philanthropy and debating.
7 Veblen's theory needs updating, according to a recent paper from researchers at Oxford University*. Work in advanced economies has become more knowledge-intensive and intellectual. There are fewer really dull jobs, like lift-operating, and more glamorous ones, like fashion design. That means more people than ever can enjoy ―exploit‖ at the office. Work has come to offer the sort of pleasures that rich people used to seek in their time off. On the flip side, leisure is no longer a sign of social power. Instead it symbolises uselessness and unemployment.
8 The evidence backs up the sociological theory. The occupations in which people are least happy are manual and service jobs requiring little skill. Job satisfaction tends to increase with the prestige of the occupation. Research by Arlie Russell Hochschild of the University of California, Berkeley, suggests that as work becomes more intellectually stimulating, people start to enjoy it more than home life. ―I come to work to relax,‖ one interviewee tells Ms Hochschild. And wealthy people often feel that lingering at home is a waste of time. A study in 2006 revealed that Americans with a household income of more than $100,000 indulged in 40% less ―passive leisure‖ (such as watching TV) than those earning less than $20,000.
Condemned to relax
休闲是无奈之举
9 What about less educated workers? Increasing leisure time probably reflects
a deterioration in their employment prospects as low-skill and manual jobs have withered. Since the 1980s, high-school dropouts have fared badly in the labour market. In 1965 the unemployment rate of American high-school graduates was 2.9 percentage points higher than for those with a bachelor's degree or more. Today it is 8.4 points higher. ―Less educated people are not necessarily buying their way into leisure,‖ explains Erik Hurst of the University of Chicago. ―Some of that time off work may be involuntary.‖ There may also be change in the income effect for those on low wages. Information technology, by opening a vast world of high-quality and cheap home entertainment, means that low-earners do not need to work as long to enjoy a reasonably satisfying leisure.
从历史上来看，但凡富人都是最闲的。在讲述20世纪初期英国上层社会的电视剧《唐顿庄园》中，一位冷漠的贵族从未听说过“周末”一词：对她来说，每天都有大把的闲暇时间。相比之下，穷人则是典型地终日劳作。苏黎世大学的经济史专家汉斯-约阿希姆?沃斯说，在1800年时，英国工人每周的平均工作时间为64个时。“判断一个人是有钱还是没钱，只要看他的工作时间就可以了。
在当今的发达经济体中，情况依然发生了变化。在过去的一个世纪中，整体的工作时间一直在减少。但是，富人的工作时间已经开始超过穷人。在1965年时，拥有大学学位的人——他们往往容易成为比较富有的人——还能比仅仅上完高中的人多享受一点闲暇时间。但是，到2005年时，他们每周的闲暇时间反而比后者减少了8个小时。据去年发布的《美国时间利用调查报告》显示，在美国，相比没有高中文凭的人，拥有学士学位及学士学位以上的人，每天要多工作2个小时。其他的调查显示，在每周工作时间通常超过50个小时的美国人中，拥有大学文凭的比例已经从1979年的24%上升到2006年的28%。相比之下，没有读完高中的人在其中所占的比例一直处于下降的趋势。由此看来，富人已经不再是有闲一族了。
这种变化可以从多个方面来解释。其中之一同经济学家所说的“替代效应”有关。工资越高，闲暇的代价就越大；想休班，就得牺牲挣钱的机会。自上世纪80年代以来，顶层的收入迅猛增长，而低于中位数的人群的收入要么处于裹足不前
要么有所下降。于是，日趋严重的不平等就会鼓励富人多工作，穷人少工作。millennium.
当代经济“赢者通吃”的特点可能会放大替代效应。市场的大小决定了挣钱的多少。在全球化时代，创新往往能带来巨额的利润。（在这方面，YouTube、苹果和高盛都是绝好的例子。）打败竞争对手的回报可能是巨大的。研究显示，对于高技能工人来说，情况同样如此。尽管他们不会因为“额外”工作时间比别人多而立即得到超额的报酬，但是最为成功的工人——通常是那些将大部分时间投入到工作中的人——可能会从赢者通吃的市场获得高额的回报。上世纪80年代初期，在从事同一种职业的人中，每周工作55个小时的人的工资比每周工作40个小时的多11%；到2000年时，这一差距已经拉大到25%。
在经济学家看来，替代效应必然会在某个阶段遭遇“收入效应”的阻击：工资的提高允许人们去满足更多的物质需求。为此，他们会放弃加班，更多地选择休闲。买得起私人岛屿的百万富翁是没有加班的动力的。但是，新的社会风尚可能会令收入效应产生逆转。
自“唐顿庄园”时代以来，在富国中，工作与休闲的位置就已经发生了逆转。回到1899年，亦涉足社会学的美国经济学家托斯丁·韦布伦曾给出过自己的解释。他说，闲暇是一种“荣誉勋章”。富人可以让别人去干脏活和重复性的劳动——这就是韦布伦所谓的“工业”。然而，有闲一族是不能无所事事的。相反，他们应当致力于“开拓”，从事类似于写作、慈善和辩论等具有挑战性和创新性的工作。
根据牛津大学研究者的最新论文，韦布伦的理论需要更新了。在发达经济体中，工作已经变得更加依赖于知识和智力。像开电梯这样的真正无聊的工作已经越来越少，而像时装设计这样的有吸引力的工作却越来越多。也就是说，能够在办公室中享受“开拓”的人正在日益增加。工作已经开始提供富人常常在闲暇的时候去追求的那种休闲。反过来说，闲暇已经不再是社会地位的象征。相反，它所
代表的是毫无用处和失业。
这些证据是有社会学理论来支撑的。人们最不乐意从事的职业是体力劳动和对技能要求不高的服务性工作。工作满意度会随着职业的优越性而增加。加州大学伯克利分校的霍奇柴尔德指出，随着工作更多地由知识来推动，人们开始享受工作甚于享受休闲。一位受访者告诉霍奇柴尔德：“我工作的目的，就是为了放松”。与此同时，富人也经常会产生一种“在家闲着就是浪费时间”的认识。2006年的一份研究表明，家庭收入超过1000000美元的美国人沉湎于“被动休闲”（如看电视）的时间比家庭收入不足20000美元的少40%。
那么受教育程度较低的工人又是什么情况呢？随着低技能工作和体力劳动的逐渐萎缩，闲暇时间的增加可能反映了就业前景的恶化。自上世纪80年代以来，高中辍学者在劳动力市场上的待遇一直不好。1965年时，拥有高中文凭的美国人的失业率比拥有学士学位或学士学位以上的高出2.9个百分点。如今，这一数字上升到8.4个百分点。芝加哥大学的埃里克·赫斯特解释说：“受教育程度低的人是不必花钱买闲暇的，有些闲暇时间可能是非自愿性的。”收入效应对低收入者的影响也可能发生了变化。信息技术在为我们打开了一个高质量低收费的家庭娱乐之广阔世界的同时，也意味着低收入者不必为了享受合理的称心如意的闲暇而去长时间地工作
The once and future currency 美元—曾经的和未来的货币
Free exchange自由交流
The once and future currency
曾经的和未来的货币
A new book examines the world's love-hate relationship with the dollar 新书探讨了全世界与美元之间的爱恨情仇
Mar 8th 2014 | From the print edition
1―LUMPY, unpredictable, potentially large‖: that was how Tim Geithner, then head of the New York Federal Reserve, described the need for dollars in emerging economies in the dark days of October 2008, according to transcripts of a Fed meeting released last month. To help smooth out those lumps, the Fed offered to ―swap‖ currencies with four favoured central banks, as far off as South Korea and Singapore. They could exchange their own money for dollars at the prevailing exchange rate (on condition that they later swap them back again at the same rate). Why did the Fed decide to reach so far beyond its shores? It worried that stress in a financially connected emerging economy could eventually hurt America. But Mr Geithner also hinted at another motive. ―The privilege of being the reserve currency of the world comes with some burdens,‖ he said.
2 That privilege is the subject of a new book, ―The Dollar Trap‖, by Eswar Prasad of Cornell University, who shares the world's ambivalence towards the currency. The 2008 financial crisis might have been expected to erode the dollar's global prominence. Instead, he argues, it cemented it. America's fragility was, paradoxically, a source of strength for its currency.
3 In the last four months of 2008 America attracted net capital inflows of half a trillion dollars. The dollar was a haven in tumultuous times, even when the
tumult originated in America itself. The crisis also ―shattered conventional views‖ about the adequate level of foreign-exchange reserves, prompting emerging economies with large dollar hoards to hoard even more. Finally, America's slump forced the Fed to ease monetary policy dramatically. In response, central banks in emerging economies bought dollars to stop their own currencies rising too fast.
4 Could Fed swap lines serve as a less costly alternative to rampant reserve accumulation? If central banks could obtain dollars from the Fed whenever the need arose, they would not need to husband their own supplies. The demand is there: India, Indonesia, the Dominican Republic and Peru have all made inquiries. The swap lines are good business: the Fed keeps the interest from the foreign central bank's loans to banks, even though the other central bank bears the credit risk. The Fed earned 6.84% from South Korea's first swap, for example. But it is not a business the Fed wants to be in. As one official said, ―We're not advertising.‖
5 Swap lines would help emerging economies endure the dollar's reign. But will that reign endure? Mr Prasad thinks so. The doll ar's position is ―suboptimal but stable and self-reinforcing,‖ he writes. Much as Mr Prasad finds America's privileges distasteful, his book points to the country's qualifications for the job.
6 America is not only the world's biggest economy, but also among the most sophisticated. Size and sophistication do not always go together. In the 1900s the pound was the global reserve currency and Britain's financial system had the widest reach. But America was the bigger economy. In the 2020s China will probably be the world's biggest economy, but not the most advanced.
7 America's sophistication is reflected in the depth of its financial markets. It is unusually good at creating tradeable claims on the profits and revenues that its economy generates. In a more primitive system, these spoils would mostly accrue to the state or tycoons; in America, they back a vast range of financial assets.
8 Mr Prasad draws the obvious contrast with China and its currency, the yuan,
a ―widely hyped‖ alternative to the dollar. China's GDP is now over half the size of America's. But its debt markets are one-eighth as big, and foreigners are permitted to own only a tiny fraction of them. China's low central-government debt should be a source of strength for its currency. But it also limits the volume of financial instruments on offer.
9 America has a big external balance-sheet, if not an obviously strong one. Its foreign liabilities exceed its overseas assets. But this worrying fact conceals a saving grace: its foreign assets are unusually adventurous and lucrative. Its liabilities, on the other hand, are largely liquid, safe and low-yielding. America therefore earns more on its foreign assets than it pays on its foreign liabilities.
10 Alongside its economic maturity, America also has a greying population. This ageing is a source of economic weakness. But, Mr Prasad argues, it may be another reason for the dollar's global appeal. America's pensioners hold a big chunk of the government debt that is not held by foreigners. A formidable
political constituency, they will not allow the government to inflate away the value of these claims. Thus America's powerful pensioners serve to protect the interests of its generous foreign creditors.
11 America's sophistication has one final implication: the dollar has no
long-term tendency to strengthen. That again contrasts with its principal
long-run rival. China is still a catch-up economy. As it narrows the productivity gap with America, its exchange rate, adjusted for inflation, will tend to rise. The yuan has appreciated by about 35% against the dollar since mid-2005.
A self-deprecating currency一种自我贬值的货币
12 The dollar's depreciation over that period is, of course, bad for anyone holding American assets. But the dollar is not merely a store of value. It has also become a popular ―funding‖ currency. Banks and multinational firms borrow in dollars, even as they accumulate assets in other denominations. Since no one wants to borrow in a currency that only goes up, this is not a role that China's currency could easily play. Moreover, because of its role as a funding currency, the dollar tends to strengthen in times of crisis. That explains why emerging economies feel a ―lumpy‖, ―unpredictable‖ need for dollars. America's currency may not hold its value against others. But in times of stress, the appeal of a dollar asset is that it always holds its value against a dollar debt. The dollar is a global hegemon partly because it is also a global hedge.
“成批的、不可预测的、可能会非常大的，”据上个月公布的美联储会议记录，这是时任纽约联邦储备银行行长蒂姆·盖特纳在描述新兴经济体在2008年10月最黑暗的那几天中对于美元的需要时曾经说过的一句话。为了帮助消除那些成批的需求，美联储提出，可以为包括远在韩国央行和新加坡央行在内的四家关系较好的央行提供货币“交换”。这四家央行可以用它们自己的货币以现行汇率换成美元（其前提条件是，它们在以后还要用相同的汇率将美元换回自己的货币）美联储为何要决定将其影响力扩展到离美国这么远的国家呢？[原因在于，]它担心金融联系密切相关的新兴世界的压力可能最终会伤害美国。不过，盖特纳还暗示了美联储的另一个动机。“成为世界储备货币后，在享有特权的同时也得承担某些责任，”他说道。
这种特权就是康奈尔大学的埃斯瓦尔·普拉萨德在其新著《美元陷阱》中要与读者分享的主题。他在书中指出，世界对美元存在着一种矛盾心态。人们原本希望2008年的金融危机能够消除这种货币在全世界的主宰地位。但令人不解的是，那场危机反而强化了美元的主宰，她的脆弱反倒成为了美元力量的来源。
在2008年的最后4个月中，美国吸引的资本净流入达到5000亿美元。美元是乱世的天堂，甚至就在造就乱世的是美国自己时也是如此。危机还“打破了”外汇储备应当保持在一个适当水平的“传统观点”，促使具有大量美元的新兴经济体储备了更多的美元。最后，美国的迅速衰落还迫使美联储戏剧性地放松了货币政策。作为回应，新兴经济体的央行买入美元以阻止自己的货币过快升值。
美联储的货币互换能够作为一种代价较低的替代方式以取代泛滥的储备累计吗？如果各国央行能在需求上升的时候从美联储获得美元，他们可能就不必在吝惜本国货币的供应了。因为，需求是明摆着的。印度，印度尼西亚，多尼米加和秘鲁都曾提出过这种请求。货币互换是一桩好买卖：美联储获得了外国央行将
货币放贷给银行的利息，即便是在外国央行要为此而承担信贷风险时也是如此。例如，美联储从与韩国进行的第一次货币互换中获得了6.84%的利息。但这不是美联储想参与其中的那种买卖。正如某官员所说：“我们不想推而广之。”
货币互换可能会有助于新兴经济体容忍美元的主宰。但是，这种主宰会长久吗？对此，普阿萨德持肯定的观点。他在书中写道，美元的地位“虽未达到最佳状态，但却是稳定和自我增强的”。也就是说，尽管这种特权非常不受待见，但美国还是能够胜任这份工作的。
美国不仅是世界上最大的经济体，还是最成熟的经济体之一。经济的规模和成熟程度不是能都同时达到的。在20世纪初的时候，英镑是全球储备货币，而且英国的金融体系也是覆盖面最广的。但是，当时的最大经济体却是美国。到2020年时，中国有可能会成为世界最大经济体，但未必会成为最发达的经济体。
美国的成熟反映在金融市场的深度上。在把由经济体产生的利润和收入变成可供交易的债权方面，该国有着常人不及的创造力。如果是在一个更加原始的体系中，这些战利品可能大都会被国家或者寡头所占有。但是，在美国，它们会以品种众多的金融资产的形式回馈给市场。
普拉萨德在书中，对中国与其被“广泛炒作的”可以取代美元的货币——元之间的关系进行了明显的对比。中国当前的GDP是美国的一半还多。但是，中国债务市场的规模只有美国的八分之一，允许外国人拥有的债务只其中的一小部分。该国中央政府的债务水平较低应当是其货币力量的一个来源。但是，中国可以提供的金融工具的总量是有限的。
美国有一个庞大但显不出强大的外部资产负债表。她在外国负债超过了海外资产。但是，这种令人担忧的事实却掩盖了一个可取之处：她的外国资产具有与众不同的冒险性和逐利性。另一方面，她的负债还具有流动性强，安全性高和收益率低的特点。因此，美国从其外国资产上的所得大于为外国负债付出的支出。
除了经济成熟度高之外，美国的人口也在趋于老龄化。一般认为，老龄化是经济趋弱的一个根源。但是，普拉萨德指出，老龄化或许是美元在全球受捧的另一个原因。在美国政府的债务中，领养老金的人持有一大块，而这一块是不由外国人所持有的。作为一个政治力量强大的选民群体，令养老金的人是不会允许政府通过通胀消化掉这些债权的。因此，美国强有力的领养老金群体充当了保护慷慨的外国债权人利益的角色。
最后，美国的成熟还有一层含义：美元不存在长期走强的趋势。这一点又同其主要的长期对手形成了对比。中国的经济仍然是一种追赶型的经济。随着她逐渐缩小与美国在生产力方面的差距，其按照通胀调整后的汇率也会趋向于上升。自2005年年中以来，人民币对美元已经升值了35%左右。
美元在那段时间内的贬值当然不利于持有美元资产的人。但是，美元的作用不仅仅在于保值。她已经成为一种广受欢迎的“融资型”货币。银行和跨国公司甚至在用其他货币累积资产时也会借入美元。由于没有人想借入一种只会升值的货币，因此，这个角色不是人民币可以轻松地扮演的了的。更为重要的是，由于其融资型货币的特点，美元往往在危机时走强。这解释了为什么新兴经济体会对美元的需求存在着“成批的”和“不可预测”的原因。美元或许不会保持住其相对于其他货币的价值。但是，在非常时期，美元资产的吸引力就在于她总能保持住相对于美元债务的价值。这种防御性也是美元成为全球霸主的一个原因。
Class in America 美国的阶层
Class in America美国的阶层
Mobility, measured社会流动性，固化的
America is no less socially mobile than it was a generation ago
固化的美国社会与三十年前相差无几
1 AMERICANS are deeply divided as to whether widening inequality is a problem, let alone what the government should do about it. Some are appalled that Bill Gates has so much money; others say good luck to him. But nearly everyone agrees that declining social mobility is a bad thing. Barac k Obama’s state-of-the-union speech on January 28th dwelt on how America’s ―ladders of opportunity‖ were failing. Paul Ryan and Marco Rubio, two leading Republicans, recently gave speeches decrying social immobility and demanding more effort to ensure poor people who work hard can better their lot.
2 Just as the two sides have found something to agree on, however, a new study suggests the conventional wisdom may be wrong. Despite huge increases in inequality, America may be no less mobile a society than it was 40 years ago.
3 The study, by a clutch of economists at Harvard University and the University of California, Berkeley, is far bigger than any previous effort to measure social mobility. The economists crunch numbers from over 40m tax returns of people born between 1971 and 1993 (with all identifying information removed). They focus on mobility between generations and use several ways to measure it, including the correlation of parents’ and children’s income, and the odds that a child born into the bottom fifth of the income distribution will climb all the way up to the top fifth.
4 They find that none of these measures has changed much (see chart). In 1971 a child from the poorest fifth had an 8.4% chance of making it to the top quintile. For a child born in 1986 the odds were 9%. The study confirms previous findings that America’s social mobility is low compared with many European countries. (In Denmark, a poor child has twice as much chance of making it to the top quintile as in America.) But it challenges several smaller recent studies that concluded that America had become less socially mobile.
5 This result has caused a huge stir, not least because it runs counter to public perceptions. A recent Gallup poll found that only 52% of Americans think there is plenty of opportunity for the average Joe to get ahead, down from 81% in 1998. It also jars with other circumstantial evidence. Several studies point to widening gaps between rich and poor in the kinds of factors you would expect to influence mobility, such as the quality of schools or parents’ investment of time and money in their children. Cross-country analyses also suggest there is an inverse relationship between income inequality and social mobility—a phenomenon that has become known as the ―Great Gatsby‖ curve.
6 What is going on? One possibility is that social stratification takes time to become entrenched. In a new book, Gregory Clark, an economic historian at the University of California, Davis, who tracks mobility over hundreds of years
by following surnames, reaches far more pessimistic conclusions. Another, sunnier, explanation is that even as income gaps have widened over the past 30 years, other barriers to mobility, such as discrimination against women and blacks, have fallen.
7 Most likely, the answer lies in the nature of America’s inequality, whose main characteristic is the soaring share of overall income going to the top 1% (from 10% in 1980 to 22% in 2012). The correlation between vast wealth accruing to a tiny elite and the ability of people to move between the rest of the rungs of the income ladder may be small—at least for now.
8 Whatever the explanation, it would be unwise to take much comfort from this study. For a start, since the gap between top and bottom has widened, the consequences of an accident of birth have become bigger. Second, if the gains of growth are going mostly to those at the top, that bodes ill for those whose skills are less in demand. Many economists worry that living standards for the non-elite will stagnate for a long time.
Is your town a launchpad or a swamp?
你的家乡是一架发射台还是一片沼泽？
9 Third, although social mobility has not changed much over time, it varies widely from place to place. In a second paper, the economists crunch their tax statistics by region. They find that the probability of a child born into the poorest fifth of the population in San Jose, California making it to the top is 12.9%, not much lower than in Denmark. In Charlotte, North Carolina it is 4.4%, far lower than anywhere else in the rich world.
10 This geographic prism also offers some pointers on what influences mobility. The economists found five factors that were correlated with differences in social mobility in different parts of America: residential segregation (whether by income or race); the quality of schooling; family structure (eg, how many children live with only one parent); ―social capital‖ (such as taking part in community groups); and inequality (particularly income gaps among those outside the top 1%). Social mobility is higher in integrated places with good schools, strong families, lots of community spirit and smaller income gaps within the broad middle class. Not a bad agenda for politicians to push, if only they knew how.
美国不平等逐渐扩大，严重分化，已经成为问题。美国政府也为此头痛不已。比尔?盖茨很有钱，有些人对此惊骇，有些人祝他好运。但社会愈发固化却是件坏事，对此几乎人人同意。1月28日，奥巴马发表了国情咨文演说，详细说明了美国―成功阶梯‖的渐衰（见文章）。近期，保罗?莱恩和马克罗?鲁比奥两位主要的共和党人发表演说，谴责了美国社会的固化，呼吁社会做出更多努力，保证那些进取的穷人能有一个较好的未来。
民主党和共和党在这个问题上达到了一致。然而，与此同时，一份新研究表明，传统思维可能有误。不平等差距在加剧，但当今的美国社会依然固化，与40年前相差无几。
此份新研究的作者是一群经济学家，来自哈佛大学和加州大学伯克利分校。为研究社会的流动性，研究付出了更大的努力，比以往任何一次都要大得多。他
们从四千多万张纳税申报单（去除了所有的识别信息）中得出数据，并对这些数据进行计算。这些申报单的主人都是在1971 年至1993年间出生。他们关注代际之间的流动性，使用多种方法进行测量，其中包括父母与子女收入的关联性。同时，那些处于收入分配底部第五层家庭的孩子，他们有可能一路直上，达到五分层的顶层。
他们发现，这些数据结果并未改变很多（见图表）。1971年，最贫穷家庭位于第五层的孩子有8.4%的机会成功，能到达顶层。1986年出生的孩子有9%的机会。研究证实了先前的发现结果：与多数欧洲国家（在丹麦，贫穷家庭的孩子获得成功到达顶层的机会是美国贫穷家庭孩子的两倍）相比，美国社会的流动性是低的。这就挑战了近期的一些小型研究，这些研究得出如此论断：美国社会已经变得更加固化。
新研究结果引起极大反响，不仅是因为研究结果与公众的观念背道而弛。近期，盖洛普民意测验发现，只有52%的美国人认为，普通人获得成功的机会有很多，低于1998年的81%。同时，研究结果也与其它证据不协调。多数研究显示，穷人和富人之间的差距正在扩大，以可以想象得到的方式影响着社会的流动性，比如受教育的质量、父母对子女时间金钱的投入。对多个国家的分析也表明，收入差距和社会流动性之间出现了一种相反的关系——这种现象已经为人所知，叫作―伟大的盖茨比‖曲线。
接下来如何？一种可能是，社会阶层要变得根深蒂固需要一定时间。格雷戈里?克拉克是加州大学戴维斯分校的经济历史学家。他通过研究姓氏的方法，对上百年的社会流动性进行了追踪。在一本新书中，他得出了非常悲观的结论（见文章）。还有一种解释比较乐观，认为即使过去三十年中，收入差距有所扩大，对流动性的其它障碍，比如对妇女和黑人的歧视，已经削减。
问题的答案极有可能根植于美国社会不平等的本质之中。美国社会不平等的主要特点就是，整体收入中，流入高层1%（1980年是10%，2012年为22%）人群的份额极速上升。一方面，巨大的财富流向少数精英人的手中。另一方面，有些人有能力在收入级梯之间流动。这两方面之间的关联性可能是小的——至少现在如此。
无论解释如何，无关痛痒地对待这份研究是不明智的。首先，因为顶层和底层之间的差距已经扩大，意外出生的后果会变得更大。第二，假如增长收益还是继续主要地流向顶层人群，那些掌握技能较少的人是凶多吉少的。多数经济学家担心，非精英人群的生活标准会在很长一段时间内不得提高。
第三，虽然社会流动性并未随着时间改变很多，但不同地域还是不同。在第二份研究中，经济学家按照地域对赋税统计数据。他们发现，在加州圣何塞人口中，位于最贫穷家庭第五层的孩子获得成功、达到顶层的概率为12.9%，并不比丹麦的低出很多。在北卡罗莱纳的夏洛特市，这个概率为 4.4%，远远低于富裕国家中的其它任何一个区域。这种由区域因素产生的“棱镜”也给人们提供了一些线索，知道了影响社会流动性的因素。经济学家发现了五点，这些因素与美国不同地区社会流动性的差别有关：居住隔离（收入或种族因素造成）；教育质量；家庭结构（比如，与单亲父母同住的子女数量）；“社会资本”（比如参加社区组团）以及不平等因素（尤其是高层1%以外人群的收入差距）。有些地区非常协调，教育优质，家族坚固，集体精神强大，广大中产阶级中收入差距较小。这些地区的社会流动性会更高。对于政府工作人员来说，把这些纳入工作日程加以实施不算是坏主意，假如他们知道如何实施就更好了。
社会流动性（Social Mobility）实际上是一个社会学术语，包含两个意思，一是指民众在地域上的迁徙情况，因此，也称之为水平流动性，另一层的意思是指人们在社会阶层结构上的升迁，是指纵向的流动性。按照学究式的定义，社会流动性是指个人或群体由社会的某一阶层到另一阶层的活动。例如，直白点的意思是，即一个人由打工者爬升到具有名望、权利及财富的社会位置。而进一步严格区分，社会流动性又分为代内流动（Intra-generational mobility）和代间流动
（Inter-generational mobility），前者是指个人在自己一身中的社会地位的变迁，例如，从一个蓝领阶层成为白领阶层，而后者是指下一代相对于父母社会地位的变迁，像奥巴马从一个普通的黑人移民的后代成为美国的总统。而对于一个开放的社会来讲，对于不同阶层的人来讲，都应具有大致较为公平的机会，都鼓励社会成员通过努力和竞争改变自己的命运。而与此相反，对封闭的社会体系而言，底层向上爬的机会甚少，个人的命运难以改变。封闭的社会体系的弊端显而易见，会导致各个社会阶层的仇视、腐败的滋生、社会的不稳定和创新精神的减少。
Metaphysicians玄学家
Combating bad science打击坏科学
Metaphysicians形而上学家
Sloppy researchers beware. A new institute has you in its sights
粗心大意的研究者们注意了！你正被一种新的机构所关注。
1 ―WHY most published research findings are false‖ is not, as the title of an academic paper, likely to win friends in the ivory tower. But it has certainly influenced people (including journalists at The Economist). The paper it introduced was published in 2005 by John Ioannidis, an epidemiologist who was then at the University of Ioannina, in Greece, and is now at Stanford. It exposed the ways, most notably the overinterpreting of statistical significance in studies with small sample sizes, that scientific findings can end up being irreproducible—or, as a layman might put it, wrong.
2 Dr Ioannidis has been waging war on sloppy science ever since, helping to develop a discipline called meta-research (ie, research about research). Later this month that battle will be institutionalised, with the launch of the
Meta-Research Innovation Centre at Stanford.
3 METRICS, as the new laboratory is to be known for short, will connect enthusiasts of the nascent field in such corners of academia as medicine, statistics and epidemiology, with the aim of solidifying the young discipline. Dr Ioannidis and the lab’s co-founder, Steven Goodman, will (for this is, after all, science) organise conferences at which acolytes can meet in the world of atoms, rather than just online. They will create a ―journal watch‖ to monitor scientific publishers’ work and to shame laggards into better behaviour. And they will spread the message to policymakers, governments and other interested parties, in an effort to stop them making decisions on the basis of flaky studies. All this in the name of the centre’s nerdishly valiant mission statement: ―Identifying and minimisi ng persistent threats to medical-research
quality.‖
The METRICS systemMETRICS系统
4 Irreproducibility is one such threat—so much so that there is an (admittedly tongue-in-cheek) publication called theJournal of Irreproducible Results. Some fields are making progress, though. In psychology, the Many Labs Replication Project, supported by the Centre for Open Science, an institute of the University of Virginia, has re-run 13 experiments about widely accepted theories. Only ten were validated. The centre has also launched what it calls the Cancer Biology Reproducibility Project, to look at 50 recent oncology studies.
5 Until now, however, according to Dr Ioannidis, no one has tried to find out whether such attempts at revalidation have actually had any impact on the credibility of research. METRICS will try to do this, and will make recommendations about how future work might be improved and better
co-ordinated—for the study of reproducibility should, like any branch of science, be based on evidence of what works and what does not.
6 Wasted effort is another scourge of science that the lab will look into. A recent series of articles in the Lancet noted that, in 2010, about $200 billion (an astonishing 85% of the world’s spending on medical research) was squandered on studies that were flawed in their design, redundant, never published or poorly reported. METRICS will support efforts to tackle this extraordinary inefficiency, and will itself update research about the extent to which randomised-controlled trials acknowledge the existence of previous investigations of the same subject. If the situation has not improved, METRICS and its collaborators will try to design new publishing practices that discourage bad behaviour among scientists.
7 There is also Dr Ioannidis’s pet offender: publication bias. Not all studies that are conducted get published, and the ones which do tend to be those that have significant results. That leaves a skewed impression of the evidence.
8 Researchers have been studying publication bias for years, using various statistical tests. Again, though, there has been little reflection on these methods and their comparative effectiveness. They may, according to Dr Ioannidis, be giving both false negatives and false positives about whether or not publication bias exists in a particular body of studies.
9 Dr Ioannidis plans to run tests on the methods of meta-research itself, to make sure he and his colleagues do not fall foul of the very criticisms they make of others. ―I don’t want‖, he says, ―to take f or granted any type of
meta-research is ideal and efficient and nice. I don’t want to promise that we can change the world, although this is probably what everybody has to promise to get funded nowadays.‖
作为一篇学术文章，如果拥有这样一个标题--“为什么大多数研究发现都是假的？”，是无法在科学研究这个象牙塔里获得认可的。但是，它确实对人们产生了影响（包括本报记者在内）。这篇文章是由约翰-约阿尼迪斯于2005年发表
的，当时他是希腊约阿尼纳大学的流行病学家，现在任职于斯坦福大学。它揭露了科学发现有时最终无法重现的原因，或者，就像外行人说的那样，是错的，尤其以过分诠释小样本事件之统计意义现象突出。
一直以来，约阿尼迪斯博士就站在马虎科学研究的对立面，帮助开发了一种新的学科，称之为元研究（即对研究进行研究）。随着本月晚些时候斯坦福大学的元研究创新中心的成立，这种没有硝烟的战争将制度化。
人们把这个实验室称之为“METRICS”—会把研究一些学科比如医学，统计学和流行病学等被忽视方面，这个新领域的爱好者聚集起来，目的就是为了让这个新生的学科稳定地发展下去。约阿尼迪斯博士和这个实验室的另一名创建者，史蒂文-古德曼将会召开一些会议（毕竟，这也是科学），以此让追随者们不仅仅在网上相互联系，而且还能在原子的世界里互相交流。他们将会创建一个“观察日记”，用来监控科学出版者的工作及以更适合的方式让那些做事拖拉的人感学到羞愧。他们还会把信息反馈给决策者们，政府和其它有关方面，希望能够让这些人不要为了一些古怪研究做出什么决策。所有这些都反应了这个中心有些让人讨厌，但却勇敢的使命陈述，“识别出，并尽量减少那些对医疗研究质量的持续性威胁。”
不可再现性就是这样一种威胁—这种威胁的程度之大，以至于现在有一个称为“不可重现杂志”的出版物（当然这暗含着嘲讽意味）。但是，有些领域取得些进展了。在心理学领域，许多实验室项目的复制—得到了弗吉尼亚大学开放科学中心的支持—已经重现了13项被广泛接受理论的实验。只有10项进行了验证。这个中心也发起了称之为癌症生物学重复性项目的研究，旨在对最近的50项肿瘤研究进行研究。
然而，根据约阿尼迪斯博士的研究，直到现在还是没有人试图去发现，类似这些重新验证的企图是不是真的对研究的可信程度有影响。METRICS将会在这方面进行尝试，而且会就基于现在的研究和不可行的基础上，对如何在未来进行提高，如何更好地调节—这是可重复性应该研究的方向，就像其它科学机构一样，做出一些建议.
无用功会是这个实验室监控的另一个科学危害。柳叶刀最近的一系列文章指出了，在2010年，约有二千亿美元（在世界医学研究的开支就达到了让人惊讶的85%）被浪费在了那些设计有缺陷，多余的，而且从未发表或者报道甚少的研究上。METRICS会努力支持解决这个异常的效率低下，并且会及时更新它自身的研究进展—即以随机对照试验来确认同一项目以前调查的证据。如果这个情况还没有改善，METRICS和它合作者会尝试设计新的出版方式，以抑制科学之间的不良行为。还有一个约阿尼迪斯博士不能容忍的：出版偏倚。不是所有进行的实验都能出版。那些希望可以出版的往往就是些研究取得显著成果的。这让那些成果往往被人误解。
多年以来，研究者们一直通过不同的统计试验研究出版偏倚。但是，他们的研究方式和相对有效性几乎没什么实质性的结果。约阿尼迪斯博士表示，在研究特例是否存在出版偏倚现象时，这些研究可能同时给出了错误否定和错误肯定的结论。
约阿尼迪斯博士计划对元研究本身的方式进行测试，以确定他和他的同事们没有做出与他们批评别人错误做法相同的行为。他表示，“我不会想当然地认为，元研究是一种理想的，有效的和完美的研究。我不想承诺我们可以改变世界—尽管这是现在每个研究者希望取得资金帮助的理由。”
Obamacare 奥巴马医改
U phill all the way长路漫漫
As the deadline for signing up nears, Obamacare looks precarious
随着报名截止日期临近，奥巴马医改似乎充满了不确定性
Mar 29th 2014 | PHILADELPHIA | From the print edition
BARACK OBAMA signed the Affordable Care Act on March 23rd, 2010. Exactly four years later J. Louis Felton, a pastor in Philadelphia, led his flock in an unusual procession: out of church and onto a sales bus owned by a local insurer. ―We need to sign up,‖ Mr Felton says. ―People in our communities have never had the opportunity to get health coverage before.‖ On t he bus he prayed for Obamacare’s success.
It could use some help. The fight over the law makes mud-wrestling look decorous. This year Obamacare is, yet again, Republicans’ favourite weapon on the campaign trail. On March 25th it was, yet again, debated in the Supreme Court (see article). Meanwhile, Mr Obama continues to undermine his own law by delaying parts of it: this month officials said Americans could keep old plans that don’t comply with Obamacare for another two years. America is the world’s only ri ch country not to have universal health care. Obamacare was meant to address that. In the past insurers charged the sick higher rates than the healthy. Since January this has been banned. To keep insurers from going bust, the law requires all Americans to have insurance or pay a fine. The premiums from cheap, healthy people are supposed to offset the costs of the sick. New online health exchanges allow people to shop for coverage. For the hard-up, Obamacare does two things. It expands Medicaid (public health care for the poor) to individuals earning up to about $16,000. And it offers subsidies to those who make more than $11,700 but less than $46,700.
In 2011 the Congressional Budget Office (CBO) projected that Obamacare would lower the number of uninsured by 21m in 2014 and 34m in 2021. Now the CBO is gloomier: it says the law will shrink the ranks of the uninsured by 13m in 2014 and 25m in 2021. More than 30m Americans will still lack coverage after Obamacare is fully implemented.
The gap that makes no sense
毫无意义的差距
The law’s drafters assumed that the states would all expand Medicaid, so the subsidies only kick in above that $11,700 threshold. But after the Supreme Court said the states could refuse to expand Medicaid, half of them (mostly Republican-led) did just that. In those states, millions of people will not qualify for Medicaid but are too poor to qualify for Obamacare subsidies.
The results are perverse. In Pennsylvania, which has not expanded Medicaid, childless adults are ineligible, no matter how poor. Paul Johnson, a 51-year-old repairman, boarded that bus in Philadelphia on March 24th, hoping to find coverage. ―I’ve never had a check-up,‖ he said. He will have to wait a bit longer. Earning less than $10,000 a year, Mr Johnson is too poor to qualify for an Obamacare subsidy. But he does not qualify for Medicaid, either. He left the
bus as he had entered it, without insurance, hoping not to fall ill. Pennsylvania and 33 other states also declined to create their own insurance exchanges. The federal government did so on their behalf, setting a new record for bureaucratic ineptitude. The launch of https://www.360docs.net/doc/847558554.html, in October went so badly that the CBO cut its estimate for the number of enrollees this year from 7m to 6m.
The website is working better now. The deadline for individuals to have coverage in 2014 or pay a penalty was supposed to be March 31st. Under new rules, many who claim to have begun the process will have more time to sign up. By mid-March more than 5m Americans had done so. Mr Obama and his allies hope enrolment will jump by April, especially among the young and healthy. People aged 18-34 were a quarter of those who had enrolled by the end of February, though they are 40% of those eligible to sign up.
The worry is that too few healthy people will enroll, prompting insurers to raise prices next year. That would make fit folk even less likely to buy coverage. To avoid this ―death spiral‖, the health department spent $52m on adverts from January through March. Mr Obama has hawked the law to young Americans at meetings, online and on television chat shows.
He has also tweaked his reform in ways that may appease angry voters in the short run, but make it less likely to work in the long run. For example, he has made it easier to dodge the requirement to buy insurance, by adding to the law’s long list of exemptions for ―hardship‖. The weaker the mandate, the less likely healthy people are to sign up: they know they can wait until they fall sick to buy insurance. Paul Starr of Princeton University has argued that the mandate should be made stronger: refuseniks should have to opt out on their tax returns, and should not then be allowed to buy an Obamacare policy for five years.
Mr Obama has also done things likely to make insurance more expensive. For example, his health department will require insurers to cover a broader network of doctors in 2015. That will raise prices—this year, plans with a wide network were 26% more expensive than plans with a narrow one, according to McKinsey, a consultancy. Higher prices will deter enrolment.
A death spiral is unlikely, but by March only 15% of those who could enroll through the exchanges had actually done so, according to the Kaiser Family Foundation, a think-tank. According to a new Kaiser survey, six in ten were still unaware of the enrolment deadline.
Just 19% of Americans said the law has helped them. More continue to oppose Obamacare than support it, though only three in ten favour scrapping it. So long as power in Washington is divided and the parties are polarised, the law can neither be amended nor repealed. It is up to Mr Obama to fix it using his administrative powers; he does not have much time.
巴拉克奥巴马在2010年3月23日签署了评价医疗法案，在四年后的同一天，宾夕法尼亚的一位牧师J.路易斯菲尔顿（J.Louis Felton）带领其信众进行了一次不同寻常的游行：在教堂外举行也在当地保险公司的销售大巴上举行。“我们需
要报名，”菲尔顿先生说。“我们社区的人以前从没有过享受健康保险的机会。”他在大巴上祈祷奥巴马医改获得成功。
这可能会有些帮助。关于这项法案的斗争之激烈让泥巴摔跤运动都显得得体了。今年奥巴马医改再次成为共和党人竞选游说过程中最喜欢的武器。3月25日，再一次在最高法院中讨论这项法案。与此同时，奥巴马通过延迟实行法案中某些部分，不断弱化他自己的这项法案：本月官员表示美国人可以继续使用不遵从奥巴马医改的旧保险方案的时间再延长两年。
美国是世界上唯一一个没有统一医疗保险的发达国家。奥巴马医改就是为了解决这一问题。过去保险公司对病人征收的费用要高于对健康人征收的费用。一月以来这种做法被禁止。为避免保险公司破产，法律要求所有的美国人必须持有保险否则要交罚款。对小气的健康人士征收的保险费理应抵消掉不健康人士的花费。新型在线保健交换系统允许人们可以购买保险。对于手头拮据的人，奥巴马医改做出了两点改变。将医疗补助计划（是针对穷人的医疗保险）的范围扩展至最高收入约为16,000美元的人。并且给那些收入在11,700—46,700美元间的人提供补助金。
2011年美国国会预算办公室估计奥巴马医改将使没有保险的公民人数2014年时减少2100万，2021年时减少3400万。但是现在国会预算委员会的估计就没有这么乐观了：它表示这项法案将使没有保险的公民人数2014年时减少1300万人，2021年时减少2500万人。奥巴马医改完全实行后，超过3000万美国人将仍旧没有保险。
这项法案的起草者想当然地认为医疗补助计划会覆盖全联邦，这样一来补助金只在超过11,700美元的临界值时有效。但在最高法院声明各州可以拒绝使用医疗补助法案之后，一半数量的州政府（大多是共和党领导的）就拒绝使用这项法案。在这些州中，成百上千万的人没有使用医疗补助计划的资格，但同时因为收入太低也没有享受奥巴马医改补助金的资格。
这种结果是不通情理的。宾夕法尼亚州没有实行医疗补助计划，没有孩子的成年人无论收入何其少，都没有资格享受奥巴马医改补助金。保罗约翰逊是一个51岁的修理工，在3月24日登上了那辆宣传巴士希望能有份保险。“我从来没体检过，”他说。他将不得不再等些时间。由于年均收入少于1万美元，约翰逊先生没有享受奥巴马医改补助金的资格，但是他也没有享受医疗补助计划的资格。他登上了那辆巴士随即又下来了，因为没有他的保险，他希望不要生病。
宾夕法尼亚州以及其它33个州也拒绝创立自己的保险交易所。联邦政府代表他们做了这件事情，这简直是创立了官僚无能的新纪录。十月份发起的官方医疗网站运行很差，以至于国会预算办公室对今年申请者的人数估计值从700万降低到600万。
现在网站运行状况好多了。2014年个人申请保险的或支付罚款的截止日期本来是3月31日。根据新规定，那些声称开始这一程序的人会有更多的时间进行报名。截至3月中旬，超过500万美国人报名了。奥巴马及其同僚希望四月份报名人数会增加，特别是那些健康的年轻人。年龄在18到34之间的人占二月低之前报名者总数的四分之一，虽然这些人占有资格报名人的总数的40%。
有人担心很少有健康的人会报名，这会致使保险公司明年会提高价格。这就更不可能会让那些健康的人买保险。为避免这种“死亡漩涡”，1月到3月期间卫生部门在广告上投入了5200万美元。奥巴马也在各种会议上、网络上以及电视脱口秀上向美国的年轻人兜售这项法案。
奥巴马对他的改革进行了修改，短期内可能会抚恤那些愤怒的投票者，但是长期内很难奏效。比如，他通过向法案中添加“困苦”豁免长单使得规避保险的购买需求变得更加容易。强制性月若，健康人报名的可能性就越小：因为他们知道他们可以再生病的时候再买保险。普林斯顿大学的保罗斯塔尔称应该嘉庆强制性：那些拒绝者应该退出纳税申报，五年内不允许购买奥巴马医改保险。
奥巴马采取的行动很可能会使保险价格更高。比如，其卫生部门要求保险公司在2015年建立一个覆盖面更广的医生网络。这就会提高保险价格——根据麦肯锡咨询公司，今年覆盖面更广的保险计划的费用比起覆盖面小的要高出26%。高额费用会让报名者望而却步。
出现死亡漩涡的几率很小，但是根据智库凯撒家庭基金会的统计，截至三月，有资格通过交易平台报名的人中只有15%真正报了名。其一项新调查显示还有60%的人不知道报名截至日期。
仅仅有19%的美国人表示这项法案对其有帮助，更多的是继续反对这项法案而非支持，虽然只有30%的人支持废除这项法案。只要华盛顿继续实行三权分立、两党继续对立，那么这项法案既不会被修改也不会被废除。法案的修改取决于奥巴马使用其行政权力；但是他没有太多时间。
Who pressed the pause button? 谁按了暂停键？
Global warming全球变暖
Who pressed the pause button?谁按了暂停键？
The slowdown in rising temperatures over the past 15 years goes from being unexplained to overexplained
过去十五年气温升高减缓或没有解释，或过度解读
BETWEEN 1998 and 2013, the Earth’s surface temperature rose at a rate of 0.04°C a decade, far slower than the 0.18°C increase in the 1990s. Meanwhile, emissions of carbon dioxide (which would be expected to push temperatures up) rose uninterruptedly. This pause in warming has raised doubts in the public mind about climate change. A few sceptics say flatly that global warming has stopped. Others argue that scientists’ understanding of the climate is so flawed that their judgments about it cannot be accepted with any confidence. A convincing explanation of the pause therefore matters both to a proper understanding of the climate and to the credibility of climate science—and papers published over the past few weeks do their best to provide one. Indeed, they do almost too good a job. If all were correct, the pause would now be explained twice over.
This is the opposite of what happened at first. As evidence piled up that temperatures were not rising much, some scientists dismissed it as a blip. The temperature, they pointed out, had fallen for much longer periods twice in the past century or so, in 1880-1910 and again in 1945-75 (see chart), even though the general trend was up. Variability is part of the climate system and a 15-year hiatus, they suggested, was not worth getting excited about.
An alternative way of looking at the pause’s significance was to say that there had been a slowdown but not a big one. Most records, including one of the best known (kept by Britain’s Meteorological Office), do not include
measurements from the Arctic, which has been warming faster than anywhere else in the world. Using satellite data to fill in the missing Arctic numbers, Kevin Cowtan of the University of York, in Britain, and Robert Way of the University of Ottawa, in Canada, put the overall rate of global warming at 0.12°C a decade between 1998 and 2012—not far from the 1990s rate. A study by NASA puts the ―Arctic effect‖ over the same period somewhat lower, at 0.07°C a decade, but that is still not negligible.
It is also worth remembering that average warming is not the only measure of climate change. According to a study just published by Sonia Seneviratne of the Institute for Atmospheric and Climate Science, in Zurich, the number of hot days, the number of extremely hot days and the length of warm periods all increased during the pause (1998-2012). A more stable average temperature hides wider extremes.
Still, attempts to explain away that stable average have not been convincing, partly because of the conflict between flat temperatures and rising CO2 emissions, and partly because observed temperatures are now falling outside the range climate models predict. The models embody the state of climate knowledge. If they are wrong, the knowledge is probably faulty, too. Hence attempts to explain the pause.
Chilling news寒冷的新闻
In September 2013 the Intergovernmental Panel on Climate Change did so in terms of fluctuating solar output, atmospheric pollution and volcanoes. All three, it thought, were unusually influential.
The sun’s power output fluctuates slight ly over a cycle that lasts about 11 years. The current cycle seems to have gone on longer than normal and may have started from a lower base, so for the past decade less heat has been reaching Earth than usual. Pollution throws aerosols (particles such as soot, and suspended droplets of things like sulphuric acid) into the air, where they reflect sunlight back into space. The more there are, the greater their cooling effect—and pollution from Chinese coal-fired power plants, in particular, has been rising. Volcanoes do the same thing, so increased volcanic activity tends to reduce temperatures.
Gavin Schmidt and two colleagues at NASA’s Goddard Institute quantify the effects of these trends in Nature Geoscience. They argue that climate models underplay the delayed and subdued solar cycle. They think the models do not fully account for the effects of pollution (specifically, nitrate pollution and indirect effects like interactions between aerosols and clouds). And they claim that the impact of volcanic activity since 2000 has been greater than previously thought. Adjusting for all this, they find that the difference between actual temperature readings and computer-generated ones largely disappears. The implication is that the solar cycle and aerosols explain much of the pause. There is, however, another type of explanation. Much of the incoming heat is absorbed by oceans, especially the largest, the Pacific. Several new studies link the pause with changes in the Pacific and in the trade winds that influence
the circulation of water within it.
Trade winds blow east-west at tropical latitudes. In so doing they push warm surface water towards Asia and draw cooler, deep water to the surface in the central and eastern Pacific, which chills the atmosphere. Water movement at the surface also speeds up a giant churn in the ocean. This pulls some warm water downwards, sequestering heat at greater depth. In a study published in Nature in 2013, Yu Kosaka and Shang-Ping Xie of the Scripps Institution of Oceanography, in San Diego, argued that much of the difference between climate models and actual temperatures could be accounted for by cooling in the eastern Pacific.
Every few years, as Dr Kosaka and Dr Xie observe, the trade winds slacken and the warm water in the western Pacific sloshes back to replace the cool surface layer of the central and eastern parts of the ocean. This weather pattern is called El Ni?o and it warms the whole atmosphere. There was an exceptionally strong Ni?o in 1997-98, an unusually hot year. The opposite pattern, with cooler temperatures and stronger trade winds, is called La Ni?a. The 1997-98 Ni?o was followed by a series of Ni?as, explaining part of the pause.
Switches between El Ni?o and La Ni?a are frequent. But there is also a
long-term cycle called the Pacific Decadal Oscillation (PDO), which switches from a warm (or positive) phase to a cool (negative) one every 20 or 30 years. The positive phase encourages more frequent, powerful Ni?os. According to Kevin Trenberth and John Fasullo of America’s National Centre for Atmospheric Research, the PDO was positive in 1976-98—a period of rising temperatures—and negative in 1943-76 and since 2000, producing a series of cooling Ni?as.
But that is not the end of it. Laid on top of these cyclical patterns is what looks like a one-off increase in the strength of trade winds during the past 20 years. According to a study in Nature Climate Change, by Matthew England of the University of New South Wales and others, record trade winds have produced a sort of super-Ni?a. On average, sea levels have risen by about 3mm a year in the past 30 years. But those in the eastern Pacific have barely budged, whereas those near the Philippines have risen by 20cm since the late 1990s. A wall of warm water, in other words, is being held in place by powerful winds, with cool water rising behind it. According to Dr England, the effect of the trade winds explains most of the temperature pause.
If so, the pause has gone from being not explained to explained twice over—once by aerosols and the solar cycle, and again by ocean winds and currents. These two accounts are not contradictory. The processes at work are understood, but their relative contributions are not.
Nor is the answer to what is, from the human point of view, the biggest question of all, namely what these explanations imply about how long the pause might continue. On the face of it, if some heat is being sucked into the deep ocean, the process could simply carry on: the ocean has a huge capacity
to absorb heat as long as the pump sending it to the bottom remains in working order. But that is not all there is to it. Gravity wants the western-Pacific water wall to slosh back; it is held in place only by exceptionally strong trade winds. If those winds slacken, temperatures will start to rise again.
The solar cycle is already turning. And aerosol cooling is likely to be reined in by China’s anti-pollution laws. Most of the circumstances that have put the planet’s temperature rise on ―pause‖ look temporary. Like the Terminator, global warming will be back.
从1998年到2013年，地球表面的温度以每十年0.04℃的速率升高，远低于九十年代的0.18摄氏度。同时二氧化碳排放（预计会提升温度的）不间断的上升。变暖暂停了，公众心中对气候变化产生了疑问。一些怀疑论者直截了当的说全球变暖停止了。另一些人说，科学家们对气候的理解有误，他们关于气候的判断不能够自信地接受。因此一个对此暂停令人信服的解释对关于气候的合理的理解和气候科学的公信力都很重要—最近几周发表的论文尽力的提供一个解释。的确，他们基本上完成得很好。如果他们都是正确的，暂停可以得到强力的解释。
这和最初所发生的的事情完全相反。当证据开始聚集，显示温度没有升高太多，某些科学家把此当成暂时现象不予考虑。他们指出，在过去的大约一个世纪里，温度下降了两次，时间更长，从1880到1910然后再一次从1945到1975（看图表），即使如此，大趋势还是上升的。变化是气候系统的一部分，而且，他们说，15年的间隙并不值得激动。
看待这个暂停的另一个方法是说减缓了但是规模不大。绝大多数的记录，包括一个最出名的（由英国气象办公室保管），并没有来自北极的测量，北极比世界上其他地方都要快。来自英国约克大学的凯文?高碳（Kevin Cowtan）和加拿大渥太华大学罗伯特?魏（Robert Way）使用了卫星数据来弥补确实的北极数据，把1998年到2012年的全球变暖总体速度定为0.12℃—和90年代的速度差别不大。美国国家航空航天局（NASA）把同一时期的―北极效应‖定的略低，在十年中0.07℃，但是这也不是可以忽视的。
同样值得记住的是，平均变暖并不是气候变化的唯一标准。根据苏黎世的大气和气候科学机构（Institute for Atmospheric and Climate Science）的索尼娅?斯尼维纳（Sonia Seneviratne）刚刚发表一篇研究，在暂停期间（1998到2012），热天的天数，极端热天的天数和暖天气的持续时间都增加了。更稳定的平均气温掩盖了更多的极端气候。
把稳定的平均数解释过去的尝试仍然不能令人信服，部分原因是平直的温度和上升的二氧化碳排放之间的矛盾，部分原因是观测到的温度现在降至气候模型预测的范围之外。如果它们错了，这些知识也许也是错的。所以要尝试解释此暂停。
2013年9月，政府间气候变化专家委员会（Intergovernmental Panel on Climate Change）在太阳能输出、大气污染和火山活动方面解释它。委员会认为全部这三个原因都通常是有影响的。
太阳的能量输出以一个11年的周期略微波动。目前的周期貌似比正常要长，可能从一个较低的水平开始，所以在上一个十年到地球的能量比通常情况少。污染把浮质（颗粒，如煤灰，悬浮的微滴状物，像硫酸）抛入大气，它们在此处把阳光反射会太空。它们越多，它们的冷却效应就越大—特别是中国的煤火电站的