Since the financial crisis, the global economy has travelled at two speeds. Developing countries have steamed ahead, powered by China’s voracious appetite for raw materials. Meanwhile, the west has limped along, as households and states cut back spending to address towering debts.

In the past 12 months, however, this picture has shifted. Just as confidence has returned to parts of the rich world, plummeting commodity prices have exposed the frailties of emerging markets. In October, the International Monetary Fund slashed its forecasts for the likes of Indonesia and Brazil. The fund now believes that the bulk of positive news for 2014 will come from high-income countries.

The US economy, in particular, offers grounds for optimism. The housing market has strengthened, after the massive injection of liquidity by the US Federal Reserve helped to lower mortgage rates. The labour market is becoming more buoyant and cheerier consumers have resumed spending. For now, investment is still lagging behind. But were corporations to use the large cash piles upon which they are sitting to finance new projects, the US economy could easily edge closer to its pre-crisis trend. Britain is also motoring, thanks to a sudden jump in consumption. However, banks are still lending too little to business, in spite of ultra-low interest rates.

In east Asia, Japan is emerging from 15 years of deflation, aided by the mammoth monetary stimulus unleashed by its central bank. But for “Abenomics” to succeed, it is essential that the government follows up swiftly with its programme of structural reforms, aimed at lifting long run growth.

The eurozone is still the worst performer in the rich world. Unemployment remains dangerously high and activity continues to disappoint, particularly in France and Italy. But Spain and Ireland, two of the countries worst hit by the crisis, are picking up. They have a mountain of debt to repay, but at least they have stopped shrinking. The challenge for the currency bloc is to put its banking system on a safe footing. The forthcoming asset quality review by the European Central Bank will be a make-or-break moment. Governments must accept that the exercise needs to be rigorous if Europe is to accelerate again.

The single biggest risk for high-income countries comes from the Fed. A fortnight ago, during his valedictory press conference, chairman Ben Bernanke announced that the central bank would reduce its asset purchases from $85bn to $75bn a month. Markets were not too bothered, as the Fed also promised it would keep rates low for longer than previously thought. But this message may become less credible if “tapering” gathers speed in 2014. This will put upward pressure on market rates on both sides of the Atlantic.

The US should be strong enough to withstand the shock. In the eurozone, the European Central Bank may have to deploy more unconventional weapons, for example launching a new round of cheap funding for banks. Conversely, tapering raises risks for emerging markets. As domestic bonds become attractive again, western investors will repatriate the funds parked in more exotic locations. Countries with large current account deficits could run into trouble. Note Turkey, where political the crisis this month has already sent stocks plunging.

The outlook for the developing world largely hinges on what happens in China. The authorities are adamant that they can keep output growth above 7 per cent. But Beijing also wants to rein in credit creation. Striking this balance will be hard and could lead to a sudden deceleration. That would add to the misery of commodity producers – and transform an uncertain year into a difficult one.

自此次金融危机以来，全球经济一直以两个速度运行。发展中国家因中国对原材料的旺盛需求而全速前进。同时，西方则因不断攀升的债务带来的家庭和政府支出削减蹒跚而行。

然而，过去12个月，情况发生了变化。信心回归部分富裕国家，而大宗商品价格日益下挫则暴露出新兴市场的脆弱。今年10月，国际货币基金组织(IMF)下调了其对印尼和巴西等国的增长预期。IMF现在认为，2014年多数乐观消息将来自高收入国家。

尤其是，美国经济提供了乐观的理由。美国房地产市场一直走强，此前美联储(Fed)的大规模注资帮助降低了抵押贷款利率。劳动力市场正变得更为活跃，消费者更为愉悦消费也随之重启。目前，投资仍然滞后。但如果企业要利用其坐拥的巨额现金为新项目融资的话，美国经济增长可能会很容易接近危机前水平。由于消费突然飙升，英国经济引擎也在启动。然而，尽管利率处于超低位，银行贷给企业的贷款仍太少。

在东亚，日本正从长达15年的通缩中复苏，这得益于日本央行(BoJ)推出的大规模货币刺激计划。但“安倍经济学”(Abenomics)若想成功，日本政府必须快速落实旨在促进日本经济长期增长的结构性改革计划。

欧元区仍是富裕世界中表现最差的地区。失业率仍处于危险高位，经济活动继续疲弱，尤其是在法国和意大利。但受此次危机影响最严重的两个国家——西班牙和爱尔兰正在复苏。它们的待偿债务水平很高，但其经济至少停止了萎缩。欧元区面临的挑战在于，将该地区银行业体系置于安全框架之内。欧洲央行(ECB)即将发布的资产质量评估将是决定成败。各国政府必须承认，如果欧洲经济若想再次提速，需要严格执行此次评估。

高收入国家面临的最大单一危险来自美联储(Fed)。两周前，在卸任前最后一次新闻发布会上，美联储主席本?伯南克(Ben Bernanke)宣布，美联储将把每月资产购买规模从850亿美元降至750亿美元。市场没有表现出过于不安，因为美联储还承诺，其维持低利率的时间将超出人们以前的预期。但如果“缩减”在2014年加速，此承诺可能会变得不太可信。这将对欧美市场利率构成上行压力。

美国的实力应足以顶住这种冲击。但在欧元区，欧洲央行可能不得不动用更多非常规武器，例如为银行提供新一轮廉价融资。相反，“缩减”给新兴市场带来了风险。随着国内债券重现吸引力，西方投资者将把存放在海外的资金汇回国内。背负高额经常账户赤字的国家可能会陷入困境。要关注土耳其，该国本月的政治危机已导致股市遭受重挫。

发展中国家的前景主要取决于中国的表现。中国政府坚定地认为，他们能够将经济增速保持在7%以上。但中国政府也希望控制信贷发行。实现这种平衡很难，而且可能会导致经济突然减速。这将加剧大宗商品生产国的痛苦，同时将一个不确定之年变成一个艰难之年。