February has been the month for revisiting old and unpleasant economic concepts. Last week, financial markets experienced that 1970s feeling, as a combination of rising inflation and unemployment in the US triggered unwelcome memories of the decade of stagflation that ended the postwar golden age and the Keynesian consensus. Then came this week's report that the United Nations' world food programme might have to ration food aid. Set against a backdrop of rising food prices worldwide – global food prices have now risen by more than 75 per cent since their lows of 2000, jumping more than 20 per cent in 2007 alone – the news revived fears from a much earlier era, conjuring up the Reverend Thomas Malthus. 

    今年2月成了反思那些令人不快的古老經(jīng)濟(jì)概念的一個(gè)月。上周，金融市場(chǎng)體驗(yàn)了上世紀(jì)70年代時(shí)的感受，美國(guó)通脹率與失業(yè)率的雙重上升，喚起了人們對(duì)那個(gè)時(shí)代的糟糕回憶：十年滯脹，讓?xiě)?zhàn)后的黃金歲月和凱恩斯共識(shí)就此終結(jié)。然后，本周又有報(bào)道稱，聯(lián)合國(guó)世界糧食計(jì)劃署(UN World Food Programme)可能不得不對(duì)糧食援助實(shí)行配額制。在全球食品價(jià)格不斷上漲的背景下（全球食品價(jià)格已較2000年的低位上漲75%以上，僅2007年一年的升幅就超過(guò)20%），這則消息喚醒了人們?cè)缒甑目謶郑�召回了托馬斯•馬爾薩斯牧師(Reverend Thomas Malthus)的幽靈。

    Soaring food prices have also revived some more contemporary worries. When China's annual inflation rate spiked to an 11-year high in January on the back of an 18 per cent increase in food prices, China-watchers found themselves casting their minds back to the food price rises of 1988 and the social disturbances, protests and civil unrest that followed. Inflation is often cited as one of the factors behind the major demonstrations in 1989. 

    飆升的食品價(jià)格也令人想起了距今更近的一些擔(dān)憂。今年1月，隨著食品價(jià)格上漲18%，中國(guó)折合成年率的通脹水平達(dá)到11年高點(diǎn)，中國(guó)觀察家們不禁回想到1988年的食品價(jià)格上漲，以及隨后的社會(huì)動(dòng)蕩、抗議浪潮和民心不安。人們通常認(rèn)為，通脹是造成1989年大規(guī)模游行示威的原因之一。

    This rise in prices is a consequence of both demand and supply trends. On the demand side, the key factor has been the strong consumption growth in emerging markets, which in turn has been powered by those countries' impressive income gains. China, for example, has accounted for up to 40 per cent of the increase in global consumption of soyabeans and meat over the past decade. At the same time, a series of supply-side disruptions in key commodity markets ranging from drought to disease have been at work. 

    這種價(jià)格上漲是供需兩方面趨勢(shì)的結(jié)果。在需求方面，關(guān)鍵因素在于新興市場(chǎng)消費(fèi)的強(qiáng)勁增長(zhǎng)——這些國(guó)家收入的大幅增加推動(dòng)了消費(fèi)的增長(zhǎng)。以中國(guó)為例，過(guò)去十年，在全球大豆和肉類消費(fèi)增長(zhǎng)中，中國(guó)所占的比例達(dá)到40%。與此同時(shí)，在關(guān)鍵的大宗商品市場(chǎng)上，干旱和疾病等因素造成的一系列供應(yīng)方面的中斷也發(fā)揮了作用。

    Perhaps the most important drivers of price gains over the past year are developments in world energy markets. High oil prices have encouraged a policy focus on biofuels, including lashings of generous financial support. Production has responded quickly to these incentives: the World Bank reports that the US has used 20 per cent of its maize production for biofuels and the European Union 68 per cent of its vegetable oil production. This change in usage has boosted prices, reduced the supply of these crops available for food and encouraged the substitution of other agricultural land from food to biofuel production.

    也許，過(guò)去一年價(jià)格上漲的最大推動(dòng)力量是全球能源市場(chǎng)的發(fā)展。高油價(jià)鼓勵(lì)了集中發(fā)展生物燃料的政策，包括提供大量慷慨的財(cái)政支持。生產(chǎn)方面也迅速對(duì)這些激勵(lì)措施做出了反應(yīng)：世界銀行(World Bank)的報(bào)告顯示，美國(guó)已經(jīng)將20%的玉米產(chǎn)量用于生物燃料，歐盟用于生物燃料的植物油產(chǎn)量達(dá)到68%。用途上的變化推動(dòng)了價(jià)格的上揚(yáng)，減少了這些農(nóng)作物的糧食供應(yīng)，鼓勵(lì)了其他農(nóng)業(yè)用地從糧食生產(chǎn)轉(zhuǎn)向生物燃料生產(chǎn)。

    This is not the first time in modern economic history that the Malthusian spectre of global food shortages has stalked the world economy. Surges in food prices in the 1970s and then again in the mid-1990s both prompted warnings that agricultural capacity was failing to keep pace with a growing world population. Each time, the prices jumped it proved to be temporary as supply responded. There are good reasons for believing that this latest bout of market disequilibrium will ultimately reach the same resolution. That said, however, there are two important caveats to set against such an optimistic reading of current circumstances.

    馬爾薩斯關(guān)于全球食品短缺的幽靈追隨著世界經(jīng)濟(jì)的發(fā)展，這在現(xiàn)代經(jīng)濟(jì)史上不是第一次。上世紀(jì)70年代以及90年代中期食品價(jià)格的飆升，都曾向世人發(fā)出警告：農(nóng)業(yè)產(chǎn)能無(wú)法跟上世界人口的增長(zhǎng)。隨著供給作出反應(yīng)，每一次價(jià)格的躍升都是暫時(shí)的。人們有充分的理由相信：最近這一輪市場(chǎng)失衡最終會(huì)以同樣的方式得到解決。但即便如此，針對(duì)對(duì)當(dāng)前環(huán)境如此樂(lè)觀的解讀，我還是要提出兩項(xiàng)重要告誡。

    First, the lag in supply response to the stimulus provided by higher prices may prove to be of greater duration than its predecessors, to the extent that the current changes in world energy markets – and hence the associated demand for biofuels – are likely to be lasting ones. With climate change and environmental degradation threatening agricultural capacity in several key regions, the elasticity of past supply responses may prove to be a poor guide to the future.

    第一，面對(duì)價(jià)格上漲的刺激，供給方面的反應(yīng)可能會(huì)比前幾次更為滯后，因?yàn)楫?dāng)前世界能源市場(chǎng)的變化，以及由此產(chǎn)生的相關(guān)生物燃料需求，可能會(huì)持續(xù)相當(dāng)長(zhǎng)一段時(shí)間。由于氣候變化和環(huán)境惡化威脅到幾個(gè)關(guān)鍵地區(qū)的農(nóng)業(yè)產(chǎn)能，過(guò)去供給反應(yīng)的彈性，可能無(wú)法很好地體現(xiàn)未來(lái)的狀況。

    Second, during the extended period in which supply continues to lag behind demand there are likely to be significant social and economic costs. Three in particular stand out. 

    第二，在供給長(zhǎng)期滯后于需求期間，可能存在巨大的社會(huì)與經(jīng)濟(jì)成本。有3方面特別值得注意。

    Most important, a period of protracted higher food prices will be bad news for many of the world's poorest people and its poorest economies. While the share of food in the consumption basket of a rich country such as the US is relatively low, at about 10 per cent, it averages about 30 per cent in China and more than 60 per cent in sub-Saharan Africa. Those countries that are most vulnerable are the low-income net food importers. Higher food prices add more strain to import bills that have often already been stretched by higher energy prices. Several of the poorest economies fall into this category and are heavily dependent on food aid to meet their needs. But the worldwide volume of such aid has stagnated for the past two decades and, what is worse, the quantity of aid delivered tends to fall as prices rise, given that a large proportion comprises a fixed annual dollar amount.

    最重要的是，食品價(jià)格長(zhǎng)期處于高位，對(duì)許多世界上最貧困的人口和最貧窮的經(jīng)濟(jì)體將是一個(gè)噩耗。盡管在美國(guó)等富裕國(guó)家的消費(fèi)籃子中，食品所占比例相對(duì)較小，僅為10%左右，但中國(guó)的平均水平約為30%，而撒哈拉以南非洲國(guó)家則超過(guò)了60%。最容易受到傷害的國(guó)家是那些低收入的食品凈進(jìn)口國(guó)。食品價(jià)格的上漲，會(huì)給通常已經(jīng)不堪油價(jià)上漲重荷的進(jìn)口賬單帶來(lái)更大壓力。有幾個(gè)最貧窮經(jīng)濟(jì)體就屬于這一類，它們嚴(yán)重依賴于食品援助來(lái)滿足自身需要。但過(guò)去20年，全球這類援助的數(shù)量一直沒(méi)有增加。更糟糕的是，鑒于很大一部分援助由每年固定數(shù)額的美元構(gòu)成，隨著價(jià)格上漲，派發(fā)的援助數(shù)量也會(huì)呈現(xiàn)下降趨勢(shì)。

    Next, there are important social strains to be managed. These may be particularly problematic for those emerging markets that are already struggling to deal with the consequences of growing inequality. Granted, higher food prices are something of a two-edged sword here, since higher agricultural earnings could reduce rural-urban income disparities. But the big losers are likely to be the urban poor, typically a politically volatile group, while many of the rural poor will also suffer.

    其次，各國(guó)需要應(yīng)對(duì)重要的社會(huì)壓力。一些新興市場(chǎng)已經(jīng)在疲于應(yīng)付不平等現(xiàn)象加劇帶來(lái)的后果，對(duì)這些市場(chǎng)而言，應(yīng)對(duì)重要的社會(huì)壓力可能就會(huì)更成問(wèn)題。就算食品價(jià)格上漲是一把雙刃劍——因?yàn)檗r(nóng)業(yè)收入增加會(huì)縮小城鄉(xiāng)收入差距，但受害最深的困難是城市貧困人口，通常是政治不穩(wěn)定的團(tuán)體，而許多農(nóng)村貧困人口同樣也會(huì)受累。

    Finally, higher food prices will call for tighter monetary policy. Given the disparity in the share of food in consumption baskets, and the fact that rich country central banks tend to exclude food prices from their core inflation measures, the policy reaction will tend to be greater in developing economies. Authorities may also be tempted by price controls and other direct measures. However, rich country central banks will also have to keep a close watch on any spillover effects that tighter monetary policy could have on non-food prices.

    最后，食品價(jià)格上漲會(huì)要求各國(guó)收緊貨幣政策。鑒于食品在消費(fèi)籃子中所占比例的差異，以及富國(guó)央行往往不把食品價(jià)格納入核心通脹指標(biāo)的事實(shí)，發(fā)展中國(guó)家經(jīng)濟(jì)體可能會(huì)做出更大的政策反應(yīng)。各國(guó)政府也許還會(huì)考慮采取價(jià)格管制和其他直接措施。然而，富國(guó)央行也會(huì)不得不密切關(guān)注從緊貨幣政策可能對(duì)非食品價(jià)格產(chǎn)生的溢出效應(yīng)。