秋千影/译

The worlds most important crop is fuelling climate change and diabetes.全球最重要的粮食作物正在加重气候变化及糖尿病病情。

The green revolution was one of the greatest feats of human ingenuity. By promoting higher-yielding varieties of wheat and， especially， rice， plantbreeders in India， Mexico and the Philippines helped India avoid a famine. From 1965 to 1995 Asias rice yields doubled and its poverty almost halved， even as its population soared.

绿色革命是人类智慧之伟绩。通过推广高产的小麦和水稻品种（后者尤为重要），印度、墨西哥和菲律宾的育种专家帮助印度避免了粮荒。1965年至1995年，尽管亚洲人口激增，但水稻产量翻倍，同时，贫困人口几近减半。

Asias vast rice market is a legacy of that triumph. The starchy grain is the main source of sustenance for over half the worlds population. Asians produce over 90% of rice and get more than a quarter of their calories from it. And demand for the crop is projected to soar， on the back of population growth in Asia and Africa， another big rice consumer. By one estimate， the world will need to produce almost a third more rice by 2050. Yet that looks increasingly hard—and in some ways undesirable.

這一成就造就了亚洲庞大的大米市场，而这一淀粉粮食是世界上过半人口的生存之源。亚洲人生产超过90%的大米，也从大米获取超过四分之一的热量。非洲是大米的另一大消费市场，由于亚非的人口增长，对大米的需求预计会猛增。有人预测，到2050年，世界需要增产三分之一的水稻，但做到这一点看似越来越难，从某些方面讲，还会招致祸患。

Rice production is spluttering. Yields have increased by less than 1% a year over the past decade， much less than in the previous one. The greatest slowdowns were in South-East Asia， where Indonesia and the Philippines—together， home to 400m people—are already big importers. This has many explanations. Urbanisation and industrialisation have made labour and farmland scarcer. Excessive use of pesticides， fertiliser and irrigation have poisoned and depleted soils and groundwater. But the biggest reason may be global warming.

大米生产陷入窘境，过去的十年里，每年的产量增长不到1%，远远落后于上个十年。东南亚降幅最大，印度尼西亚和菲律宾两国人口达4亿，目前已需要大量进口大米。这个现象原因很多：城市化和工业化导致劳动力减少、农业用地稀缺；过度使用农药、化肥、灌溉导致土壤贫瘠和地下水枯竭；而最重要的原因或是全球变暖。

Rice is particularly susceptible to extreme conditions and is often grown in places where they are increasingly evident. Patchy monsoon rains and drought last year in India， the worlds biggest rice exporter， led to a reduced harvest and an export ban. Devastating floods in Pakistan， the fourth-biggest exporter， wiped out 15% of its rice harvest. Rising sea-levels are causing salt to seep into the Mekong Delta， Vietnams “rice bowl”.

水稻极易受极端天气的影响，但其种植区的极端天气却越来越明显。印度是世界最大的大米出口国，去年因为降雨稀少和干旱，导致产量减少，实行了出口限制。巴基斯坦是第四大大米出口国，但因洪水肆虐，水稻减产15%。在越南的“粮仓”湄公河三角洲，海水上涨，肥沃土壤遭盐碱侵蚀。

It gets worse. Rice is not merely a casualty of climate change， but also a contributor to it. By starving soils of oxygen， paddy cultivation encourages methane-emitting bacteria. It is a bigger source of greenhouse gas than any foodstuff except beef. Its emissions footprint is similar to that of aviation. If you count the conversion of forestland for rice paddy—the fate of much of Madagascars rainforest—that footprint is even bigger.

更糟糕的是，水稻不仅受害于气候变化，而且会加剧气候变化。水稻种植会通过消耗土壤中的氧气，滋生排放甲烷的微生物。在食物中，水稻产生的温室效应仅次于牛肉。其碳排放足迹类似于航空业的碳排放。如果把毁林造田考虑在内，比如马达加斯加大片雨林的命运，其足迹更甚。

This amounts to an insidious feedback loop1 and， in all， a far more complicated set of problems than the food insecurity that spurred the green revolution. Indeed， eating too much rice turns out to be bad for people as well as the climate. White rice is more fattening than bread or maize， and is not especially nutritious. In South Asia rice-heavy diets have been linked to high rates of diabetes and persistent malnutrition.

由此导致的具有潜在危害的反作用最终会引发一系列问题，这些问题远比激发了绿色革命的粮食危机更为复杂。消费太多大米最终的确会给人类和气候造成危害。相较于面包和玉米，白米更容易使人发胖，而且不是很有营养。在南亚地区，以米为主的餐饮习惯与糖尿病高发和长期营养不良密切相关。

Policymakers need to increase rice yields， then， but more selectively than in the 1960s. In the places most suitable for rice cultivation， such as hot and sticky South-East Asia， faster adoption of new technologies， such as flood resistant and more nutritious seeds， could provide a big productivity boost. In tandem with improved practices， such as direct seeding of paddy， they could also shorten the growing cycle and reduce the amount of water required， mitigating environmental harm. Farmers have been slow to adopt such improvements， partly because of overgenerous subsidies that shield them from the rice crisis. A better approach would make state support contingent on best practice. By encouraging crop insurance—a good idea in itself—governments could also help reassure farmers as they switch from old ways to new.

因此，虽然决策者需要增加水稻产量，但与20世纪60年代相比，应该更加有所选择。像东南亚这种闷热的最适合水稻种植的地区，应该尽快采用新技术，比如推广既具抗洪能力又更有营养的稻种，以确保增产。除了采用稻种直接种植等改良作法，同时可以缩短生长周期，从而减少水的需求量，减少对环境的危害。农人一直懒于采用改良做法，部分原因在于过度慷慨的补贴让他们对水稻危机缺乏切身感受。国家须改进策略，基于种植方法来发放补贴。各国政府还可以通过提供作物保险——这本身是个好点子——让农人在更新技术时感到安心。

Governments need to nudge producers and consumers away from rice. India and Indonesia are promoting millet， which is more nutritious and uses a lot less water. Scrapping subsidies that favour rice over other crops would make such efforts more effective. India， for example， procures rice from farmers， often at above-market rates， then distributes it as food aid. It should make its interventions more crop-agnostic， by replacing subsidies and free rice with income support for farmers and cash transfers for the poor. That would encourage farmers to choose the best crop for their local conditions—much of Indias agricultural north-west would switch from rice to wheat overnight. Poor Indians would be free to choose a more balanced diet. Thereby， it would correct a market skewed towards en-vironmental damage and poor health.

各國政府应该推动种植者和消费者逐渐摆脱对稻米的依赖。印度和印度尼西亚正在推广粟类作物，因为这类作物更有营养，且用水少得多。如能废除水稻优于其他作物的种植补贴，成效将更加显著。比如，印度政府从稻民手中通常以高于市场的价格购得大米，然后以食物援助的形式发放下去。政府的干预措施应该减少针对特定作物，停止发放补贴和免费大米，转而给农人提供收入支持，给贫困人口提供现金支持，以此鼓励农人因地制宜地选择作物——这样的话，印度西北部农业区的大部分地区会在一夜之间由水稻改种小麦。印度的穷人将自主选择更均衡的饮食。如此一来，倾向于破坏环境、危害健康的市场将得以改观。

Bringing about such change in Asia and beyond will be far harder than promoting new wonder seeds was. Farmers are almost everywhere a powerful consti-tuency. Yet policymakers should get used to blending complicated economic and technological fixes in this way. Increasingly， it is what fighting climate change will entail. Sorting out the mounting crisis in the worlds most important foodstuff would be a good place to begin.

在亚洲及其他地区，推行这样的改良远远难于推广神奇稻种。在任何地区，农民总是最强有力的选民群体。但是，决策者应该习惯于用这种方式将复杂的经济与技术改进融为一体。这越来越成为对抗气候变化的必由之路。解决全世界最重要的粮食领域日益严重的危机将是首要抓手。