好英语网地球变得更热了，大米也在面临危机
Rice is in trouble as the Earth heats up, threatening the food and livelihood of billions of people. Sometimes there’s not enough rain when seedlings need water, or too much when the plants need to keep their heads above water. As the sea intrudes, salt ruins the crop. As nights warm, yields go down.
随着地球升温，大米有麻烦了，进而威胁到数十亿人的食物与生计。有时在幼苗需要水的时候没有足够的降雨，有时稻子需要顶部保持在水面以上，却又有太多的降雨。海水倒灌，作物被盐分破坏。夜晚气温上升，导致产量下降。
These hazards are forcing the world to find new ways to grow one of its most important crops. Rice farmers are shifting their planting calendars. Plant breeders are working on seeds to withstand high temperatures or salty soils. Hardy heirloom varieties are being resurrected.
这些危险迫使世界开始寻找种植这一关键作物的新方法。稻农在改变耕种时间安排。育苗者在寻找能忍受高温或高盐土壤的种子。耐受力强的古早品种重新得到使用。
And where water is running low, as it is in so many parts of the world, farmers are letting their fields dry out on purpose, a strategy that also reduces methane, a potent greenhouse gas that rises from paddy fields.
在缺水的地方——全世界有许多地方面临这一状况，农民有意让稻田干涸，从而减少甲烷，这是一种在水稻田中产生的强效温室气体。
The climate crisis is particularly distressing for small farmers with little land, which is the case for hundreds of millions of farmers in Asia. “They have to adapt,” said Pham Tan Dao, the irrigation chief for Soc Trang, a coastal province in Vietnam, one of the biggest rice-producing countries in the world. “Otherwise they can’t live.”
气候危机对耕种小块田地的小农打击尤其大，在亚洲有数亿这样的农民。“他们只能去适应，”在越南沿海省份朔庄负责水利灌溉工作的范辛陶（音）说，“否则无法生存。”越南是世界上最大的稻米生产国之一。
In China, a study found that extreme rainfall had reduced rice yields over the past 20 years. India limited rice exports out of concern for having enough to feed its own people. In Pakistan, heat and floods destroyed harvests, while in California, a long drought led many farmers to fallow their fields.
在中国，研究发现极端降雨在过去20年里导致了大米产量的下降。印度因为担心粮食不足以喂饱自己的人民，对大米出口进行了限制。在巴基斯坦，酷热和洪水造成庄稼歉收，而在加利福尼亚，长时间的干旱导致许多田地休耕。
The challenges now are different from those 50 years ago. Then, the world needed to produce much more rice to stave off famine. High-yielding hybrid seeds, grown with chemical fertilizers, helped. In the Mekong Delta, farmers went on to produce as many as three harvests a year, feeding millions at home and abroad.
现在面临的挑战和50年前有很大不同。当时世界需要大幅提高稻米产量以应对饥荒问题。高产的杂交稻加上化肥的使用发挥了作用。在湄公河三角洲，农民开始转向一年三熟的生产，给本国乃至国外数以百万计的人提供粮食。
Today, that very system of intensive production has created new problems worldwide. It has depleted aquifers, driven up fertilizer use, reduced the diversity of rice breeds that are planted, and polluted the air with the smoke of burning rice stubble. On top of that, there’s climate change: It has upended the rhythm of sunshine and rain that rice depends on.
在今天，集约耕作的体系本身也在世界各地造成了新问题。土壤蓄水层被耗尽，导致化肥使用增加，减少了稻米品种的多样性，焚烧秸秆产生的烟雾又造成空气污染。除了这些之外，还有气候变化：稻米赖以生存的光照和降雨的规律被打乱了。
Perhaps most worrying, because rice is eaten every day by some of the world’s poorest, elevated carbon dioxide concentrations in the atmosphere deplete nutrients from each grain.
最令人忧心的可能是，由于世界上许多最穷困的人每天食用稻米，大气中二氧化碳浓度的增加可能会导致谷粒的营养匮乏。
Rice faces another climate problem. It accounts for an estimated 8 percent of all global methane emissions from human activity. That’s a fraction of the emissions from coal, oil and gas, which together account for 35 percent of methane emissions. But fossil fuels can be replaced by other energy sources. Rice, not so much. Rice is the staple grain for an estimated three billion people. It is biryani and pho, jollof and jambalaya — a source of tradition, and sustenance.
大米还面临另一个气候问题。人类活动产生的全球甲烷排放大约有8%来自稻米种植。这跟占35%的煤炭、石油、天然气排放比起来是大巫见小巫。但是化石燃料可以用其它能源替代。大米则没那么容易。它是全球约30亿人的主食。它是印度香饭、越南河粉、西非加罗夫饭和克里奥尔什锦饭——是传统与营养的来源。
“We are in a fundamentally different moment,” said Lewis H. Ziska, a professor of environmental health sciences at Columbia University. “It’s a question of producing more with less. How do you do that in a way that’s sustainable? How do you do that in a climate that’s changing?”
“我们正处于一个完全不同的时刻，”哥伦比亚大学环境健康科学教授刘易斯·齐斯卡说。“这是一个用更少的资源生产更多产品的问题。你如何以一种可持续的方式做到这一点？在气候不断变化的情况下，你如何做到这一点？”
A risky balance: Rice, or shrimp?
一个危险的平衡：水稻还是虾？
In 1975, facing famine after war, Vietnam resolved to grow more rice.
1975年，面对战后的饥荒，越南决定种植更多的水稻。
It succeeded spectacularly, eventually becoming the world’s third-largest rice exporter after India and Thailand. The green patchwork of the Mekong Delta became its most prized rice region.
它取得了惊人的成功，最终成为仅次于印度和泰国的世界第三大大米出口国。绿色的湄公河三角洲成为该国最珍贵的稻米产区。
At the same time, though, the Mekong River was reshaped by human hands.
然而，与此同时，湄公河被人类的双手重塑了。
Starting in southeastern China, the river meanders through Myanmar, Laos, Thailand and Cambodia, interrupted by many dams. Today, by the time it reaches Vietnam, there is little freshwater left to flush out seawater seeping inland. Rising sea levels bring in more seawater. Irrigation canals turn salty. The problem is only going to get worse as temperatures rise.
湄公河发源于中国东南部，蜿蜒流经缅甸、老挝、泰国和柬埔寨，其间被许多水坝阻断。今天，当它到达越南时，几乎没有淡水可以冲掉渗入内陆的海水。海平面上升带来了更多的海水。灌溉渠变咸。随着气温的升高，这个问题只会变得更糟。
“We now accept that fast-rising salty water is normal,” said Mr. Pham, the irrigation chief. “We have to prepare to deal with it.” Where saltwater used to intrude 30 kilometers or so (about 19 miles) during the dry season, he said, it can now reach 70 kilometers inland.
“我们现在承认，海水快速上涨是正常的，”灌溉主管范先生说。“我们必须做好应对的准备。”他说，过去在旱季，海水侵入内陆30公里左右的地方，现在可以到达内陆70公里。
Climate change brings other risks. You can no longer count on the monsoon season to start in May, as before. And so in dry years, farmers now rush to sow rice 10 to 30 days earlier than usual, researchers have found. In coastal areas, many rotate between rice and shrimp, which like a bit of saltwater.
气候变化还带来了其他风险。你不能再指望季风季节像以前一样，从5月开始。因此，研究人员发现，在干旱年份，农民现在比平时提前10到30天播种水稻。在沿海地区，许多人在种水稻和养虾之间轮换——虾喜欢有一点咸水。
But this requires reining in greed, said Dang Thanh Sang, 60, a lifelong rice farmer in Soc Trang. Shrimp bring in high profits, but also high risks. Disease sets in easily. The land becomes barren. He has seen it happen to other farmers.
但这需要控制贪婪，60岁的朔庄省稻农邓清生（音）说。虾带来了高利润，但也带来了高风险。疾病很容易发作。土地变得贫瘠。他看到其他农民也遇到这种情况。
So, on his seven acres, Mr. Dang plants rice when there’s freshwater in the canals, and shrimp when seawater seeps in. Rice cleans the water. Shrimp nourishes the soil. “It’s not a lot of money like growing only shrimp,” he said. “But it’s safer.”
因此，在他2.8万平米的土地上，当运河里有淡水时，邓清生就种水稻，当海水渗入时，他就养虾。水稻可以净化水质。虾能滋养土壤。“不像只养虾那么赚钱，”他说。“但是这样更安全。”
Elsewhere, farmers will have to shift their calendars for rice and other staple grains, researchers concluded in a recent paper. Scientists are already trying to help them.
研究人员在最近的一篇论文中得出结论，在其他地方，农民将不得不改变种植水稻和其他主要谷物的日程安排。科学家们已经在试图帮助他们。
Secrets of ancient rice
古代水稻的秘密
The cabinet of wonders in Argelia Lorence’s laboratory is filled with seeds of rice — 310 different kinds of rice.
在阿格利亚·劳伦斯的实验室里，陈列柜里装满了水稻的种子——310种不同的水稻。
Many are ancient, rarely grown now. But they hold genetic superpowers that Dr. Lorence, a plant biochemist at Arkansas State University, is trying to find, particularly those that enable rice plants to survive hot nights, one of the most acute hazards of climate change. She has found two such genes so far. They can be used to breed new hybrid varieties.
许多是现在很少生长的古老品种。但它们拥有阿肯色州立大学植物生化学家劳伦斯博士正在努力寻找的基因超能力，尤其是那些能让水稻在炎热的夜晚存活下来的基因，炎热的夜晚是气候变化最严重的危害之一。到目前为止，她已经发现了两个这样的基因。它们可以用来培育新的杂交品种。
“I am convinced,” she said, “that decades from now, farmers are going to need very different kinds of seeds.”
“我确信，”她说，“几十年后，农民将需要非常不同种类的种子。”
Less watery rice paddies?
少水的稻田？
Rice is central to the story of the United States. It enriched the coastal states of the American South, all with the labor of enslaved Africans who brought with them generations of rice-growing knowledge.
水稻位于美国历史的中心。它使美国南部沿海各州富裕起来，这一切都得益于非洲奴隶的劳动，他们带来了几代人的水稻种植知识。
Today, the country’s dominant rice-growing area is spread across the hard clay soil near where the Mississippi River meets one of its tributaries, the Arkansas River. It looks nothing like the Mekong Delta. The fields here are laser-leveled flat as pancakes. Work is done by machine. Farms are vast, sometimes more than 20,000 acres.
今天，这个国家主要的水稻种植区分布在靠近密西西比河与其支流之一阿肯色河交汇处的坚硬粘土地上。它看起来与湄公河三角洲大不相同。这里的田地被激光平整得像煎饼一样。工作是由机器完成的。农场面积很大，有时超过8000万平米。
What they share are the hazards of climate change. Nights are hotter. Rains are erratic. And there’s the problem created by the very success of so much intensive rice farming: Groundwater is running dangerously low.
他们共同面对的是气候变化的危害。夜晚更热。降雨不稳定。如此大量的集约化水稻种植带来了一个问题：地下水正处于危险的低水平。
Enter Benjamin Runkle, an engineering professor from the University of Arkansas at Fayetteville. Instead of keeping rice fields flooded at all times, as growers have always done, Dr. Runkle suggested that Arkansas farmers let the fields dry out a bit, then let in the water again, then repeat. Oh, and would they let him measure the methane coming off their fields?
来自费耶特维尔阿肯色大学的工程学教授本杰明·朗克尔进入了这个领域。朗克尔建议，阿肯色州的农民不要像以往那样一直让稻田被水淹没，而是让稻田干一点，然后再浇水，如此重复。哦，他们会让他测量他们田地里的甲烷吗?
Mark Isbell, a second-generation rice farmer, signed up.
第二代稻农马克·伊斯贝尔报名参加。
On the edge of Mr. Isbell’s field, Dr. Runkle erected a tall white contraption that an egret might mistake for a cousin. The device measured the gases produced by bacteria stewing in the flooded fields. “It’s like taking a breathalyzer test of the land,” Dr. Runkle said.
在伊斯贝尔的田地边上，朗克尔竖起了一个高大的白色装置，白鹭可能会把它误认为自己的表亲。该装置测量水田中的细菌产生的气体。“这就像对土地进行酒精测试，”朗克尔博士说。
His experiment, carried out over seven years, concluded that by not flooding the fields continuously, farmers can reduce rice methane emissions by more than 60 percent.
他的实验进行了七年多，得出的结论是，通过不持续淹没田地，农民可以减少60%以上的水稻甲烷排放。
“We kind of look over the hill and see what’s coming for the future, and learn now,” said his father, Chris Isbell.
马克·伊斯贝尔的父亲克里斯·伊斯贝尔说：“我们是在看看未来会发生什么，然后现在就学习。”