(单词翻译:单击)
The challenges now are different from those 50 years ago. Then, the world needed to produce much more rice to stave off famine.
现在的挑战与50年前不同。当时，世界需要生产更多的大米来避免饥荒。
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.
用化肥种植的高产杂交种子起到了助益。在湄公河三角洲，农民继续每年收获多达三次的作物，养活了国内外数百万人。
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.
如今，正是这种集约化生产体系在世界范围内造成了新的问题。这种体系耗尽了含水层里的水，增加了化肥的使用，减少了种植的水稻品种的多样性，燃烧稻茬产生的烟雾也污染了空气。
On top of that, there's climate change: It has upended the rhythm of sunshine and rain that rice depends on. 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.
此外还有气候变化：气候变化打破了水稻赖以生存的光照和降雨节奏。也许最令人担忧的是，因为世界上最贫困的一些人每天都吃大米，而大气中二氧化碳浓度的升高会耗尽每一粒稻米中的营养物质。
Rice faces another climate problem. It accounts for an estimated 8 percent of global methane emissions.
水稻还面临着另一个气候问题。据估计，水稻占全球甲烷排放总量的8%。
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.
这只是煤炭、石油和天然气排放量的一小部分，这三种排放加起来占甲烷排放量的35%。但化石燃料可以被其他能源取代。水稻的替代物就不是那么多了。
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.
据估计，大米是30亿人的主食。它是印度香饭和越南河粉，它是西非的加罗夫饭和美国南部的什锦烩饭，它是一种传统和食物之源。
"We are in a fundamentally different moment," said Lewis 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，"这是一个少投入多产出的问题。如何以一种可持续的方式做到这一点？如何在气候不断变化的情况下做到这一点？"
In 1975, facing famine after war, Vietnam resolved to grow more rice. 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.
1975年，面对战后的饥荒，越南决心种植更多水稻。越南取得了惊人的成功，最终成为仅次于印度和泰国的世界第三大稻米出口国。湄公河三角洲的绿色稻田成为其最受重视的稻米产区。
At the same time, though, the Mekong River was reshaped by human hands. Starting in southeastern China, the river meanders through Myanmar, Laos, Thailand and Cambodia, interrupted by many dams.
然而，与此同时，湄公河也被人类的双手重塑。这条河发源于中国的东南部，蜿蜒流经缅甸、老挝、泰国和柬埔寨，途中有许多大坝拦截。
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.
如今，当它到达越南时，河里几乎没有淡水可以冲走渗入内陆的海水。海平面上升带来了更多的海水。灌溉水渠变咸了。随着气温的上升，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.
"我们现在接受了海水迅速上升是常态，"灌溉主管彭先生说，"我们必须做好应对的准备。"他说，过去在旱季海水入侵30公里左右(约19英里)的地方，现在海水可以侵入内陆70公里。
