导读：截至今日，云南、贵州、广西、重庆、四川5省区市耕地受旱面积1.01亿亩、占全国的84%，作物受旱7907万亩，待播耕地缺水缺墒2197万亩；有2088万人、1368万头大牲畜因旱饮水困难。如此严重的旱灾不得不令人反思，我们做错了什么，今后将怎么做。

 

For those of us lucky enough to always have enough food and water, it may be hard to imagine living through a drought. A drought occurs for a variety of reasons, usually including a lack of rainfall and warm temperatures.Soil moisture severely dwindles. Why and how do these meteorological events occur?

对于那些幸运的、总有足够的食物和水的人来说，很难想象在干旱之中的生活。引发干旱有多种原因，通常包括缺少降水和高温。土壤中的水分严重减少。这个气象现象的成因和原理又是什么呢？

As air swirls around the earth, it rises and sinks over different areas of the globe. When air rises it cools and loses moisture. When air sinks, it grows warmer and absorbs moisture, drying out the land. Sinking air helps to form deserts, such as the Sahara Desert in Africa.

空气在地球上方旋转流动，沉浮于不同的地区。当空气上升时，温度降低，失去水分。当空气下降时，温度上升，吸收水分，致使地面干燥。下沉的空气是撒哈拉（在非洲）等沙漠形成的帮凶。

Warm, sinking air can hamper cloud formation, which results in less rain and lower overall humidity. When these conditions occur in an area that normally receives enough rain to allow plants to grow and keep water sources replenished, a drought can ensue. The Dust Bowl that affected the prairie regions of the United States was one infamous drought. An equally severe drought occurred in the United States in the summer of 1988. Rainfall over the mid-west, Northern Plains, and the Rockies was fifty to eighty-five percent below normal.

温暖、下沉的空气能够阻碍云的形成，致使降雨减少，空气和土壤的湿度降低。这种状况如果是发生在平时雨水充足，能让植物生长，并通过植物保存水分的地方，旱灾就会随之而来。沙尘天气波及到了美国的大草原地区，造成了十分严重的旱灾。在1988年的夏天，美国也曾发生过同样严重的旱灾。在中西部，北部平原和洛矶山脉，当时的降水量是平常的百分之五十到八十。

Sometimes over-farming and soil erosion contribute to drought, but there are also natural disasters that can occur even when soil is carefully preserved. When a drought hits, there’s little that can be done to end it. Water and soil conservation can help, but until the rains come again there’s not much science can do.

有时，过度耕种和土壤侵蚀都能造成干旱。但是，尽管有时人们很注意保护土壤，旱灾依然会发生。当干旱来临时，我们对它便束手无策了。注意水土保持能管用，但是，在雨水重归大地之前，科学家们也帮不上什么忙。