地球上有70％的面积覆盖着水,而其中只有不到1％是供人类饮用的淡水,包括雨、雪水、湖泊、河流中的水以及泉水和地下水。地球上的年平均降雨量大约为650毫米,这对大多数农作物来讲是远远不够的。这些事实告诉我们,淡水必须用最经济有效的方式来加以管理。 Seventy percent of the Earth’s surface is covered with water, of which less than 1% is fresh water for human consumption, including rain, snow, lakes, water in rivers, springs and groundwater. The annual average rainfall on Earth is about 650 millimeters, which is far from enough for most crops. These facts tell us that freshwater must be managed in the most cost-effective way.