Editor's Note

摘要

A lthough 70 percent of the earth's surface is composed of wa- ter, only 3 percent of that water is freshwater, and two-thirds of that is trapped in ice caps and glaciers. In fact, there is very little water available worldwide for the purposes of drinking, agri- culture, and sanitation, and the demand for this finite resource is rapidly increasing as the world's population burgeons exponentially. Today 6.7 billion people must share the same quantity of water that was available to the 300 million people who inhabited the earth during Roman times. The 2009 World Water Forum, held in Istanbul, Turkey, in March and attended by more than 33,000, sounded warnings that half the world's population will be affected by water shortages by 2030 and that millions of people will become refugees forced to abandon their homelands because they will no longer be able to sustain themselves as a consequence of these shortages.