1998年夏秋 ,我国长江、松花江、嫩江百年不遇的特大洪水 ,无不使人触目惊心。近年来 ,全球的“自然灾害”日趋频繁和严重 ,气候变暖、两极冰雪融化、生物大片死亡、海平面升高、特大洪水、严重干旱、大河断流 ,以及大气污染、公害事件增加、疑难病增加、土地贫瘠化、土地沙漠? In the summer and autumn of 1998, all the extraordinary floods in the Yangtze River, Songhua River and Nen River in the past hundred years in our country were all astonishing. In recent years, the “natural disasters” in the world have become increasingly frequent and severe. The problems of climate warming, melting of polar ice and ice, death of large biological units, rising sea levels, catastrophic floods, severe droughts, Illness increases, the land is poor, the land desert?