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冰川是极端寒冷地区多年降雪不断积累、变质形成的自然冰体,这种冰体在重力或热力作用下沿着一定地形向低海拔地区运动。全球冰川主要分布在南北两极、中低纬度的高山带,如中国西部的中亚高山高原区、南美洲安第斯山等都有大量冰川存在。地球上陆地面积的11%被冰川、冰盖所覆盖,这些冰体储存了全球淡水资源的4/5,而其中的98%储存在遥远的南极大陆与格陵兰岛。那些分布在中低纬度临近人类常驻地的冰川虽然在全球冰川资源中所占比例很小,但其年复一年提供的大量融水却是人类活动不可或缺的重要淡水资源。
Glaciers are natural ice bodies that accumulate and degenerate after years of snowfall in extremely cold regions. Such ice bodies move along a certain terrain to lower elevations under the influence of gravity or heat. The global glaciers are mainly distributed in the northern and southern poles. The alpine belts in the middle and low latitudes, such as the Central Asia Alpine Plateau in western China and the Andes in South America, have a large number of glaciers. Eleven percent of the Earth’s land area is covered by glaciers and ice sheets, which store about four-fifths of the world’s freshwater resources, of which 98% are stored in the far Antarctic continent and Greenland. Although glaciers located near human settlements in the low and mid latitudes are a small proportion of the global glacier resources, the large amount of meltwater they provide year after year is an important freshwater resource indispensable to human activities.