中国干旱半干旱区的环境演变与荒漠化的成因

近40年来，中国北方荒漠化的发展速率为0．81％－1．64％／a，以往人们多侧重于对当代气候因素和人为因素的研究，而忽视第四纪环境演变的影响，分析了20000年来气候，风沙，黄土和第四纪环境的演变过程，采用GIS对干冷－温湿－干冷三个气候时段的荒漠化进行了定量的对比研究，并指出10000年来青藏高原的隆升是促使北方干旱和荒漠化的重要原因，自然因素导致荒漠化的时间尺度为万年或千年，人为因素导致荒漠化的尺度为百年或10年，第四纪环境是形成荒漠化的基础，植被，土被被破坏是当代荒漠化发展的直接原因，近50年来，中国北方的气候有向干，热方向演变的趋势，因此，荒漠化的防治将是21世纪中国的一项重大任务。

Study on the Environmental Evolution and the Causes of Desertification in Arid and Semiarid Regions in China

In recent 40 years, the developing rate of desertification is 0 81%-1 64% per year in the north of China The researchers emphasize particularly climate and man made factors of present time, but over look the effect of environmental evolution on the study of desertification The authors analyze evolution process of climate, sand blown by wind, loess and environment of Quaternary since 20000 years, and have the study of quantitative and contrast, using GIS on desertification of three periods of time including dry cold, warm humid and dry cold The result indicates that the important factor to make drought and desertification in north is the uplifting of Qinghai Xizang Plateau in 10 000 years The time scale on which natural factors cause desertification is ten thousand years or thousand years, while that of human efforts is only hundred years or decade Quaternary environment is the foundation of desertification formation and the desertification of vegetation and soil covering is direct cause leading to the present desertifacation In recent 50 years, climate in the north of China evolves to dry and heat Thus, desertification protection is an important task for China in the 21st century