我国北方干旱化研究——面向国家需求的全球变化科学问题

近几十年来 ,全球环境变化已经成为国际社会关注的焦点。中国也面临一系列与此相关的重大生存环境问题。其中最为突出的是北方地区的干旱化。其主要表现为 :降水量减少 ,雪线高度抬升 ,湖泊萎缩 ,河网干枯 (特别如黄河断流 ) ,土地荒漠化 ,生态系统退化等等。这些问题已经成为国民经济发展的严重障碍。北方干旱化是怎样形成的 ?其未来发展趋势如何 ?将对中国的生存环境和社会经济可持续发展产生什么影响 ,应采取什么对策 ?政府和公众迫切要求回答这些与社会发展和人民生活密切相关的重大问题。文中分析了北方干旱化问题的性质 ,提出了面对国家需求应解决的关键科学问题和主要研究内容 ,简要介绍了在国家重点基础研究规划项目的支持下 ,近年来的主要研究进展 ,其中包括北方地区不同时间尺度干湿变化的规律和干旱化的证据 ,全球增暖和人类活动 (主要是水土资源的利用 )对干旱化的影响 ,主要生态系统对干旱化的响应和适应以及组织有序人类活动 ,改善生态环境 ,缓解干旱化影响的虚拟试验的结果等。

STUDY OF ARIDIFICATION IN NORTHERN CHINA--A GLOBAL CHANGE ISSUE FACING DIRECTLY THE DEMAND OF NATION

In recent several decades, the global environmental change has become a critical issue concerned by world society. China is also facing a series of environmental problems related to global change. Among them, the most serious one is the aridification in Northern China as shown by the reduction of precipitation, lifting of snow line, cutoff of river flow, shrinking of lake, desertification of the land and the degradation of ecosystems, etc. These problems have become the most serious obstacles for the development of national economy.What are the main causes of the aridification? What a role the human activities play in the aridifcation? What will be the trend of its future development? What are the impacts of aridifcation on the life\|supporting environment and the sustainable development of social economy? These are the great concern of the government and people.This article first analyzed the nature of the aridification problem and then identified the key scientific issues and research topics in order to answer the questions put forward by the society. The major part of the text introduced briefly the recent progress in the study of Northern China aridification under the support of National Key Basic Research Program, including the rule of dry and wet oscillation and the new and more evidences of the aridification in Northern China, the potential impacts of global warming and human activities ( mainly the land use and water resources) on the aridification, the response and adaptation of the major ecosystems to the arid climate and finally the results of virtual experiments to show how to organize the orderly human activities to improve the environmental conditions and to reduce the impacts of aridification.