全球和中国变暖特征及未来趋势

FEATURES AND TENDENCY OF GLOBAL WARMING AND ITS IMPLICATIONS FOR CHINA

自小冰期在上世纪末结束以来，全球气温波动上升，至本世纪８０年代全球平均上升了０．４５±０．１５℃。２０～３０年代的强烈升温（＞０．３℃）归因于自然回暖，６０年代至７０年代初出现北半球为主的一度降温，８０年代又强烈升温至今未息，这次升温以冬季和夜间变暖为主，高纬度地区又大于中低纬度地区，可认为是人为的ＣＯ２等温室气体增加起了重要作用。中国２０～３０年代升温，６０年代降温和８０年代北部地区升温均大于全球平均值。全球降水变化远比温度变化复杂，总趋势略有上升，中国基本处在中纬度降水减少带中，呈现暖干化趋势。在２０年代和６０年代有两次变旱的气候跃变，相伴着旱灾的加重，但降水变率很大，洪涝灾害更为严重。未来气候主要取决于ＣＯ２及其它微量气体增加所加犟的温度效应，全球继续并持久变暖。根据政府间气候变化委员会（ＩＰＣＣ）预测的下世纪温室气体排放，Ｈｕｌｍｅ等（１９９２）综合新近若干模式研究结果，预期全球平均升温最佳估计值到２０５０年为１．２℃（低限与高限范围为０．８℃和１．８℃），而到２１００年为２．５℃（变化范围１．６～３．８℃），中国到２０５０年升温值在东部和东南部为１．０～１．５℃，在东北、华北和西部为１．

Since the end of Little Ice Age during the last century,the global temperature has undulately risen,up to the eighties of 20th century,global mean temperature has risen by (0 45±0 15)℃.A marked rise in the twenties to thirties might mainly be caused by natural factors,in the sixties to seventies,mean temperature dropped,especially in the Northern Hemisphere.Since the eighties,it has rapidly risen,the characteristics of this warming is that the temperature rising in winter or might exceeds in summer of day and in the high latitudes exceeds in the middle and low ones,it is reasonable to believe that the increase in CO 2 and the other trace gases play a key role.Correspondingly,in China,the range of mean temperatrue rising in the twenties ot thiries,droping in the sixties and rising in the north areas in the eighties totally exceed the global mean values.Change in global precipitation is more complex than that of temperature,its general trend of recent several decades is lightly inerease.China is located in the zone of decrease in precipitation of the middle latitudes and presents a warm drying trend. Accompaning twice climatic abrupt change during the twenties and sixties,drought obviously aggravated,meanwhile,the flood disaster also exacerbated due to increase in precipitation variability. Future tendency of climatic change will mainly deyend on greenhouse effect exacerbated by increase in atmospheric trace gases,future climate will be continuously warming. Hulme et al.(1992)estimated that the best estimate of global mean temperature rising in the year of 2050 is 1 2℃(0 8～1 8℃)and in the year of 2100 is 2 5℃(1 6～3 8℃),according to the scenarios of the greenhouse gases emmission by the Inter govemmental Panel on Climatic Change(IPCC) in 1990 and recent reseach results of various GCM models. In China,the mean temperature might rise 1 0～1 5℃ in the eastrn areas and south eastern areas,and 1 5～2 0℃ in the north eastern areas,northern and the western areas. Meanwhile,the precipitation woule lightly increase within the range of less than 5 precent in the great part of China,but in the northern areas,inerease in precipitation will be less than the increase of evaporation and transpriation, drought and water shortage will still be a long troublous problem, in the southern areas,especially the south eastern coastal areas,increase in precipitation and rising of sea level will also exacerbate flood and storm surge disasters. Changes in the other factors,such as solar action and volcanic eruption will fouctuate temper atuer and pricipitation variations, so the estimates above mentioned still sxist many uncentaionies. According to the state of chimate and environment of Holocene Megathermal,the climatic fluctu ation of the 21 th century will be severe and various natural dissasters will also exacerbate.