全球气候变暖与未来发展趋势

根据全球及中国气温观测资料分析了近百年全球变暖问题,指出总的变暖趋势对认为温室效应的加剧是气候变暖的原因的意见有利。但温度变化的时空分布则与温室效应的理论结果有不少不一致之处,如变暖的突变性,50年代到70年代的变冷、80年代大洋北部的变冷及中国南部的变冷等。根据代用资料建立的数百年气温序列表明,19世纪是小冰期中的一个冷期。因此,如果从这时开始计算变暖幅度,则可能过高估计了温室效应。

GLOBAL CLIMATE WARMING AND ITS TREND IN THE FUTURE

Global climate warming was examined by means of temperature observations in Chinaand around the world.It has been established that the average global temperature increased0.4—0.5℃ from the 1880s to the 1980s.This temperature increase was a little less than thatof 0.5—0.6℃ in the Northern Hemisphere.The overall warming which predominated over allthe latitudes and seasons seems to support the theory that the warming is due to the increased abundance of CO2 and other trace gases in the atmosphere.However,a series of observational facts was in contradiction to the greenhouse theory:1.The warming found for the last one hundred years or so was inhomogeneous in the timedomain.The overall warming was consisted of three abrupt changes,which occurred in about1895,1920 and 1980 AD respectively.But the increasing of the greenhouse gases was sustainedand continuous.2.The cooling between the 1950s and the mid-1970s predominated over the NorthernHemisphere can hardly be interpreted by the greenhouse effect,because the greenhouse gases hadincreased significantly during that period.3.The maximum warming in the 1980s——the warmest decade for the last one hundredyears was not found in the north of the North Pacific and North Atlantic where the surfaceair temperature in the 1980s was lower than the normal （1951-1980） and the average of 1970s.This was inconsistent with that suggested by the climate simulation of doubled concentration ofCO?.4.Temperature increased from the 1970s to the 1980s in China,but the increment wasmuch less than that in the Northern Hemisphere or the globe.In fact,the warming was limitedin Northeast and North China.In the south,temperature anomaly of the 1980s was negative,es-pecially along the Changjiang River.The aforementioned statements provide good evidence that there are some factors otherthan the greenhouse effect,at least partly responsible for the temperature variations,especiallyin local scale.Reconstructed temperature series for the Northern Hemisphere and for China demon-strated that the last phase of the little Ice Age occurred in the 19th century.The temperaturevariations for the last millennium suggested that the climate in winter in the 10th century wasprobably as warm as in the middle of the 20th century.It indicated that the warming observed for the last one hundred years can be at some ex-tent interpreted as the nature variability.Then,attributing the 0.5-0.6℃ warming only to thegreenhouse effect will overestimate the role of increasing of the greenhouse gases,and under-estimate the delaying effect of the oceans and the impacts of other factors.Finally,the factors probably responsible for the natural variability of the climate,suchas solar activity and volcano eruptions were examined.The possible trend of the global warm-ing in the future was discussed.