【摘要】 政府间气候变化专门委员会(IPCC)第二工作组于2007年4月6日正式发布了第四次评估报告,该报告客观、全面而审慎地评估了气候变化已有的和未来的可能影响。现有观测证据表明,人为增暖可能已对许多自然和生物系统产生了可辨别的影响,但由于适应以及非气候因子的作用,许多影响还难以辨别。21世纪中期,某些中纬度和热带干旱地区年平均河流径流量和可用水量会减少10%～30%;如果全球平均温度增幅超过1．5～2．5℃,目前所评估的20%～30%动植物物种可能面临灭绝的风险会增大;从全球角度看,局地平均温度增加1～3℃．预计粮食生产潜力会增加,但若超过这一范围,则会减少。兼顾适应和减缓的措施能够降低气候变化相关风险。更多还原

【Abstract】 “Climate Change 2007:Impacts,Adaptation and Vulnerability”,the Working GroupⅠcontribution to the IPCC Fourth Assessment Report(AR4)was launched on April 6,2007.This report summarize the newest peer- reviewed and comprehensive findings from international scientific communities on impact and adaptation.The observed evidence shows that it is likely that anthropogenic warming has had a discernible influence on many physical and biological systems,but many are difficult to discern due to adaptation and non-climatic factors.By the mid-21th century,annual average river runoff and water availability are projected to decrease by 10%～30% over some dry regions at mid-latitudes and in the dry tropics;Approximately 20%～30% of plant and animal species assessed so far are likely to be at increased risk of extinction if increases in global average temperature exceed 1.5～2.5℃;Globally,the potential for food production is projected to increase with increases in local average temperature over a range of 1～3℃,but above this it is projected to decrease.A portfolio of adaptation and mitigation measures can diminish the risks associated with climate change.更多还原