气候变化对陆地生态系统和海岸带地区的影响解读

Interpretation of IPCC Fifth Assessment Report on Impacts of Climate Change on Terrestrial Ecosystems and Coastal Areas

IPCC第五次评估报告认为，受气候变化影响，许多生物种及生态系统已经发生显著变化，未来这些变化还将继续。气候变化和人类活动的共同作用将对21世纪的陆地生态系统和内陆水系统产生重要影响，大部分陆地和淡水物种灭绝的风险都将增加，部分地区可能会发生不可逆转的变化。未来仅依靠生态系统自身的适应能力将不足以应对这些变化，需要辅以适应措施帮助生态系统适应气候变化。海岸带系统和低洼地区除了受气候变化的影响，还受到人类活动的强烈影响，并且影响的方式和结果因地而异。预计到2100年，全球平均海平面将上升0.28～0.98 m，相对海平面上升差异较大。到2100年，数以亿计的人将受到沿海洪水的影响。未来海岸带地区适应的相对成本会有很大的区域差异。在全球尺度上，采取防御措施取得的效益仍要高于不作为而付出的社会经济成本。发达国家比发展中国家具有更强的适应气候变化能力，可持续发展的气候恢复力也更大。

Working Group II contribution to IPCC Fifth Assessment Report was issued recently, it concluded that many biota and ecosystems have been affected significantly due to climate change, and these changes will be continued in the future. Climate change and human activities are projected to be powerful stressors on terrestrial and freshwater ecosystems in the 21st century, the extinction risk of many species will increase, and some ecosystems will change irreversibly. The inherent capacity of ecosystems will be insufficient to cope with projected climate change in the future, adaptation strategies and actions can increase the adaptive capacity of species and ecosystems to climate change. Coastal systems and low-lying areas are affected strongly by climate change and human activities, the consequences of impact vary from place to place. The global mean sea level rise is projected to be 0.28 -0.98 m by 2100, relative sea level rise is different with regional variations. Hundreds of millions of people will be affected by coastal flooding by 2100. The relative costs of adaptation vary strongly between and within regions and countries for the 21st century. The benefits of protecting against increased coastal flooding and land loss are larger than the social and economic costs of inaction at the global scale. The adaptive capacity of coastal areas has progressed much more significantly in developed countries than in developing countries, and so does the climate resilience of sustainable development.