兰州大学：黄建平团队在国际著名学术刊物《Nature Climate Change》刊发气候变化最新研究成果

近日，国际著名学术刊物《Nature》旗下子刊《Nature Climate Change》发表了兰州大学大气科学学院黄建平团队关于气候变化的最新研究成果，论文题目为“Accelerated dryland expansion under climate change”。

论文指出，如果全球温室气体排放量持续增加，全球干旱半干旱区面积将会加速扩张，到21世纪末将占全球陆地表面的50%以上。其中，全球干旱半干旱区扩张面积的四分之三将发生在发展中国家，干旱半干旱区扩张将使发展中国家面临土地进一步退化的风险，并加剧其贫穷程度。

干旱半干旱区是指降水不能补偿地表蒸发和植被蒸腾的区域。目前，干旱半干旱区约占全球陆地表面积的40%，受气候变化和人类活动的影响，干旱半干旱区将会继续扩张。

已有研究表明目前多数气候系统模式不能较好地模拟全球干旱半干旱区面积扩张程度。黄建平教授及其团队通过对比过去近60年的观测数据与气候系统模式模拟结果，证实气候系统模式明显低估了全球的干旱演变速率。进而利用历史观测数据对气候系统模式模拟结果进行了订正，使其能够更好地反映全球干旱半干旱区面积的变化。订正后的模式数据被用于预测未来中等排放情景（RCP4.5）和高排放情景（RCP8.5）下干旱半干旱区面积变化，发现在高排放情景下，21世纪末干旱半干旱区面积相比1961-1990年气候态的面积将增加23%，而78%的干旱半干旱区面积的扩张将发生在发展中国家。研究还表明干旱半干旱区的增温趋势显著高于湿润区，气候变暖、干旱加剧和人口增长的共同作用将增大发展中国家发生荒漠化的风险，从而进一步扩大全球经济发展的区域差异。这项研究加强了人类对温室气体减排和全球荒漠化防治紧迫性的认识。（记者薛朝华）

附：Nature英文报道材料原文

Climate Change: Developing countries to bear brunt of expanding drylands

Drylands could cover more than half of the global land surface by 2100 if global emissions continue to rise, reports a paper published online in Nature Climate Change. The study suggests that this will have a disproportionate effect on developing countries, where over three-quarters of the dryland expansion is projected to occur, and could exacerbate poverty levels and land degradation.

Drylands are regions where precipitation is offset by evaporation from surfaces and plant leaves. They currently cover approximately 40% of global land surface and are expected to increase in size due to climate change and human activities, such as urbanization and population growth.

Jianping Huang and colleagues compare historical observational data (1948–2005) to global climate model simulation data and find that the climate models underestimate global drying trends. They then use the observational data to correct the model projections and investigate change in dryland coverage under moderate and high emissions scenarios. Under a high emissions scenario, the authors find the land surface area that drylands cover will increase by 23% by 2100 (compared to baseline dryland coverage from 1961–1990), with 56% of global land surface covered. They find that 78% of this expansion will occur in developing countries.

The authors observe greater warming trends over dryland regions than humid regions, and conclude that the combination of temperature and aridity increases with population growth in developing countries will amplify the risk of further dryland expansion.