《自然—气候变化》上的一项研究预测,考虑到未来气候变暖的情况,亚洲、非洲和南美洲部分地区的洪灾发生频率将大幅提高。但在全球某些地区,洪灾发生频率可能反而降低。这表明有必要针对洪灾加剧采取一些应对措施以及进一步引入一些策略来减缓温室气体排放。
政府间气候变化专业委员会(IPCC)最近的一项有关洪灾预测的特别报告称,由于“依据有限”,“总体来说,关于河流洪水变化的一些预测并没有什么把握”。事实上,到目前为止,几乎很少有研究采用了复杂模型来作出预测,而且没有科学家对未来变暖气候中的洪灾风险进行过评估。
Yukiko Hirabayashi等人根据11个气候模型的输入结果,呈现了本世纪末的全球洪灾发生风险。他们研究了洪灾的变化并评价了其连贯性和范围。据研究小组预测,东南亚、印度半岛、东非和安第斯山脉北部地区的洪灾发生频率将增加。而在欧洲北部和东部、安纳托利亚、中亚、北美洲中部和南美洲南部的许多地区洪灾发生频率将降低。
除了全球范围的分析,一些河流流域的出口也在模型中获得分析。在21世纪内,南亚、东南亚、大洋洲、非洲和亚欧大陆东北部的所有被研究到的河流的洪灾发生频率将会是上升的。研究人员还预测,在21世纪,许多河流每10到50年便会发生一次百年一遇的洪水。
研究人员警告,全球洪灾发生的增加依赖于气候变暖的程度,但洪灾发生的这种年度间变化可能意味着在气候显著变暖之前采取应对措施的必要性。他们强调,应该重点关注低纬度国家的应对和缓解措施,因为预计这些国家的洪灾发生率和人口都将增加。(生物谷Bioon.com)
生物谷推荐的英文摘要
Nature Climate Change DOI: doi:10.1038/nclimate1911
Global flood risk under climate change
Yukiko Hirabayashi,1 Roobavannan Mahendran,1 Sujan Koirala,1 Lisako Konoshima,1 Dai Yamazaki,2 Satoshi Watanabe,1 Hyungjun Kim3 & Shinjiro Kanae
A warmer climate would increase the risk of floods1. So far, only a few studies2, 3 have projected changes in floods on a global scale. None of these studies relied on multiple climate models. A few global studies4, 5 have started to estimate the exposure to flooding (population in potential inundation areas) as a proxy of risk, but none of them has estimated it in a warmer future climate. Here we present global flood risk for the end of this century based on the outputs of 11 climate models. A state-of-the-art global river routing model with an inundation scheme6 was employed to compute river discharge and inundation area. An ensemble of projections under a new high-concentration scenario7 demonstrates a large increase in flood frequency in Southeast Asia, Peninsular India, eastern Africa and the northern half of the Andes, with small uncertainty in the direction of change. In certain areas of the world, however, flood frequency is projected to decrease. Another larger ensemble of projections under four new concentration scenarios7 reveals that the global exposure to floods would increase depending on the degree of warming, but interannual variability of the exposure may imply the necessity of adaptation before significant warming.