14 January 2016

Global drivers of future river flood risk

ABSTRACT Understanding global future river flood risk is a prerequisite for the quantification of climate change impacts and planning effective adaptation strategies.Existing global flood risk projections fail to integrate the combined dynamics of expected socio-economic development and climate change. We present the first global future river flood risk projections that separate the impacts of climate change and socio-economic development. The projections are based on an ensemble of climate model outputs, socio-economic scenarios, and a state-of-the-art hydrologic river flood model combined with socio-economic impact models. Globally, absolute damage may increase by up to a factor of 20 by the end of the century without action. Countries in Southeast Asia face a severe increase in flood risk. Although climate change contributes significantly to the increase in risk in Southeast Asia,we show that it is dwarfed by the effect of socio-economic growth, even after normalization for gross domestic product (GDP) growth. African countries face a strong increase in risk mainly due to socio-economic change. However, when normalized to GDP, climate change becomes by far the strongest driver. Both high- and low-income countries may benefit greatly from investing in adaptation measures, for which our analysis provides a basis.

Hessel C.Winsemius, Jeroen C. J. H. Aerts, Ludovicus P. H. van Beek, Marc F. P. Bierkens, Arno Bouwman, Brenden Jongman, Jaap C. J. Kwadijk, Willem Ligtvoet, Paul L. Lucas, Detlef P. van Vuuren and Philip J.Ward ; Nature Climate Change | Advance Online Publication | www.nature.com/natureclimatechange, 21 December 2015 | DOI: 10.1038/NCLIMATE2893