Impacts of anthropogenic warming and uneven regional socio-economic development on global river flood risk

Abstract Employing a multi-model framework, we estimate the impacts of contrasting warming levels and uneven regional socio-economic development on area, population and gross domestic product (GDP) exposures to flood magnitude and variability in global Flood-Affected Regions (FARs). These exposures to flood variability show persistent increases in FARs, but to flood magnitude only in East and South Asia. Globally, the increases in these exposures are not projected in moderate but extreme floods. Specifically, the areal exposure would be decreased (increased) by 1.8%/℃ (1.9%/℃) for moderate (extreme) floods; the reduced population exposure to extreme floods can be three times higher than that to moderate floods when limiting 2 ℃ to 1.5 ℃ warming. Rapid regional economic growth of East and South Asia (whose GDP accounts for 9.8% of FARs in year 2000 to 18.5% in year 2025) would shift global GDP exposure from a decrease of 2.5%/℃ to an increase of 1.7%/℃.