Global drivers of future river flood risk

21-12-2015 | Publication

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.

New global river flood risk projections

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.

Flood risks increase factor 20, without action

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.

Climate change relevant driver

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.

The global flood risk model GLOFRIS has been used in various recent assessments, amongst others:

>PBL 2014. Towards a world of cities in 2050. An outlook on water-related challenges

>GWP/OECD 2015. Securing Water, Sustaining Growth

>World Bank 2015. Shock waves. Managing the impacts of climate change on poverty