Coastal flood damage and adaptation costs investigated

02/04/2014 - Without increased coastal protection, between one and ten out of 200 people per year could be affected by flooding by the end ouf our century. In such a scenario of unmitigated climate change, the damages induced by sea-level rise without adaptive measure could be expected to be between 1.2 and 9.3 percent of economical activity. These are some results of a yet unprecedentedly broad analysis now published in the Proceedings of the National Academy of Sciences. Building dikes would cost substantial amounts of money – yet much less than the damages by flooding without protection, according to the analysis.
Coastal flood damage and adaptation costs investigated

“Our results highlight the importance of long-term coastal adaptation strategies – man-made seal-level rise is a reality we cannot afford to ignore,” says Anders Levermann from the Potsdam-Institute for Climate Impact Research. He initiated the analysis that Jochen Hinkel of the Global Climate Forum is the lead-author of. In many regions retreat from the coast inland is not an option, as a lot of infrastructure, thus hard-to-move capital, is located near the shore. The global costs of building and maintaining dikes are estimated by the authors to be between 12 and 71 billion US dollars per year.

Although increased coastal flood damages are amongst the most obvious aspects of climate change, so far few studies have assessed this impact globally and comprehensively. To fill this gap, the scientists used four different climate models, each combined with three land-ice scenarios, various datasets on topography, and five socio-economic scenarios. Hence, instead of seemingly precise numbers they provide ranges of what could be expected in the future, many of them being quite large. Still, this broad multi-model approach is likely providing the most accurate estimates to date.

"While coastal protection can reduce sea-level damages significantly, the corresponding adaptation costs get bigger and bigger the longer we wait with our mitigation efforts," Levermann warns. “Adaptation, as necessary as it is, by no means can be a substitute for reducing greenhouse-gas emissions."


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