Large scale investment in coastal protection is cost-efficient for 90 percent of today’s global floodplain population. This is the result of a global scale cost-benefit analysis of large-scale coastal protection performed by researchers from Global Climate Forum and published in the journal Global Environmental Change.
“Sea-level rise is occurring in many areas of the world and supposed to continue and possibly accelerate during 21st century. Our study illustrates that large scale protection, as it is already implemented in the Netherlands and the North of Germany, is generally economically efficient for densely populated coastal areas” explains lead author Daniel Lincke from the Global Climate Forum (GCF). “This holds true for a wide range of possible future sea-level rise scenarios (30cm – 190cm in 2100), a wide range of scenarios for social and economic development (from a poor and overpopulated world to a rich and sustainable managed world) and varying assumption on intergenerational climate change cost sharing. ”
The scientists conducted local cost-benefit analysis of coastal protection for over 12,000 coastal segments covering the complete coastline of the world. For each analysis 125 combinations of sea-level rise, socio-economic development and intergenerational climate change cost sharing scenarios have been considered. While only for 13 percent of the global coastline it was found that, under every scenario combination considered, investment in coastal protection costs less then the damages resulting from not protecting the coast, this small fraction of the global coastline accounts for 90 percent of today’s global floodplain population and for 96 percent of today’s global floodplain assets. Opposite that for 65 percent of the global coastline covering only 0.2 percent of global floodplain population and 0.2 percent of global floodplain assets investment in coastal protection costs more then the damages resulting from not protecting the coast under every scenario combination considered.
“Our results shows that the majority of coastal inhabitants lives in densely-populated and urban coastal areas, and is likely to (continue to) protect itself even under high-end sea-level rise. This is due to the high benefit-cost ratios of coastal protection in these areas. On the other hand, poorer rural areas will struggle to maintain safe human settlements and are likely to eventually retreat from the coast” adds co-author Jochen Hinkel from GCF. “Nevertheless, our study shows that there is a considerable opportunity to bridge the 21st century coastal adaptation finance gap for a large part of the world’s coastal population.”
Article: Daniel Lincke, Jochen Hinkel (2018): Economically robust protection against 21st century sea-level rise. Global Environmental Change 51, July 2018, Pages 67–73.