Storm surges threaten coastal regions

wikipedia / Alvesgaspar (CC BY-SA 3.0)
wikipedia / Alvesgaspar (CC BY-SA 3.0)

As an international team of researchers including Benjamin Marzeion from the Universitiy of Innsbruck reports, climate change and sea-level rise may cause trillions in damage to world’s coasts. Coastal regions have to adapt to sea-level rise soon. Prompt action is needed most in Asia and Africa.

Coastal regions may face massive increases in damages from storm surge flooding over the course of the 21st century. According to a new study published in the Proceedings of the National Academy of Sciences, global average storm surge damages could increase from about 10-40 billion USD per year today to up to 100,000 billion USD per year by the end of century, if no adaptation action is taken. The study lead by the Berlin-based think-tank Global Climate Forum (GCF) presents, for the first time, comprehensive global simulation results on future storm surge damages to buildings and infrastructure. Drastic increases in these damages are expected, on one hand, due to rising sea-levels and, on the other hand, due to population and economic growth. Asia and Africa may be particularly hard hit because of their rapidly growing coastal mega-cities, such as Shanghai, Manila or Lagos.

Year 2100: 5 percent of the global population could be affected

"If we ignore this problem, the consequences will be dramatic," explained Jochen Hinkel from GCF and the study’s lead author. In 2100, up to 600 million people (around 5 percent of the global population) could be affected by coastal flooding if no adaptation measures are put in place. "Countries need to take action and invest in coastal protection measures, such as building or raising dikes, amongst other options," urged Hinkel. With such protection measures, the projected damages could be reduced to below 80 billion USD per year during the 21st century. The researchers found that investments level of 10 to 70 billion USD per year could achieve such a reduction. Prompt action is needed most in Asia and Africa, where today large parts of the population are already affected by storm surge flooding.

Short-term interests dominate

"If we do not reduce greenhouse gases swiftly and substantially, some regions will have to seriously consider relocating significant numbers of people in the longer run," explained Hinkel. Yet regardless of how much sea-level rise climate change brings, careful long-term regional and urban planning can ensure that development in high-risk flood zones is avoided. This long-term perspective is however a challenge to bring about, as coastal development tends to be dominated by short-term interests of, for example, real-estate and tourism companies, which prefer to build directly at the waterfront.

Coastal flood damage and adaptation cost under 21st century sea-level rise. Hinkel, J., D. Lincke, A. T. Vafeidis, M. Perrette, R. J. Nicholls, R. S. J. Tol, B. Marzeion, X. Fettweis, C. Ionescu, and A. Levermann. Proceedings of the National Academy of Sciences 2014