Coastal Flooding Could Affect 600 Million People Each Year

A study published in PLOS this week suggests that by the year 2100, 600 million people could be affected by coastal flooding each year. Though the global costs from storm surges are already high (between $10 and $40 billion per year) those figures could rise to $100,000 billion per year if precautions are not taken. Cities in Africa and Asia are thought to be most at risk, with large coastal metropolitan areas such as Shanghai, Manila and Lagos particularly vulnerable.

This study, led by Global Climate Forum, a Berlin-based think tank, represents the first comprehensive global simulation of its kind, combining four different climate models with three land-ice scenarios. It predicted a global mean sea-level rise of between 25 and 123 cm over the course of the 21st century, leading the authors to recommend urgent investment in coastal protection measures such as building or raising dikes. The lead author, Jochen Hinkel, points out that ‘poor countries and heavily impacted small-island states are not able to make the necessary investments alone. They need international support’. Coastal damage is not only an issue for developing countries, however, and the UK predicts that it will have to spend an extra £500m over the next four years to prepare for increased risk of flooding brought by climate change.

The study predicts that global annual investment of $12-71 billion will be needed by 2100 to maintain a network of dikes – while this represents a huge sum, it is substantially less than the cost of doing nothing. The hardest hit areas may be coastal developing nations, but this is by no means an isolated problem; the authors warn that concentrated international protection efforts must be enacted now to prevent future damage.