Mumbai: Excess rains triggered the tragic floods in Kerala but there could be another threat: coastal flooding. Across the world, climate change is causing sea levels to rise which makes coastal areas such as Kerala vulnerable to flooding and other extreme events.

Madhavan Rajeevan, secretary, Ministry of Earth Sciences, warned recently that the rising temperatures in the Arabian sea has made states such as Kerala and Karnataka increasingly vulnerable to cyclones, and he is not alone in expressing such concerns. A new National Bureau of Economic Research (NBER) working paper by Klaus Desmet and others suggests that coastal flooding will disrupt the global economy, causing huge shifts in economic activity. As sea levels rise, low-lying land areas and small islands could shrink due to flooding and coastal erosion, forcing large-scale migration inland.

The authors estimate that by 2200, 1.46% of the world population will be displaced and move to inland regions. This shift will be difficult and costly, given the significant institutional, economic and natural barriers. As per the study, under a scenario of moderate greenhouse gas emissions, permanent flooding could reduce global real GDP by an average of 0.19% in present value terms and economic welfare by 0.24% as people move to places with less attractive amenities. Unsurprisingly, losses in many coastal localities will be of a greater magnitude, with large coastal cities such as Amsterdam, Bangkok and Ho Chi Minh City hit the hardest. In fact, some of these costs have already emerged. A report by the non-profit First Street Foundation says housing values in New York, New Jersey and Connecticut dropped $6.7 billion from 2005 to 2017 due to flooding related to rise in sea level. For India, the study simply reiterates the need for better flood management and improved flood-resilient infrastructure.

Also read: Evaluating the economic cost of coastal flooding