Climate change is forcing Asian cities to rethink their flood defences

IN NORTH JAKARTA, not far from a quayside where workers unload frozen mackerel, a derelict building stands a metre deep in murky water. The warehouse was flooded in 2007, after torrential rains and a tidal surge submerged half the city under nearly four metres of water, displacing half a million people and causing $550m in damage. The building has remained inundated and abandoned ever since—barring the hardy soul who seems to be camping on the first floor, aided by a rowing boat.

Floods have always plagued Jakarta, but in recent years they have become more severe. Many other cities in Asia are menaced by the same phenomenon. As the planet heats up, sea levels are rising. Heavy rainstorms are also becoming more frequent and tropical cyclones more intense. And Asia’s coastal cities are growing, even as the risk of flooding increases. The number of people living in flood plains in Asia is expected to more than double between 2000 and 2060, according to the Asian Development Bank (ADB). As cities grow, they exacerbate flood-risk by covering ground that would once have absorbed water with concrete and asphalt. The amount and value of the property at risk also grows. Thirteen of the 20 cities projected to have the biggest increases in annual losses caused by flooding between 2005 and 2050 are in Asia.