Humans increasingly settling in high-risk flood zones, study warns

BANGKOK: Humans are increasingly settling in areas highly exposed to dangerous flooding, a study warned on Wednesday, with China helping drive the rise in risky urban expansion into exposed areas.

The research, led by a World Bank economist, warns that settlement growth in flood zones has vastly outpaced growth in safe areas since 1985.

“In a time when human settlements should be adapting to climate change, many countries are actually rapidly increasing their exposure to floods,” author Jun Rentschler told AFP.

The study analysed 30 years of satellite imagery tracking the expansion of human settlement globally, along with flood maps.

While past studies have tended to focus on a particular region or type of flooding, the new research looked worldwide at coastal, rainfall and river flooding risks.

It found that by 2015, 20 percent of all settlement areas were in zones with medium or higher flood risks, up from 17.9 percent three decades earlier.

The percentage rise might not seem substantial, but it represents an enormous area because of how quickly human settlement has expanded globally since 1985.

About 76,400 square kilometres of human settlement -- about 48 times the size of greater London -- now faces flooding of more than half a metre, Rentschler said.

“These expanding settlements in high-hazard areas lock in flood exposure, as well as future losses and the need for mounting flood-protection investments,” the paper published in Nature warns.

East Asia and the Pacific region are among the most exposed, driven particularly by urban expansion in China, as well as Vietnam and Bangladesh.