The world’s second most populous country was the biggest contributor to the global expansion of high-hazard settlements, the study found.
It was conducted by researchers from the World Bank, Swiss data consultancy MindEarth and the University of the Aegean in Greece. Their findings were published in the peer-reviewed journal Nature last week.
Lead author Jun Rentschler, a senior economist at the World Bank, said many countries were rapidly increasing their exposure to floods, despite the need to adapt to climate change as it intensifies flooding disasters worldwide.
Rentschler, who focuses on the intersection of climate change and sustainable, resilient development, said China’s “extraordinary growth over the past decades” had fuelled urbanisation.
“Like in many countries, the industrial and economic hubs that have grown the fastest are located in coastal regions, which offer access to trade routes and resources but are also exposed to high flood risks,” he said.
While “the benefits of developing in flood-prone areas may be worth the risk”, he said it was important to be prepared for floods.
“This requires the ability to forecast floods, invest in early warning systems and evacuation protocols, and to be ready to support the population if it needs to recover and rebuild after a flood,” he said.
Across East Asia, the expansion of high-hazard settlements has outpaced that of flood-safe settlements by 60 per cent, the study found.
Rentschler said one reason was a scarcity of land. When safe land is already occupied, new development often occurs in areas that were previously avoided, which could be because of flood risks.
“In many fast-growing urban centres in the developing world, new arrivals in a city often settle in flood-prone informal settlements, and once settled it becomes difficult to reverse such risky urban expansion,” he said.
Some countries chose to rapidly expand port cities in flood-prone coastal areas for tourism or other economic opportunities, but some places developed in dangerous zones because of a lack of data and information from proper risk assessments, according to Rentschler.
“Before reducing risks, countries need to stop increasing it,” he said, adding that “local authorities can actually do much more to protect people and prevent future climate change impacts”.
He said for places with high flood exposure, investments in disaster preparedness were crucial to mitigate losses, whereas areas with growing exposure needed urgent revision of land use and urbanisation plans.
“While land scarcity and geographic constraints may mean that settling in flood zones cannot always be avoided, flood protection systems and disaster preparedness measures can still support resilient socio-economic development,” he said.