Local decisions in China affect coastal flood exposure more than global sea-level rise

As climate change accelerates, much public attention has focused on how sea-level rise and extreme storm surges will affect coastal flood risk. Yet one critical factor is often overlooked: the role of coastal development choices and how they dynamically interact with land-use change, subsidence, and climate hazards.

The new study in Nature Climate Change shows that in China, coastal development policies could drive greater exposure to flooding than sea-level rise itself by 2100.

Home to hundreds of millions

China’s coast is home to hundreds of millions of people and a very large fraction of global manufacturing and trade infrastructure. Extreme tides and storm surges drive most of the flooding risk, while land subsidence, often worsened by human activity like groundwater pumping, makes the situation worse.

The new research shows that decisions taken today—on development priorities, land management, and adaptation strategies—will decisively shape the resilience of China’s coasts to 2100 and beyond. Disaster preparedness, ecosystem-based defenses like mangroves, better land-use planning, and tackling global change by reducing emissions are all essential for managing risk.

“These findings highlight that decisions made today—about development priorities, land management, and adaptation strategies—will shape the resilience of China’s coasts through 2100 and beyond, “ says main author Yafei Wang, Associate Professor at the Institute of Geographic Sciences and Natural Resources Research at the Chinese Academy of Sciences.

Coastal resilience

The researchers combined climate projections with detailed simulations of land system changes under different policies. They also incorporated high-resolution subsidence maps produced with machine learning, as well as tides, storm surges, and existing coastal defenses in a physics-informed inundation model. This comprehensive approach allowed them to evaluate potential impacts on population, food production, economic activity, and ecosystems, providing a nuanced picture of China’s coastal risks.

The results were striking: while sea-level rise determines the physical extent of inundation, policy decisions dictate who and what will be most exposed. Under an “ecological protection” pathway, farmland and wetlands are more exposed, whereas under rapid economic development, expanding cities and industrial zones bear the brunt.

By 2100, the share of coastal GDP exposed to flooding could nearly double depending on the policy trajectory—an effect larger than the difference between low- and high-end sea-level rise scenarios.

“Coastal resilience means discovering ways for people to live with water,” says Centre professor Garry Peterson. “Cities can be designed to work with water rather than against it. Designing parks and green spaces that safely flood during storms and then become vibrant public places in calmer times show how adaptation can create both resilience and more livable cities.”

Call for integrated strategies

The authors caution against relying too heavily on levees and seawalls, which can create a false sense of security and encourage riskier development—a phenomenon known as the “levee effect.” Instead, they call for integrated strategies: stricter land-use planning, tighter controls on land subsidence, ecosystem-based defenses such as mangroves, and, where needed, managed retreat.

“Spatial planning to avoid development in high-risk zones is essential,” states Murray Scown, associate senior lecturer at Lund University Centre for Sustainability Studies (LUCSUS). “Rapidly reducing carbon emissions is equally critical, to prevent sea-level rise from becoming the dominant risk factor beyond 2100—not just in China, but globally.”