Managing development choices is essential to reduce coastal flood risk in China

Policy brief Coastal adaptation https://doi.org/10.1038/s41558-025-02418-7 Managing development choices is essential to reduce coastal flood risk in China Yafei Wang, Yuxuan Ye, Robert J. Nicholls, Lennart Olsson, Detlef P. van Vuuren, Garry Peterson, Yao He, Manchun Li, Jie Fan & Murray Scown Future exposure to coastal flooding in China is driven more by growing populations and economic activity rather than by rising seas and intensifying storm surges. Policymakers must anticipate these multiple risk drivers to better inform spatial planning and development strategies and to ensure effective, sustainable coastal adaptation. based on Y. Wang et al. Nature Climate Change https://doi.org/10.1038/ s41558-025-02439-2 (2025). The policy problem Flood exposure and risk in China’s coastal zone is large and growing, driven by population and asset growth, human-induced land subsidence and climate-induced sea-level rise. Yet, existing development plans largely overlook how these interconnected drivers shape future flood risk, encouraging continued coastal expansion without integrating long-term adaptation into policy or planning. Such disconnection between development planning and risk governance leaves millions of people increasingly exposed and undermines the resilience of coastal communities and infrastructure. Understanding how different development trajectories interact with climate and subsidence dynamics is essential to inform effective, context-specific adaptation strategies and to clarify responsibilities across levels of government. While global action is critical to limit climate-induced sea-level rise, coordinated national, regional and local interventions are urgently needed in China to manage flood exposure, minimize subsidence and guide resilient coastal development. The findings We find that spatial development policies have a greater influence than sea-level rise on future flood exposure in China’s coastal zone. Under an aggressive economic development pathway, the gross domestic product and the population exposed to coastal flooding nearly doubles by 2100 compared with a strict ecological protection scenario — even when sea-level rise assumptions are held constant. This is largely due to land-use changes that concentrate assets in low-lying, high-risk zones. While extreme sea levels shape the extent of physical inundation, it is policy that determines who and what is at risk. These results highlight the critical role of development policy in managing compound climate risks, especially for fast-growing coastal regions. While we account for the flood protection provided by current standards, our analysis does not capture future adaptive measures or the socioeconomic costs of protection and relocation, nature climate change Check for updates which may influence real-world outcomes and should be addressed in further research. The study We explore how coastal development policies, land subsidence and climate-driven sea-level rise combine to influence flood risk along China’s coast. We developed a set of scenarios to 2100 by integrating policy-driven land system changes with climate-based extreme sea-level-rise projections. Our approach incorporates key factors including land subsidence, tides, storm surges and existing coastal defences. Using a machine learning model, we produced detailed maps of land subsidence, improving on previous estimates, and projected future subsidence under different scenarios. To avoid overestimating flood exposure, we applied a physics-informed inundation model that considers the interaction of water flow and land elevation. This allowed us to evaluate possible impacts on critical coastal functions — population, food production, economic activity and ecosystems — under a wide range of possible futures. By integrating land system and sea-level-rise scenarios, we isolated the influence of development policies on flood exposure, independent of climate effects, thereby advancing regional and global assessments (Fig. 1). Yafei Wang 1,2,3,4 , Yuxuan Ye 1,2, Robert J. Nicholls 5,6, Lennart Olsson 3, Detlef P. van Vuuren 7,8, Garry Peterson 4, Yao He 1,2, Manchun Li9,10, Jie Fan 1,2 & Murray Scown 3,11 1 Key Laboratory of Regional Sustainable Development Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China. 2College of Resources Recommendations for policy • Integrate climate flood risk projections into national and subnational coastal development and spatial planning frameworks. • Use scenario-based assessments to guide land-use decisions in ecologically and economically sensitive coastal zones. • Improve and enforce coastal flood protection standards, particularly in areas currently below 1-in-100-year levels. • Refine and implement policies aimed at reducing the rate and risk of land subsidence in sensitive localities. • Develop adaptive regional and local planning that includes land system transitions and moves beyond protection-focused adaptation by exploring retreat, accommodation and ecosystem-based strategies. Volume 15 | October 2025 | 1033–1034 | 1033 Policy brief b Effect of climate mitigation for policy A Effects of alternative development pathways Effect of climate mitigation for policy B Policy scenario B c 1.4 4.0 3.0 2.5 2.0 0.4 Year Year f 0.9 0.8 0.7 0.6 0.5 2030 2040 2050 2060 2070 2080 2090 2100 2030 2040 2050 2060 2070 2080 2090 2100 Gross domestic product (× 108 yuan) 0.6 0.8 0.6 1.0 0.8 1.0 2030 2040 2050 2060 2070 2080 2090 2100 e 1.0 1.2 Year Aquaculture (× 107 metric tons) Grain production (× 107 metric tons) d 3.5 1.5 Time Ecosystem service value (× 107 yuan) Policy scenario A Population (× 107) Exposure a 2030 2040 2050 2060 2070 2080 2090 2100 Year 8 6 4 2030 2040 2050 2060 2070 2080 2090 2100 Year Future development pathways Economic development oriented Middle road Upper bound Ecological protection oriented Lower bound Median Fig. 1 | Effects of development policy pathways and climate change scenarios on flood exposure of people and assets in China’s coastal zone until 2100. a, Conceptual framework illustrating how alternative development pathways (for example, Policy scenario A versus Policy scenario B) and varying levels of climate mitigation (shaded areas) shape exposure trajectories over time. b–f, Projected exposure of five key indicators from 2030 to 2100 under three development pathways: economic development oriented (orange), middle road (brown) and ecological protection oriented (blue). Indicators include population (b), ecosystem service value (c), grain production (d), aquaculture production (e) and gross domestic product (f). Solid lines denote median projections, while shaded bars indicate the range across climate scenarios (upper and lower bounds), reflecting the role of climate mitigation as conceptualized in a. Figure adapted from Y. Wang et al. Nat. Clim. Change https://doi. (...truncated)