Development policy affects coastal flood exposure in China more than sea-level rise

nature climate change Article https://doi.org/10.1038/s41558-025-02439-2 Development policy affects coastal flood exposure in China more than sea-level rise Received: 17 February 2025 Accepted: 21 August 2025 Yafei Wang 1,2,3,4 , Yuxuan Ye 1,2, Robert J. Nicholls 5,6, Lennart Olsson Detlef P. van Vuuren 7,8, Garry Peterson 4, Yao He 1,2, Manchun Li9,10, Jie Fan 1,2 & Murray Scown 3,11 , 3 Published online: 24 September 2025 Check for updates Effective coastal exposure assessments are crucial for adaptively managing threats from sea-level rise (SLR). Despite recent advances, global and regional assessments are constrained by omitting critical factors such as land-use change, failing to disaggregate potential impacts by land uses and oversimplifying land subsidence. Here we address these gaps by developing context-specific scenarios to 2100 based on a comprehensive analysis of Chinese coastal development policies. We integrate high-resolution simulations of population and land-system changes with inundation exposure assessments that incorporate SLR, land subsidence, tides and storm surges, offering a more nuanced understanding of coastal risks. Across our plausible set of downscaled scenarios of shared socioeconomic and representative concentration pathways, policy decisions have a bigger effect on what is exposed to coastal flooding until 2100 than does the magnitude of SLR. Hence, coastal policy decisions largely influence coastal risk and adaptation needs to 2100, demonstrating the necessity of appropriate policy design to manage coastal risks. Coastal zones are on the front line when it comes to facing the increasing threats associated with climate change1–3. Coastal scenario analysis and risk assessments are important tools for advancing knowledge and guiding policy—providing, for example, estimates of populations and assets exposed to flooding4,5 and weighing anticipated economic losses against costs of adaptation6. However, coastal risk is multifaceted. Climate change affects sea-level rise (SLR) and the frequency and intensity of storms, combining to raise extreme sea levels (ESLs) in certain areas7; land subsidence driven by human activity such as groundwater extraction increases relative SLR in populated coastal lowlands often at rates much higher than those caused by climate change alone5,8; and coastal development and adaptation actions determine who and what are exposed and vulnerable to flooding, salinization or erosion. So far, limited advances have been made in global and regional coastal inundation exposure assessments and management using the scenario frameworks of the shared socioeconomic and representative concentration pathways (SSPs and RCPs). They, for instance, mostly (1) do not disaggregate impacts on different land uses and sectors (see ref. 9 for recent advances in Europe); (2) do not consider all components driving exposure (see ref. 3); and (3) have coarse spatial resolution (see refs. 10,11 for recent improvements to the commonly applied dynamic and interactive vulnerability assessment (DIVA) modelling framework). Recent assessments for China have ignored the effects Key Laboratory of Regional Sustainable Development Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China. 2College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China. 3Lund University Centre for Sustainability Studies (LUCSUS), Lund University, Lund, Sweden. 4Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden. 5Tyndall Centre for Climate Change Research, University of East Anglia, Norwich, UK. 6School of Engineering, University of Southampton, Southampton, UK. 7 PBL Netherlands Environmental Assessment Agency, The Hague, the Netherlands. 8Copernicus Institute of Sustainable Development, Utrecht University, Utrecht, the Netherlands. 9School of Geography and Ocean Science, Nanjing University, Nanjing, China. 10Collaborative Innovation Center for the South Sea Studies, Nanjing University, Nanjing, China. 11Swedish Centre for Impacts of Climate Extremes (CLIMES), Lund University, Lund, Sweden. e-mail: ; 1 Nature Climate Change | Volume 15 | October 2025 | 1071–1077 1071 Article https://doi.org/10.1038/s41558-025-02439-2 a Lo w D MI ECON Low h Hig nd Grain production E x p o s u re o f lan d f u n c ti o n s Tide and surges er emission High Policy un ce rta in SL R High-e Population/GDP OL S B+T SU Ecosystem EC + Urban and industrial area nomy-oriented Eco Aquaculture Low-end Extreme sea-level rise SL R e ng ra dMi Agriculture ty Lower em iss ion inty rta ce un riented al-o gic o ol Ec High Land system projection Subsidence Sea-level rise Aquaculture production Water depth Ecosystem services Low b Exposure Low-end Mid-range High-end Exposure c SLR scenarios Policy scenario A ECOL high Policy scenarios High Effect of climate mitigation for policy A Effects of alternative development pathways ECOL low Middle road ECON low Policy scenario B ECON high Effect of climate mitigation for policy B Time Fig. 1 | Improved coastal exposure assessment framework covering several components. a, We combine land-system change affected by coastal development policies alongside mean SLR, land subsidence (SUB), and tides and storm surges (TS). b, We combine the effects of ECON, ECOL and MID policy scenarios with enhanced relative SLR scenarios spanning the broad set of SSPRCP scenarios and including land subsidence. c, We evaluate potential impacts to several land-system functions, as well as population and GDP, by considering potential flood exposure to different water depths over time under different scenarios. Policy scenarios have a median effect on exposure (solid lines), around which SLR scenarios create uncertainty (shaded bands). Similarly (though not illustrated), SLR scenarios have a median effect around which policy scenarios create uncertainty. The combined analysis reveals the sensitivity of exposure outcomes to both policy decisions and climatic trajectories. of land subsidence12,13 or have failed to consider in detail how land-use planning and development dynamics interact with SLR to affect coastal exposure8,10. Such omissions could result in underestimates of exposure and/or overemphasis on climate change and SLR as its main driver, leading to misjudgments in the urgency of adaptation and/or confusion as to which actors have agency and responsibility. Here we assess how Chinese coastal development plans interact with relative SLR and extreme events to determine exposure of several coastal zone functions across a range of scenarios. This is done by simulating land-system changes for the entire coastal zone of mainland China and Hainan for five development policy scenarios and combining this with estimates of land subsidence and ESLs across three SLR scenarios. For the land-use and population scenarios, (...truncated)