Objective Coastal wetlands, as critical ecological barriers at the land–sea interface, play irreplaceable roles in carbon sequestration, disaster risk reduction, and biodiversity conservation. However, the risk of “coastal squeeze” arising from the combined pressures of sea-level rise and human activities is becoming increasingly severe. There is an urgent need to investigate the spatiotemporal dynamics and adaptive responses of coastal wetlands at the national scale under different combinations of climate change and human activity scenarios.

Method Taking the coastal areas of China as the study area, we coupled the Sea Level Affecting Marshes Model (SLAMM) with the Patch-generating Land Use Simulation Model (PLUS) to simulate the spatial dynamics of coastal wetlands under combined scenarios of sea-level rise and land-use change. An adaptive assessment framework based on sensitivity, stability, and resilience was further developed to systematically evaluate the adaptive responses of Chinese coastal wetlands to the compound pressure of landward and seaward squeeze from 2020 to 2100.

Result (1) The combined effects of sea-level rise and land-use change were substantially greater than those driven by either factor alone. By 2100, the total area of coastal wetlands was projected to decline by 62.93%–73.94% across all combined scenarios, with estuaries and bays experiencing the most pronounced changes. (2) The overall level of adaptability of Chinese coastal wetlands was projected to remain low. By 2100, areas with extremely low and low adaptability were expected to account for 94.96%–96.51%, whereas areas with moderate to high adaptability were primarily concentrated in buffer zones around major river mouths. (3) The combination of the RCP4.5 climate scenario and ecological protection-oriented land-use strategy (RCP4.5-EP) performed better than the other combined scenarios over the long term, effectively maintaining coastal wetland area and relatively high levels of adaptability. (4) Under the RCP4.5-EP scenario, the proportions of typical coastal wetland types exhibiting moderate to high adaptability in 2100 followed the order mangroves (19.50%) > salt marshes (6.25%) > unvegetated tidal flats (4.43%). Adaptability of mangroves was primarily driven by resilience, whereas stability was the dominant component of adaptability for salt marshes and unvegetated tidal flats.

Conclusion Compound land–sea pressures not only cause substantial losses of coastal wetland area but also reshape their spatial patterns of adaptability, posing significant threats to coastal ecological security and territorial spatial security. Under the synergistic effects of relatively low climate-change pressure and ecological protection policies, coastal wetlands exhibit stronger spatial adaptability. Reserving sufficient landward migration space and implementing zonal and wetland-type-specific restoration measures can effectively mitigate coastal squeeze and enhance the long-term adaptive capacity and sustainability of Chinese coastal wetlands under the combined impacts of climate change and human activities.