Delin Fang

Limiting the global temperature rise in this century to 1.5 °C above preindustrial levels has become a critical challenge. One key pathway involves actions in the land sector. Forecasts of land cover/use maps can provide valuable insights for guiding such actions, but the reliability of maps strongly depends on the accuracy of the baseline land cover/use map. In this study, we selected an accurate land cover/use map—HIstoric Land Dynamics Assessment+ (HILDA+), harmonized with multiple historical land cover/use maps—as the baseline land cover/use map. Additionally, we selected a future scenario that aims to achieve the 1.5 °C target and takes into account nationally determined contributions (NDCs). This scenario assumes that all parties would adhere to their submitted NDCs. We forecasted land cover/use maps at a spatial resolution of 1 km from 2020 to 2100 at a 10-year interval in China by integrating the Global Change Analysis Model, the Land-N2N model, and HILDA + land cover/use maps. These maps provide scientific guidance to support land management in addressing climate crises.

The increasing prevalence of impervious surfaces coupled with intense rainfall has exacerbated urban waterlogging, nonpoint source pollution, and ecosystem degradation. Nature-based solutions (NbS) have emerged as effective strategies for urban stormwater management. This study proposes a four-objective simulation-optimization framework, integrating the Stormwater Management Model (SWMM) with the NSGA-II algorithm, to optimize NBS layouts while accounting for ecosystem service value (ESV). Six NbS scenarios were evaluated in a case study in Beijing, China. Results indicated that rain garden scenarios outperformed others in maximizing ESV, particularly through enhanced net carbon sequestration. Sensitivity analysis revealed that pollution control rate exhibited greater variability than runoff reduction rate, and achieving simultaneous improvements in these metrics often incurred higher costs and reduced ESV. The optimal solution achieved a 51.95% runoff reduction rate, 87.35% pollution control rate, an ESV of 2.78 × 10⁵ CNY, and a cost of 40.14 × 10⁶ CNY. This framework provides a robust reference for harmonizing cost-efficiency, water quality and quantity control, and ecosystem service enhancement in urban stormwater management.