作者：Kan, F., Lian, X., Xu, H., Tang, S., Cui, J., Huntingford, C., Sun, M., Li, X. & Piao, S.

Forestation is a pivotal nature-based solution for mitigating global warming, yet its unintended hydrological outcomes and associated geospatial patterns remain understudied. Here, we combine land-atmosphere coupled models with the Budyko framework to show that forest-atmosphere feedbacks dominate a latitudinal divergence in runoff responses induced by global potential forestation, with increases in tropical regions but declines in boreal regions. In tropical regions, substantial precipitation gains due to intensified upward moisture transport overwhelm the negative effects of forest-driven evapotranspiration (ET) enhancement. Conversely, in boreal regions, limited precipitation gains are insufficient tooffset enhanced evaporative loss, driven by increased atmospheric demand due to elevated surface net radiation. The negative effects of direct forest expansion vary along the dryness gradient, with peak impacts in energy-water transitional regions. Our study highlights the necessity to incorporate hydrological considerations into carbon- or temperature-focused afforestation planning, and caution afforestation at high-latitudes where new forests may exacerbate water scarcity.

植树造林是缓解全球变暖至关重要的基于自然的解决方案，但其非预期的水文效应及相关地理空间格局仍缺乏深入研究。本研究将陆气耦合模型与布迪科框架相结合，揭示森林-大气反馈作用主导了全球潜在植树造林引发的径流响应纬度差异：热带地区径流增加，而寒温带地区径流减少。在热带地区，水汽向上输送增强带来的显著降水增益，超过了森林导致的蒸散发增强所产生的负面影响。相反，在寒温带地区，有限的降水增加不足以抵消因地表净辐射升高、大气需求提升所驱动的蒸散发损失加剧。森林直接扩张的负面影响随干旱度梯度发生变化，在能量-水分过渡区域影响达到峰值。本研究强调，在以碳或温度为核心的造林规划中必须纳入水文因素，并警示在高纬度地区开展造林可能加剧水资源短缺。

（来源：Nature communications  2026  DOI: 10.1038/s41467-026-68945-9）