Afforestation is gaining popularity as a climate mitigation policy in many countries, including high latitude regions such as Norway. However, the impacts of afforestation on local‐to‐regional climate is poorly understood. This study uses the Weather Research and Forecasting model to investigate the biogeophysical impacts of different forestry scenarios on the local‐to‐regional climate of Norway. The forestry scenarios considered are the conversion of open spaces to either evergreen forest by active afforestation or to mixed forest by natural succession. Results show both forestry scenarios lead to additional warming of surface temperatures in winter and spring (between 1.0°C and 1.5°C) and cooling in summer (between −1.6°C and −1.3°C). A temperature decomposition analysis shows that the warming in winter and spring is driven by surface albedo changes while summer cooling is driven by changes in sensible heat fluxes for afforestation and surface albedo for natural succession. Maximum 2 m air temperature increases considerably in spring in both forestry scenarios (∼0.8°C to 1.0°C). Analysis of precipitation, multiple climate indices and extremes, reveal little or no response to the different forestry scenarios. The largest societally relevant response to the forestry scenarios is the partial mitigation of the reduction in snow days expected from global warming by 10–20 days. This suggests that implementing current afforestation policies for climate mitigation in Norway may adversely exacerbate some effects of global warming locally while mitigating others. As such, the impacts of afforestation on the local‐to‐regional climate at high latitudes are complex and cannot support or dismiss afforestation as a climate mitigation policy.

中文翻译：

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复杂地形下高纬度准理想化未来土地覆盖情景的影响

在许多国家，包括挪威等高纬度地区，绿化作为减缓气候变化的政策正日益普及。但是，人们对造林对地方到区域气候的影响知之甚少。本研究使用天气研究和预报模型来调查不同森林情景对挪威当地到区域气候的生物地球物理影响。所考虑的林业情景是，通过主动造林将休憩用地转变为常绿森林，或者通过自然演替将休耕地转变为混合森林。结果表明，两种林业方案都导致冬季和春季（1.0°C至1.5°C之间）的地表温度进一步升高以及夏季（-1.6°C至-1.3°C之间）的地表温度进一步升高。温度分解分析表明，冬季和春季的变暖是由地表反照率的变化驱动的，而夏季的降温是由造林中感热通量的变化和自然演替的地表反照率的变化驱动的。在两种林业情况下，春季最高2 m的空气温度都会大幅升高（约0.8°C至1.0°C）。对降水，多种气候指数和极端因素的分析表明，对不同林业情景的反应很少或没有反应。对林业情景最大的与社会相关的反应是部分缓解，这是由于全球变暖导致的降雪天数减少了10-20天。这表明在挪威实施当前的绿化政策以缓解气候变化可能会不利地加剧全球局部变暖的某些影响，同时减轻其他影响。因此，