Liu Xiangyang, Li Zhao-Liang, Li Yitao, Wu Hua, Zhou Chenghu, Si Menglin, Leng Pei, Duan Si-Bo, Yang Peng, Wu Wenbin, Tang Ronglin, Liu Meng, Shang Guo-Fei, Zhang Xia, Gao Maofang
State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China; State Key Laboratory of Resources and Environment Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
Sci Bull (Beijing). 2023 Nov 30;68(22):2849-2861. doi: 10.1016/j.scib.2023.09.046. Epub 2023 Oct 4.
Land cover changes (LCCs) affect surface temperatures at local scale through biophysical processes. However, previous observation-based studies mainly focused on the potential effects of virtual afforestation/deforestation using the space-for-time assumption, while the actual effects of all types of realistic LCCs are underexplored. Here, we adopted the space-and-time scheme and utilized extensive high-resolution (1-km) satellite observations to perform the first such assessment. We showed that, from 2006 to 2015, the average temperature in the areas with LCCs increased by 0.08 K globally, but varied significantly across latitudes, ranging from -0.05 to 0.18 K. Cropland expansions dominated summertime cooling effects in the northern mid-latitudes, whereas forest-related LCCs caused warming effects elsewhere. These effects accounted for up to 44.6% of overall concurrent warming, suggesting that LCC influences cannot be ignored. In addition, we revealed obvious asymmetries in the actual effects, i.e., LCCs with warming effects occurred more frequently, with stronger intensities, than LCCs with cooling effects. Even for the mutual changes between two covers in the same region, warming LCCs generally had larger magnitudes than their cooling counterparts due to asymmetric changes in transition fractions and driving variables. These novel findings, derived from the assessment of actual LCCs, provide more realistic implications for land management and climate adaptation policies.
土地覆盖变化（LCCs）通过生物物理过程在局部尺度上影响地表温度。然而，以往基于观测的研究主要关注利用空间换时间假设进行虚拟造林/毁林的潜在影响，而各类实际LCCs的实际影响尚未得到充分探索。在此，我们采用了时空方案，并利用大量高分辨率（1公里）卫星观测数据进行了首次此类评估。我们发现，从2006年到2015年，全球范围内发生LCCs的地区平均温度上升了0.08K，但在不同纬度地区差异显著，范围在-0.05至0.18K之间。农田扩张主导了北半球中纬度地区夏季的降温效应，而与森林相关的LCCs在其他地区则造成了升温效应。这些效应占同期总体变暖的比例高达44.6%，表明LCCs的影响不容忽视。此外，我们还揭示了实际影响中存在明显的不对称性，即具有升温效应的LCCs比具有降温效应的LCCs出现得更频繁、强度更大。即使对于同一地区两种覆盖类型之间的相互变化，由于转变比例和驱动变量的不对称变化，升温型LCCs的幅度通常也大于降温型LCCs。这些来自对实际LCCs评估的新发现，为土地管理和气候适应政策提供了更现实的启示。
