A large but transient carbon sink from urbanization and rural depopulation in China
A large but transient carbon sink from urbanization and rural depopulation in China
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DOI：
10.1038/s41893-021-00843-y
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发表时间：
2022-02
影响因子：
27.6
通讯作者：
Xiaoxin Zhang;M. Brandt;Xiaowei Tong;P. Ciais;Y. Yue;Xiangming Xiao;Wenmin Zhang;Kelin Wang
中科院分区：
文献类型：
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作者：
Xiaoxin Zhang;M. Brandt;Xiaowei Tong;P. Ciais;Y. Yue;Xiangming Xiao;Wenmin Zhang;Kelin Wang
近几十年来，中国经历了前所未有的城市化和农村人口减少，同时总人口大幅增加。通过使用卫星和人口数据集，我们在这里测试的假设，即城市化和碳中和并不相互排斥，可持续管理的城市化甚至可能是减少大气CO2的途径的一个组成部分。我们发现，尽管城市扩张在2002-2010年期间造成了-0.02 PgC的初始地上碳损失，但城市绿化在2002-2019年期间以+0.03 PgC的总体平衡补偿了这些原始损失。我们进一步表明，地上碳储量的最大增加是在距离农村住区中等距离（2-4公里）处观察到的，反映了对自然资源的压力减少。因此，在2002-2019年期间，经历人口减少（-1400万人/年）的农村地区与0.28 ± 0.05 PgC/年的广泛地上碳汇相吻合，而与此同时，耕地面积仅略有下降（4%）。然而，树木覆盖增长饱和限制了森林的碳清除能力，只有减少化石燃料燃烧产生的CO2排放才能实现碳中和目标。
China has experienced unprecedented urbanization and associated rural depopulation during recent decades alongside a massive increase in the total population. By using satellite and demographical datasets, we here test the hypothesis that urbanization and carbon neutrality are not mutually exclusive and that sustainably managed urbanization may even be an integral part of the pathway to reduce atmospheric CO2. We show that, although urban expansion caused an initial aboveground carbon loss of −0.02 PgC during 2002–2010, urban greening compensates these original losses with an overall balance of +0.03 PgC in urban areas during 2002–2019. We further show that a maximum increase in aboveground carbon stocks was observed at intermediate distances to rural settlements (2–4 km), reflecting the decreased pressure on natural resources. Consequently, rural areas experiencing depopulation (−14 million people yr−1) coincided with an extensive aboveground carbon sink of 0.28 ± 0.05 PgC yr−1during 2002–2019, while at the same time only a slight decline in cropland areas (4%) was observed. However, tree cover growth saturation limits the carbon removal capacity of forests and only a decrease in CO2emissions from fossil fuel burning will make the aim of carbon neutrality achievable.