Key Laboratory of Digital Earth Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China; International Research Center of Big Data for Sustainable Development Goals, Beijing 100094, China.
Key Laboratory of Digital Earth Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China; International Research Center of Big Data for Sustainable Development Goals, Beijing 100094, China.
Sci Total Environ. 2023 May 1;871:162092. doi: 10.1016/j.scitotenv.2023.162092. Epub 2023 Feb 11.
China has experienced a rapid expansion of human settlement in both urban and rural areas over the past three decades. Regarding the impacts on carbon storage, previous studies that only focus on certain ecosystems cannot reflect urban-rural disparities, resulting in the carbon storage changes in human settlement remaining unknown. In this study, we aimed to explore China's urban-rural disparities in human settlement expansion and direct impacts on carbon storage by using the big Earth data technology. The results showed that from 1990 to 2018, the total amount of China's human settlement expansion reached 175,703.80 km, and the inner-city, peri-urban, and rural components accounted for 21.00 %, 20.18 %, and 58.82 %, respectively. Along with the general tendency of impervious surface area (ISA) growth, there was more soil organic carbon (SOC) (1254.33 TgC) being sealed beneath ISA (0-100 cm depth), compared to a huge reduction in vegetation biomass carbon (VBC) (91.44 TgC) during the study period. The results further indicated that the change density of either VBC or SOC presented a slightly rising trend along the urban-rural gradient, due to the increasingly common encroachment on vegetation and soil types with higher carbon content. We also found that socioeconomic drivers had a greater influence in urban areas than rural areas, and the related correlation exhibited a descending trajectory in both urban and rural areas. There is thus an urgent need to preserve lands with abundant carbon storage and contain the waste of land resources in rural areas. All stakeholders should pay more attention to concerted and targeted regulation policies for well-planned and eco-friendly human settlement expansion such as enhancing rural land use efficiency and promoting large-scale afforestation and continuous urban greening, which will be critical not only for guiding sustainable urbanization all over China but also for mitigating climate change for the entire world.
中国在过去三十年中经历了城市和农村地区人类住区的快速扩张。关于对碳储存的影响，以前仅关注某些生态系统的研究无法反映城乡差异，导致人类住区扩张的碳储存变化仍不清楚。在这项研究中，我们旨在利用大地球数据技术探索中国城乡人类住区扩张的差异及其对碳储存的直接影响。结果表明，1990 年至 2018 年，中国人类住区扩张总量达到 175703.80 公里，其中内城、近郊和农村部分分别占 21.00%、20.18%和 58.82%。随着不透水面面积（ISA）增长的总体趋势，在研究期间，有更多的土壤有机碳（SOC）（1254.33 TgC）被封存在 ISA（0-100 cm 深度）下，而植被生物量碳（VBC）（91.44 TgC）却大量减少。结果进一步表明，由于植被和土壤类型的不断侵占，VBC 或 SOC 的变化密度沿城乡梯度呈现出略微上升的趋势，这些土壤类型具有更高的碳含量。我们还发现，社会经济驱动因素在城市地区的影响大于农村地区，而相关相关性在城乡地区均呈下降趋势。因此，迫切需要保护具有丰富碳储存的土地，并遏制农村地区土地资源的浪费。所有利益相关者都应更加关注城乡协同和有针对性的调控政策，以实现规划合理和生态友好的人类住区扩张，例如提高农村土地利用效率、促进大规模造林和持续的城市绿化，这不仅对于指导全国可持续城市化至关重要，对于缓解全球气候变化也至关重要。
