ALBERT

Beschreibung: China has promoted its vegetation cover and terrestrial carbon sink through ecological restorations since the end of the 20th century. However, the temporal variation in vegetation carbon sequestration remains unclear, and the relative effects of climate change and human efforts are under debate. By integrating remote sensing and machine learning approaches into modelling, we explored the biological and physical pathways by which both climate change and human activities (e.g., ecological restoration, cropland expansion, and urbanization) have altered the Chinese terrestrial ecosystem, including the vegetation cover, surface heat fluxes, water flux and finally, vegetation carbon sequestration (i.e., gross and net primary production, GPP and NPP). During 2001~2018, GPP in China increased significantly at a rate of 49.1~53.1 TgC/yr2, and the climatic and anthropogenic contributions to GPP gains were comparable (48%~56% vs. 44%~52%). Spatially, afforestation dominated the forest cover expansions in the farming-pastoral ecotone in northern China, the Loess Plateau and the southwest karst region, while climate change promoted vegetation cover in most parts of southeastern China. Meanwhile, the NPP trend (22.4~24.9 TgC/yr2) during 2001~2018 was highly attributed to human disturbances (71%~81%), particularly in southern, eastern and northeastern China. The increases in both GPP and NPP both accelerated after 2010. This is because that over 2001~2010, the anthropogenic NPP gains were generally offset by the negative climatic impact in southern China. However, after 2010, the climatic influence reversed, becoming positive, thus magnifying the positive impact of ecological restoration.