Prospects for the potential carbon sink effects of afforestation to enhance weathering in China

The carbon sink effect of afforestation is key to mitigating current global warming. China’s planted forest area accounts for more than a quarter of the global afforestation efforts and has made a prominent contribution to carbon sequestration. Previously, afforestation as a carbon sink was primarily evaluated in terms of the biomass carbon pool and soil organic carbon pool. Plants play a significant role in enhancing the chemical weathering of rocks and minerals, which can lead to more CO₂ consumption. However, role of plants in enhancing chemical weathering and contributing to CO₂ removal has not been considered when calculating the artificial sink. This paper reviews relevant studies on the carbon sinks from weathering and forest biomass in China and synthesizes the research on how plants affecting weathering in natural ecosystems. Based on this, we estimate the atmospheric CO₂ consumption from afforestation-enhanced weathering in China. If afforestation increases the natural weathering rate by a factor of four on average, the national carbon sink through weathering could increase by 33 %. This increase in carbon sink capacity amounts to 35 million tonnes CO₂/y and represents ∼1/6 of China’s afforestation biomass carbon sink during 2014–2018. The significant contribution underscores the need for further comprehensive research into the carbon sink effect of afforestation-enhanced weathering in the future. Understanding how afforestation, global warming, and other anthropogenic activities interact to affect weathering will provide insights to accurately evaluate the role of large-scale afforestation in China’s efforts to meet its “dual-carbon” goals and mitigate global warming.