By Staff Reporters

A group of Chinese scientists have recalculated the size of China's land carbon sink, with their findings recently published in Nature. The study reveals that earlier estimates—also published in Nature in 2020—had overestimated the country's carbon sequestration capacity.

▲ PHOTO: XINHUA

Using data from the Copernicus Atmosphere Monitoring Service (CAMS), the team found that after adjusting for lateral carbon flux, China’s average annual land carbon sink between 2010 and 2016 was approximately 920 million tons of CO₂.

However, if CO₂ concentration data from the Shangri-La Atmosphere Watch Station in Yunnan province were included in inversion calculations, the estimated sink could reach 2.57 billion tons of CO₂ per year.

To investigate this discrepancy, researchers conducted high-resolution atmospheric transport modeling to analyze the station’s observational footprint. They discovered that spring and autumn CO₂ levels at the site had been significantly underestimated in prior studies. Earlier models used the station’s data as representative for a broad grid area in coarse-resolution simulations, leading to an overestimation of carbon uptake in southwestern China.

The team also applied a bottom-up approach using national forest and ecosystem inventory data from the past decade. This analysis showed an annual increase in terrestrial carbon storage of 280 million tons of carbon—equivalent to 1.03 billion tons of CO₂—closely aligning with the revised top-down inversion results.

The authors of the original 2020 study acknowledged the new findings, noting that while systematic biases exist across different modeling approaches, China’s land ecosystems still constitute a significant carbon sink.

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Editor | SONG Ziyan

Supervisor| TIAN Xueke