Carbon sequestration in the desert

The desert ecosystems worldwide are vast and may play positive roles in promoting carbon neutrality, reducing carbon loss, and mitigating climate warming. However, due to the contradictions between different observation methods and the unclear internal driving mechanism, desert carbon sink has long been neglected and questioned after many years of research. Accurately determining the contribution of deserts to the global carbon cycle remains unclear, which limits the exploration of their potential for increased carbon sequestration. This review summarizes the current research and key scientific problems related to desert carbon sequestration and outlines the key future directions of desert carbon sequestration development. The key processes and three main driving mechanisms for controlling the carbon sink effect of shifting sand were first elucidated: heat driven, hydrothermal synergy, and soil properties. Based on this, we establish a scheme to estimate the CO₂ flux of shifting sand that considers both hydrothermal interactions and soil properties. According to this assessment, annual CO₂ net sequestration in the shifting sands of Taklimakan Desert is approximately 1.05 × 10⁻³ Pg, which will continue to decrease with climate change. Furthermore, the desertification prevention and control not only directly improve the regional ecological environment but also endow it with important significance in consolidating and enhancing the stability and capacity of carbon sinks in arid areas. This review effectively elucidates the mechanisms underlying desert carbon sequestration, improves carbon emission estimation in arid areas, and lays a foundation for accurately assessing the total carbon sequestration capacity of global deserts and their contribution to the carbon cycle.