Over two-thirds of terrestrial carbon is stored belowground, and a significant amount of the atmospheric CO₂ assimilated by plants is respired by roots and microbes in soils. Soil respiration (R_s), consisting of root respiration and microbial respiration, is the largest flux of CO₂ from terrestrial ecosystems to the atmosphere. 

R_s change can be affected by many factors, and climate factors, e.g., air temperature and precipitation, have been commonly investigated due to their direct or indirect effects on R_s metabolism. Land-cover change can also affect R_s by changing vegetation structure, plant species composition, and soil properties. 

However, few studies have comprehensively considered both climate and land-cover change effects on the spatial and temporal variations in global R_s. 

A research team led by Prof. NIU Zheng from the State Key Laboratory of Remote Sensing Sciences, Aerospace Information Research Institute (AIR) of the Chinese Academy of Sciences (CAS), and their cooperators proposed a remote-sensing driven model to estimate global R_s and analyzed its relationship with climate and land-cover. 

The study was published in Science Advances on Oct. 7. 

Previous studies suggested that climate change is the main factor leading to the change of global R_s. However, the researchers revealed that land-cover change played a more important role in regulating R_s changes in temperate and boreal regions during 2000-2014. Significant changes in R_s occurred more frequently in areas with significant changes in short vegetation cover than in areas with significant climate change. 

These findings contribute to our understanding of global R_s patterns and highlight the importance of land-cover change in driving global and regional R_s changes. 

The study was supported by the National Key Research and Development Program of China, the Strategic Priority Research Program of the Chinese Academy of Sciences, and the National Natural Science Foundation of China.