CO
2, one of the major greenhouse gases, doesn't distribute evenly around the globe. Spatial variation of CO
2 regulates climate system and carbon cycle through physiological effect and radiative forcing. Understanding its impact is therefore important for climate prediction and understanding changes in terrestrial carbon cycle. However, there is still great uncertainty about how this non-uniform spatial distribution of atmospheric CO
2 concentration affects carbon cycle of the Northern Hemisphere. Recently, Dr. PENG Jing from Prof. DAN Li's research team at CAS Key Lab of Regional Climate-Environment for East Asia (TEA), Institute of Atmospheric Physics, Chinese Academy of Sciences, conducted a systematic study on how the spatial distribution of atmospheric CO
2 concentration influences the carbon sink of terrestrial ecosystems.
In this work, Earth System Model (ESM) was used to estimate the carbon uptake in the mid–high latitudes from 2031 to 2060 under the SSP5-8.5 future emissions scenario. Results showed that, in the high latitudes, non-uniform CO2 led to a reduction in Net Ecosystem Production (NEP) by -0.1 Pg C yr-1. This mainly resulted from a 1.5-fold greater increase in soil respiration than in Net primary production (NPP). In the mid-latitudes, meanwhile, the decrease in carbon uptake was generally due to a two-fold greater decrease in NPP than soil respiration.
In addition, the decrease in precipitation was closely correlated with local carbon uptake, which could explain this decrease in NPP. "We also found that, in East Asia, changes in atmospheric circulation induced by the non-uniform CO2 might have reduced the amount of large-scale precipitation by -9 mm yr-1." said Peng, "This reduction was the primary contributor (98%) to the decrease in overall precipitation, possibly strengthening the limitation of water on plant growth, which would cause a decline in NEP."
Peng suggested that such spatical variation in CO2 concentrations should be assessed in ESM for possible impacts on local carbon uptake.
This study was recently published in the
Journal of Geophysical Research: Atmospheres. It was supported by the National Natural Science Foundation of China (42175142, 41975112, 42175013, 41965010 and 42141017) and the National Key Research and Development Program of China (2016YFA0602501).
Reference:
Peng, J., Dan, L., Ying, K., Xu, D., & Tang, X. (2022). Spatially varying in CO2 concentrations regulates carbon uptake in the Northern Hemisphere. Journal of Geophysical Research: Atmospheres, 127, e2022JD037732. https://doi.org/10.1029/2022JD037732
Media contact: Ms. LIN Zheng, jennylin@mail.iap.ac.cn
