Effects of Elevated Carbon Dioxide on vegetation in Tibetan Plateau

Fig. 1 Distribution of CO2 enrichment experiment site and sketch map of the experimental layout on the Tibetan Plateau. This Figure is from the study of Zhu et al.

At present, effects of climate change on the Tibetan Plateau, characterized mainly by elevated CO2, slightly increased precipitation and significant increased temperature (0.16 to 0.67°C decade-1 since the 1950s) (Kuang and Jiao, 2016) on plant growth, have already been concerned by scientists(Fu et al., 2018, Zhao et al., 2019). And as an important part of atmospheric change, elevated CO2 can improve primary productivity(Zhao et al., 2020, Kuzyakov et al., 2019) and has a critical impact on ecosystem biomass and species diversity on the Tibetan Plateau(Zhao et al., 2020, Zhu et al., 2020).

Free-Air CO2 Enrichment (FACE) experiments have confirmed that elevated CO2 can stimulates photosynthetic

carbon gain and primary production over the long term (Leakey et al., 2009). Zhao et al. held the first CO2 enrichment experiments on the Tibetan Plateau. By using empirical evidence, they assessed the response of plant biomass to elevated CO2. And they found that elevated CO2 significantly stimulated plant growth and increased the accumulation of carbon in biomass, but it had no effect on belowground biomass (table 1).

Table 1. Plant biomass, C concentrations of above and below tissues in response to elevated CO2. This table is from the study of Zhao et al.

Similar to the study of Zhao et al, based on a 6-yr field experiment in a grassland in Tibetan Plateau, Zhu et al. explored the effects of rising atmospheric CO2 concentration on aboveground biomass and species diversity (figure 1). And their study revealed that adding CO2 alone did not change total biomass or species diversity greatly. However when adding CO2 and N together, biomass and composition of the community altered significantly (figure 2) (Zhu et al., 2020).

Fig.2 Effects of nitrogen (N) addition and CO2 enrichment on aboveground biomass and species richness. This figure is from the study of Zhu et al.

Overall, according to the above studies, continuously rising CO2 has enhanced plant photosynthesis, increased net ecosystem productivity and altered community composition on the Tibetan Plateau. But studies also revealed that, on the plateau, this CO2 fertilization effect was limited by nitrogen availability (Kou et al., 2020, Zhu et al., 2020) and in the future, plant biomass may have a low growth potential.


I am very thankful to Wang Han whose very detailed comments helped to greatly improve the logic and quality of the blog and broadened my view on how to write a discussion and also thanks the suggestions from Han Wang, I. Colin Prentice and Sandy P. Harrison for our ongoing project about Tibetan Plateau leaf area index.


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ZHAO, G., LIANG, C., FENG, X., LIU, L., ZHU, J., CHEN, N., CHEN, Y., WANG, L. & ZHANG, Y. 2020. Elevated CO2 decreases soil carbon stability in Tibetan Plateau. Environmental Research Letters, 15.

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ZHU, J., ZHANG, Y., YANG, X., CHEN, N. & JIANG, L. 2020. Synergistic effects of nitrogen and CO2 enrichment on alpine grassland biomass and community structure. New Phytol.


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