Climate Warming Benefits Plant Growth but Not Net Carbon Uptake: Simulation of Alaska Tundra and Needle Leaf Forest Using LPJ-GUESS

• Published in: Land
• Main Authors: Cui Liu, Chuanhua Li, Liangliang Li
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2024
• Subjects: climate warming; carbon uptake; LPJ-GUESS; Alaska tundra; Agriculture; S; Tundra; Alaska
• Online Access: https://doi.org/10.3390/land13050632; https://doaj.org/article/05420aa340ec42719f1790340d9c690d

Climate warming significantly impacts Arctic vegetation, yet its future role as a carbon sink or source is unclear. We analyzed vegetation growth and carbon exchange in Alaska’s tundra and needle leaf forests using the LPJ-GUESS model. The accuracy of the model is verified using linear regression of the measured data from 2004 to 2008, and the results are significantly correlated, which proves that the model is reliable, with R 2 values of 0.51 and 0.46, respectively, for net ecosystem carbon exchange (NEE) at the tundra and needle leaf forest sites, and RMSE values of 22.85 and 23.40 gC/m 2 /yr for the tundra and needle forest sites, respectively. For the gross primary production (GPP), the R 2 values were 0.66 and 0.85, and the RMSE values were 39.25 and 43.75 gC/m 2 /yr at the tundra and needle leaf forest sites, respectively. We simulated vegetation carbon exchanges for 1992–2014 and projected future exchanges for 2020–2100 using climate variables. Under SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios, GPP values increase with higher emissions, while the NEE showed great fluctuations without significant differences among the three pathways. Our results showed although climate warming can benefit vegetation growth, net carbon assimilation by vegetation may not increase accordingly in the future.