How climate variables affect CO2 fluxes from the High Arctic Tundra vegetation?

Presentation at the ASSW 2025 - ICARP IV Conference, Boulder, CO (USA). Abstract: Terrestrial ecosystems regulate the carbon cycle, and therefore atmospheric CO2 and Earth climate. The Arctic plays a major role in this cycle, due to the large amount of carbon stored in Arctic soil and vegetation. During the Holocene, the tundra has been acting as a carbon sink, but it is not clear if the Arctic warming will turn it into a carbon source. Yet, data regarding Arctic CO2 fluxes are scarce and the modelling of their dynamics and fate is affected by large uncertainties. Aiming at investigating the tundra soil and vegetation dynamics under climate pressures, CNR established the Bayelva Critical Zone Observatory in Ny Ålesund, Svalbard, since 2019, equipped with an Eddy Covariance tower and flux chambers for measuring Gross Primary Productivity (GPP) and Ecosystem Respiration (ER) at ecosystem scale, and correlating such variables to climate and environmental parameters, vegetation types and functions, and phenology. We quantified the dependence of CO2 fluxes from a number of parameters at the local scale. We are proposing the creation of a network of pan-arctic observatories with different vegetation composition and climate features to generalize the CO2 fluxes modelling effort and provide a sound database as a benchmark for models at various scales, including their use for validating remote-sensing estimates that link climate and vegetation composition and phenology to CO2 fluxes. This will facilitate the identification of the main variables to be used in general vegetation models and allowing future projections of CO2 fluxes under different climate change scenarios in the Arctic tundra.