Belowground ecosystem properties are likely one of the most important drivers of Arctic ecosystem response to climate change. At our first meeting during ASSW2020 we introduced the four themes and formed working
The Critical Zone (CZ) is the living skin of our planet, extending from the top of vegetation canopy through soil and groundwater to unweathered bedrock, and it represents the life-support system of terrestrial ecosystems. Currently, climate and land-use change, soil erosion and water/air pollution affect the CZ in complex and disrupting ways. The Arctic, in particular, is changing at a high pace, with temperature increasing much faster than the global mean. Permafrost is thawing, the Active Layer is deepening and wildfires affect vast high-latitude areas. The Arctic CZ is heavily impacted by all these processes, and it is exposed to new pressures that can lead to potentially irreversible modifications. We believe it is of utmost importance to monitor, measure and model the Arctic Critical Zone in all its components (soil, water, microbiota, vegetation, fauna, including geo/biodiversity) in a range of different environments, quantifying what is happening and estimating what could happen in the future and what prevention and adaptation measures could be implemented. Here, we propose that IASC TWG provides harmonization of existing Arctic Critical Zone observatories, allowing them to communicate, share protocols, knowledge and results, and define common scientific questions and modeling activities.