Permafrost covers 20-25% of the land surface in the Northern Hemisphere. Recent air temperature increase in the Arctic and Subarctic is significantly higher than the global average. Climate simulations predict continuing warming and increased wildfires occurrence. This rapid change is already leading to permafrost degradation, inducing ground subsidence and thermokarst, affecting land usability and stability of infrastructure. An increase in active layer thickness alters soil hydrology and groundwater drainage patterns.
Besides, large amounts of carbon and other inorganic elements, previously trapped in permafrost, are released towards aquatic systems. Microorganisms convert newly available highly biodegradable organic carbon into greenhouse gasses, amplifying global warming. As permafrost is known to contain vast amounts of frozen carbon, twice its current content in the atmosphere, its thawing poses a major risk because of the positive feedback on climate. Ultimately, climate change, through permafrost and habitat disturbance, affects local communities built on permafrost and threatens the traditional indigenous lifestyle. A better understanding of the impacts of permafrost thaw on soils, surface/groundwater fluxes (critical zone) and carbon cycle, as well as their controlling factors, will contribute to the understanding of permafrost-climate feedback.
Contributing to fill this knowledge gap, the overarching goal of the PRISMARCTYC project is to understand the different hydrogeomorphological and biogeochemical processes modifying permafrost soils, surface and groundwater runoff, driven by permafrost degradation in small watersheds.
This goal will be achieved by comparing different sites in Siberia, Canada and Alaska with different permafrost settings (e.g., ice-rich Yedoma permafrost or carbon-rich permafrost peatland; continuous or discontinuous permafrost), climate-sensitivity, vegetation, permafrost degradation types along a latitudinal and longitudinal gradient. The key study sites in Siberia and Canada have been chosen based on the expertise of the team members to cover a broad range of permafrost settings and degradation types, to allow cross-comparison. Central Yakutian lowlands (Eastern Siberia), Southwestern Yukon (Canada) and Chersky (North-Eastern Yakutia, Eastern Siberia) will be the main study areas where intensive fieldwork will be conducted. Olekma (Southern Yakutia, Eastern Siberia) and Batagay (Northern Yakutia, Eastern Siberia) will be the secondary study sites, where field research will be less detailed. Igarka (Western Siberia) and Alaska (transect from Denali Range to North Slope Toolik station) are selected as comparative sites as they were already studied by members of the project.
Work Package of the Project
A set of quantitative indicators (or ‘sentinels’) of the vulnerability of soils, surface- and groundwater is used to understand and cross-compare the impacts of permafrost degradation between the different sites. These indicators cover permafrost conditions, water chemistry, carbon cycle and microbial communities as major components of the permafrost-hydrosystem continuum. We analyze the differences and similarities between sites in terms of permafrost degradation, and develop and test numerous vulnerability/sustainability indexes for small watersheds encompassing different indicators.
The project is organized in several work packages (WPs) interacting with each other. Each WP focuses on a compartment and/or pathway of the near-surface permafrost-hydrosystem continuum:
Permafrost characteristics and degradation resulting from natural and anthropogenic disturbances
Impact of permafrost thaw on groundwater and surface water composition
Characterization of microbial processes and greenhouse gas emissions from ecosystems
Transversal WP: Indigenous community-based monitoring observatories
Management, synthesis and comparisons
Communication and education toward Arctic communities
Expected outcomes of the PRISMARCTYC project and scientific impact
By linking the different Work Packages together, from field and remote sensing studies of permafrost to the hydrosystems, the project is likely to produce several outcomes:
- Identification of changes in the critical zone and water resources in small Arctic watersheds from the modifications on soils, carbon cycle and ground/surface waters due to permafrost degradation subsequent to natural and anthropogenic disturbances. Those knowledge gaps were identified as priority in the last Intergovernmental Panel on Climate Change (IPCC) Special Report on the Ocean and Cryosphere in a Changing Climate (processes associated with release of carbon (greenhouse gases and dissolved carbon) and impact of widespread wildfires on permafrost-supported ecosystems)
- Co-construction of two indigenous (Evenk and Sakha) community-based environmental observatories stemming from indigenous and scientific knowledge on permafrost evolution resulting in a new monitoring protocol
- Improved communication toward local communities with support from citizen-based associations of the current and future modifications of soil and water resources due to permafrost degradation
- Production of a handbook for teachers in several languages to support education of climate changes and permafrost at school as developing outreach scientific activities toward children
- Gathering of a strong international multidisciplinary consortium able to fully understand a complex system under natural and anthropogenic disturbances