Impacts of Arctic Environmental Change on Human Infrastructure and Ecosystems: Abrupt Permafrost Thaw Synthesis & Projections

In partnership with the Permafrost Carbon Network, this workshop will increase collaboration across research disciplines and geographies that have not previously had other venues to connect on this issue. Participants will evaluate current gaps in our capacity to anticipate the impacts of permafrost change on human infrastructure and ecosystems.

Four key goals of the workshop are to lay the foundation to:
• Assemble a cross-cutting working group of experts on the topic of abrupt permafrost thaw across a range of disciplinary expertise.
• Produce a quantitative synthesis of abrupt permafrost thaw rates and distribution
• Produce regional and circumpolar projections of abrupt permafrost thaw disturbance, overlaying these with current and future human infrastructure and ecosystem distribution.
• Communicate these products both as peer-reviewed publications and in formats designed to reach a range of user-communities

Permafrost (perennially-frozen) ground is widespread in the Arctic and provides the structural underpinning for human infrastructure and ecosystems in the region. Permafrost is defined by temperature, but ice and organic matter are other key components of frozen ground that shape the response of permafrost to rapidly changing Arctic conditions, and the cascading impacts on people. Gradual top-down permafrost thaw in response to environmental changes is the primary mechanism encoded into model predictions of changing permafrost landscapes and occurs on the (vertical) scale of centimeters per year.

Abrupt permafrost thaw describes the interaction between changing environmental conditions (weather, disturbance/fire), the melting of ground ice along with ground subsidence, and related changes in erosion and mobilization of soil. This process does not occur everywhere. It depends on the ground ice content that can be less than 20% and up to 80% of permafrost ground by volume, and the geomorphological aspects of the landscape undergoing change. But, as the name implies, where it does occur it is rapid and can be catastrophic, thawing through meters of frozen ground in a single season, disrupting ecosystems and human infrastructure at the surface.

As a result of the complexities of interacting factors, abrupt permafrost thaw has been studied extensively at the site scale, but it has defied incorporation into large-scale models that would allow for regional projections of landscape response.

The workshop will bring together experts across a range of disciplines to synthesize peer-reviewed literature on this topic with the goal of regional and circumpolar projections of the impact of abrupt permafrost thaw. Our community has recognized the important of abrupt permafrost thaw at the landscape scale and the past decade has produced a wealth of scientific measurements. While process modeling has also improved in this respect, credible ensemble model projections are still several years to a decade in the future.

To fill this gap, we propose a quantitative scientific synthesis of abrupt permafrost thaw in response to changes in weather and disturbance/fire. This primary goal will allow regional- and global-scale projections to include landscape distribution (maps) of abrupt thaw vulnerability. This workshop will lay the groundwork for immediate products and follow-on research projects that could arise, by assembling participants with cross-cutting expertise, as well as engagement with a broader circle of interested contributors even if they cannot attend.

Advance planning in combination with discussions at the workshop will be used to scope out the initial products that are possible as near-term workshop outputs. We will also to define mid-term outputs that could include additional peer-reviewed publications and future directions that could potentially shape research proposals outside the scope of the workshop. Finally, the workshop will aim to define user-audiences and communication platforms for broader audiences for this information. A workshop goal will be to enable at least one broader communication item.