27 March 2025 | 13:30 - 15:00 (MDT)
Open Session - HYBRID
Room: Glen Miller Ballroom in UMC - 210 / 2012
Chair: Henry Burgess (IASC President, NERC Arctic Office, UK)
Session Description:
IASC Medal Recipient 2025 - Prof. Vladimir Romanovsky (University of Alaska Fairbanks, USA)
IASC Medal Lecture 2025: State and Fate of Permafrost in the Warming Arctic
Permafrost is a product of cold climates found on Earth in high latitudes and high elevations. Recent climate warming changed the permafrost “status quo” triggering changes in permafrost temperatures and in permafrost stability. The timing and rate of permafrost degradation are two of the major factors in determining anticipated negative impacts of climate warming on Arctic ecosystems and infrastructure. Degradation of permafrost is manifested in two distinct processes: increase in permafrost temperatures and thawing of permafrost. In this talk I will present several pieces of evidence of both of these processes observed now in most of the permafrost regions of the Earth with emphasis on Alaska. The results of more than 40 years of permafrost and active layer temperature observations in the North American and Russian Arctic and Sub-Arctic show substantial warming of permafrost. The magnitude of warming varied with location, but was typically from 0.4 to 4°C. However, this warming was not linear in time and not spatially uniform. The rate of the permafrost temperature increase is generally larger in the north and smaller in the southern part of the permafrost region. This climate and ground temperature warming has triggered the thawing of near-surface permafrost. Two types of permafrost thawing can be distinguished: an increase in the depth of the summer thaw layer (active layer) and the formation of a talik, a layer of soil or other earth material that does not freeze at any time during the year and may stay unfrozen for years, decades, and centuries. Increase in the active layer thickness is well documented in most of the permafrost regions based on direct measurements and on the results of remote sensing observations of the ground surface subsidence in the regions with ice-rich permafrost. The widespread process of new talik formations was documented in the Alaskan Interior and within other regions of warm discontinuous permafrost in the Northern Hemisphere.
Thawing ice-rich permafrost already produces significant differential subsidence of the ground surface called thermokarst in the affected thaw areas. The rate of subsidence in the most unfavorable locations can exceed 5 cm per year. Such a large and uneven subsidence of the ground surface already impacts numerous civil and industrial infrastructure with a significant high cost to repair and keep infrastructure functioning. Even more dangerous processes of thermal erosion may and very often are being triggered by thermokarst. This erosion can develop very quickly and put the affected infrastructure in immediate danger. Such development is already observed around buildings, roads, airports, and pipelines. The buried pipelines may be especially vulnerable to these processes. Thermokarst and thermal erosion may also cause lake drainage, imposing an additional hardship on the communities that use lake water as their drinking water supply. All these negative consequences of permafrost degradation will get more and more severe in the near future, which will require substantial and ever increasing spending to keep this civil and industrial infrastructure from failure.