Climate Change Causes Melting Permafrost in Alaska

According to new research from the University of Alaska Fairbanks Geophysical Institute, more areas of year-round unfrozen ground have begun to appear throughout the Interior and Northwest Alaska, and their extent, including the melting permafrost, will continue to grow as a result of climate change.

Talik Occurrence

The spread of taliks, according to the researchers, has major implications for carbon movement among minerals, organisms, and the atmosphere. Taliks are areas of permafrost that have unfrozen ground. It will also have an impact on the transfer of nutrients and the development of thermokarsts, which are areas of sunken land formed by permafrost thawing.

Their research, published in the journal Nature Geoscience, was written by Louise Farquharson, a research assistant professor. Co-authors include geophysics Emeritus Professor Vladimir Romanovsky, research assistant professor Alexander Kholodov, and research associate professor Dmitry Nicolsky. All four work at the Permafrost Laboratory of the Geophysical Institute. Romanovsky, Kholodov, and Nicolsky are also connected to Russian institutions.

Farquharson pointed out that the world is currently in a transition phase, in which talik formation is common, but it can refreeze if the year has little snow and very cold winter temperatures, or if the summer is cool. She also stated that by 2030, summer and winter air temperatures will have warmed to the point where talik formations will be inevitable, regardless of snow conditions.

Farquharson also stressed the importance of understanding the current state of permafrost degradation in Fairbanks, noting that it is not in a stable state. She predicted that as talik development progresses, the rate and extent of permafrost degradation will likely accelerate.

Permafrost Degradation

Taliks can form between the top of the permafrost and the bottom of the seasonally frozen layer, as well as within the permafrost due to water flow and within the permafrost due to previous thaw events, such as after a lake has been drained. They can also cut through the entire permafrost column in places where the permafrost is thin, such as near rivers or lakes.

The movement of material previously frozen in the ground can be one of the consequences of the new water. Dissolved organic carbon, dissolved nitrogen, and contaminants like mercury could all end up in streams and rivers.

Permafrost degradation will pose challenges for new construction as well as the maintenance of existing buildings and infrastructure.

For their study, the researchers looked at ground temperature data from dozens of Alaska sites in the Permafrost Laboratory monitoring network from 1999 to 2020. They then chose 54 of those sites to investigate, covering an area of about 116,000 square miles.

Accelerated Talik Formation

The scientists discovered that talik formation in the study area accelerated in 2017-2018 due to higher air temperatures and above-average snowfall. Heavy snow slows the transfer of heat from the ground to the atmosphere due to its insulating properties, extending the time it takes for the ground to refreeze and, in some cases, preventing a complete refreeze.

Talik formation at the study sites occurred only briefly in the 50 to 60 years before 2017-2018, according to the research team's modeling and observations.

The team also claims that current permafrost thaw assessments and projections underestimate the extent of the thaw because they ignore the impact of widespread talik formation, Science Daily reports.

The researchers projected that, under the high emissions scenario of the International Panel on Climate Change, talik formation by 2030 will have begun across up to 70% of the discontinuous permafrost zone, regardless of snow conditions. By 2090 talik thickness in areas of black spruce forest and warmer ecosystems may reach 40 feet.

The earth's climate trajectory, according to Farquharson, will likely make talik formation an important driver of permafrost degradation in the discontinuous permafrost zone and, eventually, in the continuous permafrost zone further north, as temperatures continue to warm. She went on to say that this will not only happen in Alaska but also in other Arctic regions and that talik formation will become a major permafrost degradation mechanism.