Changing Permafrost
What is happening to permafrost?
Permafrost is an important component of the water cycle and Arctic ecosystems in general. It provides a watertight layer of soil at the surface of the tundra that allows for surface water to collect during the warmer months. These shallow lakes serve as habitats for fish and invertebrates and provide food and breeding grounds for other animals such as birds and mammals.
However, in recent years there have been drastic changes to our permafrost that have been concerning scientists. The Arctic is warming four times as fast as the rest of the planet because of climate change, and what was continuous permafrost is now thawing faster than ever. This is concerning because permafrost stores a large amount of carbon and methane, which are greenhouse houses. As the permafrost thaws, these gases are released into the atmosphere, adding to the global warming.
Furthermore, about 35 million people live in a permafrost zone, and they're feeling the direct effects in their everyday lives. Collapsing shorelines, failing infrastructure such as bridges, roads, and buildings, and changes in hunting grounds are some of the impacts these communities are witnessing.
It is also worth noting that the indigenous communities living in these permafrost zones are having to make changes in their lifestyle as what was once a stable environment is becoming less and less reliable. These populations are also less likely to have access to supportive aid when their communities are affected. According to the Canadian Climate Institute, "Damage to roads is also limiting access to food, essential supplies, and medical services."
Where are we seeing signs of accelerated permafrost thaw?
The map below shows some of the places seeing signs of accelerated permafrost thaw. Clicking on the right, top corner will open the map in it's own window in Padlet, which makes it easier to explore each place. You're also welcome to add your own observations!
What scientific evidence do we have that permafrost thaw is accelerating and that this is due to global warming?
Scientists have been studying permafrost thaw since the 1970s!
One of the ways they do this is by drilling boreholes into the ground to measure the temperatures of permafrost at different locations and underground depths, to see how it changes over the years. Data collected by the University of Alaska Fairbanks over the past 40+ years shows a pattern of increasing permafrost temperature at different locations across Alaska, a total of 15 boreholes. (Figure 1)
The Deadhorse borehole, located in the Arctic Coastal Plain by Prudhoe Bay oil field, is one of the locations showing the fastest increase in permafrost temperature. As you can see, it has one of the steepest curves, which indicates faster change than others.
Measurement depths inside the boreholes are between 49 and 85 feet. When the data is represented on a map of Alaska like the one in Figure 2 (right), we can see that the greater rate of thawing is happening further up North, as locations get closer to the North Pole and this is because the Arctic has been warming almost four times faster than the rest of globe as a whole.
Satellites are also used to detect and monitor changes in the permafrost. They do this by collecting data on the temperature of the ground and the amount of water in soil, which help determine the rate of thaw.
Other type of information that satellites collect to monitor changes in permafrost due to a warming climate are:
photographs of how Arctic landscapes are changing over time (Figure 3 shows ponds forming in northwest Siberia as a result of permafrost thaw),
tracking changes in vegetation on the tundra,
measuring levels of carbon dioxide and methane (which are released into the atmosphere by thawing permafrost).
Why should we care about thawing permafrost?
Thawing permafrost is having an impact on both the natural environmental and the built environment. Among the biggest concerns related to the thawing of permafrost, is the release of greenhouse gases into the atmosphere. The Arctic and its permafrost used to be considered overall a carbon sink. However, recent research from The Arctic Institute has shown that permafrost is now emitting more carbon than it is absorbing. This creates a positive feedback loop, leading to a warmer planet overall, not just for Alaskan communities.
Other issues related to permafrost thaw are:
Receding shorelines- from increased erosion as there is less frozen permafrost to hold the ground together along the coast.
Infrastructure damage- most of the infrastructure of Northern Alaska has been built on permafrost. What once was solid ground is now thawing and refreezing each year, meaning that the buildings, bridges, roads and pipelines that were built on permafrost ground are shifting and breaking.
Thaw slumps- the thawing ground along riverbanks and lake shores is resulting in big drops due to erosion. This makes these bodies of water more difficult to access and increases sedimentation in the water, which might affect fish population.
Changes in indigenous ways of life- For example cellars built deep in the permafrost by Native Alaskans hunters are thawing, preventing them from being able to safely store their meat for the year.
What can we do about it?
There are a few theories on how we can stop the thawing of permafrost. Some researchers in Siberia are combating the problem by introducing animals like bison, horses, and other herbivores to help recreate a grassland environment, which would help keep the underlying permafrost cool. However, the idea of "rewilding the Arctic" could be timely and costly. On a large scale, the most impactful way to stop permafrost thawing is to be aware of and reduce our carbon footprints. Large corporations produce huge amounts of carbon and other substances every year that increasingly warm the atmosphere. If we can find a way to reduce the amount of fossil fuels being reduced, we will be able to keep permafrost from thawing even more than it has.