What is permafrost?
Permafrost is a mix of soil, rocks, and sediment that absorbs water which then turns to ice and freezes. The ice combines the materials and creates solid areas of frozen ground. These areas are officially considered permafrost if they remain frozen for at least two years. Above the frozen ground is an ‘active’ layer that thaws during warmer summer months. The active layer varies in thickness, from approximately four inches to several metres. The frozen ground below it is referred to as the ‘ice wedge’.
The largest areas of permafrost are in Siberia, northern Canada, Alaska, and Greenland where temperatures do not often rise above freezing.
As the climate changes and temperatures rise, permafrost is thawing.
Why is permafrost important?
It is helpful to understand a little about soil and its composition to better grasp this carbon-storing process.
Soil is comprised of water, gases, and organic matter. The organic matter in soil contains carbon from carbon-based organisms (plants and animals) that have decomposed into it over time. You can read more about soil in our recent article, ‘Lets get grounded – why soils are underrated and disappearing!’
The absorption of carbon into soil and into the active layer of permafrost is part of the Earth’s natural carbon cycle. This cycle keeps the amount of carbon in the ground and atmosphere in a healthy balance.
Permafrost, found below the active layer of soil, also contains water (ice), gases, and organic matter. However, one key difference from non-frozen soil is that organisms do not fully decompose into it. Due to low temperatures, plant and animal remains can be preserved within the permafrost, sometimes for thousands of years. It is estimated that the oldest area of permafrost is 700,000 years old.
Besides carbon storage, another benefit of permafrost is that it connects areas of wetland and provides habitats for wildlife. Animals found in the arctic tundra include the musk ox, the Arctic hare, the polar bear, the Arctic fox, the caribou, and the snowy owl.
Why is thawing permafrost problematic?
The key issue is that as permafrost thaws carbon dioxide, methane and other greenhouse gases, are released into the atmosphere.
The release of CO₂ back into the atmosphere is a normal part of the natural carbon cycle. However, as is widely known, temperatures have increased from human activity. This has created a deeper thawing of permafrost and, therefore, faster release of CO₂. Rather than a natural cycle, this creates a vicious feedback loop. Too much CO₂ in the atmosphere causes temperature rises which in turn causes permafrost to thaw faster.
There is no scientific consensus on how much CO₂ will be released from permafrost in the next few years. However, it poses a serious risk to exceeding planetary boundaries given the state of already threatened environmental systems.
In addition to the risk of dangerous CO₂ release, there is a concern that as permafrost thaws viruses could be released. This is due to the partly decomposed plants and animals that are preserved in the ice from thousands of years ago. Due to their preservation, viruses contained within these organisms could be released and pose risks to humans, plants, and animals. According to the World Wide Fund for Nature (WWF) “four ancient viruses have been uncovered in previously frozen soil since 2004”.
Additionally, thawing permafrost means a loss of habitat for animals. As these habitats disappear animals will be forced to migrate.
It is also problematic for people living on or around areas of permafrost. This is because, as the ground thaws, it can create large sinkholes and cause roads to buckle. When it causes homes to shift it means that people have no choice but to relocate. One example where this is a serious problem is in Siberia where climate refugees are having to find new places to live.
What is being done to monitor this?
Addressing the risk and potential impacts of permafrost thaw requires extensive monitoring.
Nasa is taking an integrated approach to monitoring permafrost. This includes a combination of satellite observation and ground measurements.
The Woodwell Climate Research Centre are collecting data on permafrost emissions and working on strategies to protect Arctic communities. They have also partnered with the Arctic Initiative at Harvard Kennedy School, the Alaska Institute for Justice, and the Alaska Native Science Commission. The purpose of these partnerships is to ‘connect experts in climate science, human rights, and public policy with frontline communities and high-level decision makers’. The partnership is pioneering a six-year research program called Permafrost Pathways that will develop action plans to address the compounding impacts of permafrost thaw’. What can be done about permafrost thaw? – Woodwell Climate