Source: USGS

The Dirt on Permafrost Melting

Key Vocabulary: permafrost, ecosystem erosion, sediment, Arctic, Antarctic, thaw, carbon sink, greenhouse gases, boreal forest, wetland, aquatic, extinction, infrastructure.

Next Generation Science Standards:

  • MS-ESS3-3. Ask questions to clarify evidence of the factors that have caused the rise in global temperatures over the past century.
  • MS-ESS3-5. Ask questions to clarify evidence of the factors that have caused the rise in global temperatures over the past century.
  • MS-LS2-1. Analyze and interpret data to provide evidence for the effects of resource availability on organisms and populations of organisms in an ecosystem.
  • MS-LS2-3. Develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem.

Article Guide: Permafrost_Article Guide

Human-caused climate change is a pervasive problem with devastating implications for the future of our planet, with global temperatures increasing at alarming rates. The rapid increases in temperature have been melting ice caps, rising sea levels, increasing soil erosion, changing weather patterns, and altering ecosystems. However, an important, yet little talked about that impact of climate change involves the melting of permafrost in and around Arctic and Antarctic regions.

What is permafrost?

Permafrost is permanently frozen ground of soil, sand, minerals, and rocks, found in cold climates where the layer does not thaw completely, such as Greenland, China, Russia, Canada, and Alaska. The ice binds the sediment, soil, and rock together, with the top few meters, called the active layer, thawing every summer and freezing every winter. The permafrost has to stay under 0°C for about two consecutive years and reaches depths of up to 1500 meters.

Permafrost also acts as a carbon sink, storing a large amount of buried carbon in the form of dead animals and plants. This is important because carbon sinks store more carbon than they emit. One way carbon sinks can be thought of as is a sponge absorbing carbon. When the plants die or leaves fall the carbon is added to the soil. The carbon can be buried and stored in the soil and in Arctic regions in the permafrost.

Why a melting permafrost is a problem:

The melting permafrost melting is part of a positive feedback loop, in which a change helps produce the conditions for more change to occur.  In this case, increased global temperatures have caused the permafrost to melt, allowing the organic matter trapped in the ground to be released. The greenhouse gases, such as carbon dioxide and methane, are being released from the organic matter into the atmosphere, which causes global temperatures to increase, continuing the cycle of permafrost melting.

 

The positive feedback loop of permafrost melting. Source: University of Edinburgh

And while the permafrost does go through periods of thawing and freezing from winter to spring, it is supposed to be a gradual process. A large amount of carbon dioxide should not be released from the permafrost layer and if the temperatures are continuing to increase then the permafrost may not go through the freezing part of the process. Researchers have predicted that the permafrost layer is expected to completely melt by 2090 by looking at climate models.

Carbon cycles through the atmosphere, the ocean, and the ground. Permafrost acts as a carbon sink. Source: NASA

Ecological Impact:

The melting of permafrost not only adds more greenhouse gases but also negatively impacts ecosystems. Most plants and wildlife have special adaptations that allow them to survive in the arctic, tundra, and boreal climates where permafrost is found. Plants in permafrost regions are adapted for lower soil moisture and the thawing of permafrost increases the soil moisture, hurt not only native plants but also wildlife. For instance, caribou and reindeer rely on these plants for a large portion of their diet. The loss of vegetation alters their diet and could leave them starving during crucial times.  

The increased thawing of permafrost can also alter habitats and change ecosystems, such as boreal forests becoming wetlands due to increased water availability. Species that are found in boreal forests will not be able to survive the habitat change and will bring new species that are more aquatic. The change in species composition can alter the biodiversity of these areas. This could change what future ecosystems look like, with some species likely going extinct.

Impacts on humans

The melting of permafrost is causing the ground to be unstable, which can be extremely costly for road maintenance, houses, buildings, etc. The unstable ground can cause breaks in roads, homes, and buildings to be destroyed, sinkholes, landslides, and mudslides. If the permafrost continues to melt and causes the ground to weaken, people who live in those areas may have to move elsewhere as those areas will become more dangerous to live in.

Alaska will feel the hardest effects of the permafrost melting. The future costs due to permafrost melting damage are estimated to raise public infrastructure costs about 10-20%, which would be around $4 billion to $6 billion by 2030 and then about $5.6 billion to $7.6 billion by 2080.

Photo Credit: landscapeonline

What can we do:

It is not too late for humans to take action and reduce greenhouse gas emissions. The mindset moving forward should not be that nothing can be done to stop climate change, but instead should be how can we make a difference. That begins by finding ways you can reduce greenhouse gas emissions, such as switching to energy-saving lightbulbs, adjusting the thermostat, turning off electricity when not in use, and so much more.

Photo Credit: Carolina Voigt

Renewable energies, such as solar and wind energy, should be used instead of burning fossil fuels. The switch to cleaner energy would be costly at first due to building wind turbines and solar plants, but the costs of wind and solar energy are projected to be as cheap or cheaper than coal by 2030. Reducing our greenhouse gas emissions must be prioritized to prevent the worst effects of climate change and permafrost melting.    

Learn more:

  • The New York Times has a short video of the scientists researching permafrost in the Yukon Delta National Wildlife Refuge in Alaska.

 

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