Definition - What does Permafrost mean?
Permafrost is the name given to a layer of soil or bedrock in the Earth's surface, which is permanently frozen or has been for at least two years. It can reach depths of up to 5000 feet and is usually found in polar regions or areas with high latitude, or possibly very high altitude. It sits underneath approximately 5% of the earth's surface.
Safeopedia explains Permafrost
Permafrost has a significant effect on an ecosystem. When temperature changes in the air, thus in the soil beneath as well, this can result in the melting of permafrost, which has a significant impact on an ecosystem. An example can be seen where ice content in soil is high, the melting of permafrost can cause extreme erosion and loss of land, especially in coastal areas. This can also cause landslides.