Permafrost

Definition

Permafrost is a layer of soil or rock that remains frozen for at least two consecutive years. It is commonly found in polar regions and high mountain environments.

5 Must Know Facts For Your Next Test

1. Permafrost covers approximately 24% of the Northern Hemisphere's land area.
2. Thawing permafrost can release significant amounts of greenhouse gases, such as carbon dioxide and methane, contributing to climate change.
3. The active layer above the permafrost thaws seasonally, allowing plant growth during warmer months.
4. Permafrost degradation can lead to ground instability, affecting infrastructure such as roads and buildings.
5. The presence of permafrost influences the types of vegetation and animal species that can inhabit an area.

Review Questions

• What percentage of the Northern Hemisphere's land area is covered by permafrost?
• How does thawing permafrost contribute to climate change?
• What are some potential consequences of permafrost degradation on human infrastructure?

Related terms

Tundra:

A biome characterized by cold temperatures, low biodiversity, and a landscape dominated by shrubs, grasses, mosses, and lichens.

Active Layer: The topmost layer of soil above permafrost that thaws during the summer and refreezes in the winter.

Methane Hydrates: Ice-like structures containing methane gas found in sediments beneath oceans and within permafrost regions.