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Alaska Permafrost Thaw Releases Acid and Metals
Alaska’s thawing permafrost comprises releases of acid and metals that turn rivers orange for dozens of miles. The reported change comprises altered river water chemistry linked to permafrost thaw.
Permafrost:
| Dimension | Key Details |
|---|---|
| Definition | Permafrost comprises any ground that remains completely frozen at 32°F (0°C) or colder. |
| Minimum duration criterion | Permafrost consideration applies to ground that remains frozen for at least 2 years straight. |
| Oldest known permafrost | Scientists have discovered the oldest known permafrost in Siberia, which remains frozen for the past 650,000 years. |
| Common locations | Permafrost distribution comprises regions with high mountains and Earth’s higher latitudes near the North and South Poles. |
| Occurrence | Permafrost occurrence comprises locations on land and below the ocean floor. |
| Thickness range | Permafrost thickness comprises a range from 1 meter to more than 1,000 meters. |
| Spatial extent examples | Permafrost extent comprises entire regions such as the Arctic tundra, and single isolated spots such as a mountaintop of alpine permafrost. |
| Coverage in the Northern Hemisphere | Permafrost coverage comprises almost a quarter of the land area in the Northern Hemisphere having permafrost underneath. |
| Coverage percentages and Antarctica | Permafrost occurrence comprises 85% of Alaska and 55% of Russia and Canada, and comprises coverage of probably all of Antarctica. |
| Composition | Permafrost comprises a combination of soil, rocks, and sand held together by ice. |
| Near-surface carbon content | Near the surface, permafrost soils comprise large quantities of organic carbon from dead plants that cannot decompose due to cold. |
| Lower-layer composition | Lower permafrost layers comprise soils made mostly of minerals. |
| Active layer | The active layer comprises a layer of soil on top of permafrost that thaws during warm summer months and freezes again in the fall. |
| Active layer thickness in colder regions | In colder regions, the active layer comprises a very thin layer of only 4 to 6 inches (10 to 15 centimeters). |
| Permafrost loss | Permafrost loss, also known as permafrost thaw, comprises the progressive loss of ground ice in permafrost due to input of heat. |
| Impacts of permafrost thaw | Permafrost thaw comprises impacts: raised ocean water levels; a positive feedback loop with warming global temperatures; decomposition of organic matter emitting methane and carbon dioxide; formation of muddy slurry that cannot support soil and vegetation; damage to roads, buildings, and pipes; release of heavy metals such as mercury and other toxins that can pollute water sources; possible release of dormant, disease-causing microbes harmful to animals and humans. |