Scientists Say: Permafrost

This soil gets cold and stays cold

permafrost tunnel

This is a tunnel into permafrost outside of Fairbanks, Alaska. The walls on either side have been frozen solid for up to 25,000 years.

B. Brookshire/SSP


Permafrost (noun, “PUR-mah-frost”)

This is any soil that has been frozen for at least two years straight. In polar regions, air temperatures are below freezing for many months of the year, which allows the soil below to freeze. During summer, upper soil layers may thaw, allowing plants to grow. But underneath, a deep layer of soil remains permanently frozen.

In a sentence

Permafrost stores elements such as carbon — but if that soil thaws, it could release this contributor to climate change.

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Bethany Brookshire was a longtime staff writer at Science News Explores and is the author of the book Pests: How Humans Create Animal Villains. She has a Ph.D. in physiology and pharmacology and likes to write about neuroscience, biology, climate and more. She thinks Porgs are an invasive species.

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