But Arctic soil is rapidly melting — twice as fast as other parts of the world.
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Carbon dioxide, which contributes to global warming, is locked inside permafrost.
Siberia's Yamal peninsula saw a 160-foot-deep hole erupt in August.
In May, a Russian oil tank spilled, polluting Ambarnaya and Daldykan rivers and turning them red.
Ancient landscapes and animals — sometimes perfectly preserved — are revealed when the icy tundra melts.
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Maybe the freakiest element exposed by melting land? Diseases.
Read more stories about what's lurking beneath the ice.