Melting Arctic:
Dark brown peat that has stored carbon for millenia erodes into the Chuckchi Sea.
Melting permafrost and worse fall storms has increased erosion all along this coast. One effect is that it is exposing peat, a form of fossil carbon, to the atmosphere. The peat oxidizes to release carbon dioxide and methane - both greenhouse gases. So global warming triggers the release of more greenhouse gases, triggering further climate warming. This positive feedback is one way that human-triggered climate change might get beyond our control.
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