The first Snowball Earth
Life poisoned the air and froze the planet for 230 million years
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The Huronian glaciation comprises at least three separate ice ages, preserved in the Huronian Supergroup north of Lake Huron and in equivalent deposits in South Africa and Australia. The mechanism is well understood: methane is a far more powerful greenhouse gas than CO₂, but oxidises rapidly in the presence of oxygen. When the Great Oxidation removed the methane, the greenhouse collapsed. The high albedo of ice amplified the cooling until it became global. It is the clearest case in Earth history of biology steering the climate — and of doing so to its own disadvantage.
For children
Before oxygen arrived, methane in the air kept Earth warm like a blanket. When oxygen rose it destroyed the methane — and the blanket was torn away. Earth froze over for more than two hundred million years. It is the longest ice age we know of, and life itself caused it.
Connects to
Part of Terra Saga — the story of Earth on a timeline. terrasaga.org