New research from Harvard suggests the Sturtian glaciation, which lasted 56 million years, was not a continuous freeze. Instead, the planet likely underwent repeated cycles of thawing and refreezing driven by the interaction between volcanic CO2 emissions and basalt weathering. This feedback loop explains how the Earth could maintain extreme cold for millions of years while allowing oxygen-using microbes to survive during warmer intervals. The study highlights the critical role of the carbon cycle in regulating global temperatures over geological timescales.
