Carboniferous Era and Permian‑Triassic Extinction Reveal Past Climate Shifts

The Carboniferous period, occurring roughly 360‑300 million years ago, saw a massive removal of atmospheric carbon dioxide as plant material was buried and later transformed into fossil coal, representing the largest natural decarbonisation event in Earth’s history. Despite a drop in CO₂ from about 4 500 ppm to 500 ppm, temperatures did not fall as expected, suggesting that factors beyond carbon, such as solar activity, also drove climate change.

A new study of the Permian‑Triassic mass extinction, the most severe biodiversity loss about 252 million years ago, links the event to massive volcanic eruptions that released greenhouse gases, raising ocean temperatures and reducing dissolved oxygen. Researchers from Stanford University found that marine species lacking tolerance to warm, low‑oxygen water were the most vulnerable, a mechanism that mirrors contemporary concerns about oceanic oxygen loss under modern warming.

Both analyses underline how past carbon cycles and climate dynamics can inform current climate policy debates, highlighting that large‑scale CO₂ fluctuations have historically produced complex and sometimes counter‑intuitive climate responses.