Geological studies reveal ancient climate feedback mechanisms and forest responses to carbon spikes

New geological research provides insights into how Earth's climate and ecosystems responded to massive carbon injections in the past. A study published in the Proceedings of the National Academy of Sciences suggests that for approximately 60 million years, a hidden climate thermostat operated via shallow seas. When sea levels rose, flooded continental shelves trapped phosphate, which reduced marine productivity and weakened the burial of organic carbon, allowing atmospheric CO2 to rise. Conversely, falling sea levels released this phosphate, boosting marine life and carbon burial.

Complementary research published in Science focuses on the Paleocene Eocene Thermal Maximum (PETM), roughly 56 million years ago. By reconstructing forest canopies using fossilized leaf cells, scientists found that rapid warming and volcanically driven carbon releases caused landscapes to become significantly browner due to reduced rainfall and shifting plant species. Researchers note that the current pace of human-driven CO2 injection into the atmosphere exceeds any known natural process, making these ancient records vital for understanding modern ecosystem responses to rapid warming.