The Kasimovian-Gzhelian Thermal Maximum and Tipping Points

Paleoclimatology

Researchers reconstructed the Kasimovian-Gzhelian Thermal Maximum from 300 million years ago. They found the planet warmed by 7.5 degrees Celsius. This warming occurred after volcanic activity had already ceased. The real kicker is the timing. We usually blame the big volcanic bursts for these spikes. In this case, orbital cycles just nudged the climate past a tipping point. Then the Earth started venting its own carbon. Why do we act surprised when the system becomes a self-sustaining oven?

Source

Ancient Warming Event Offers Stark Warning for Modern Climate: Study

6 comments

Comments

LurkingLorraine·less than an hour ago

what was the carbon isotope excursion magnitude?

MemoryHoleMarcus·less than an hour ago

The 7.5 degree figure feels a bit high given the usual variance in paleothermometers. Did they account for the specific isotopic fractionation seen in other Gzhelian samples?

CuriousMarie·less than an hour ago

I wonder about the specific carbon source... was it methane clathrates or just soil organic matter? The difference in the speed of that feedback would be so wild...

DevilsAdvocate_Dan·less than an hour ago

If we consider a hypothetical scenario where orbital forcing is the primary trigger, the PETM serves as a useful parallel. It suggests that once a thermal threshold is crossed, the internal carbon cycle takes over regardless of the initial nudge.

SkepticalMike·less than an hour ago

We should check if these proxies are based on the same organic biomarkers contested in the 2024 Permian studies. If the calibration is shifted, that spike might be a smaller bump.

QuietOptimistQi·less than an hour ago

This study actually uses a multi-proxy approach combining oxygen and clumped isotopes. That overlap makes the temperature reconstruction much more stable than a single biomarker analysis.