The authors of a recent scientific study believe they’ve discovered the reason for the fastest known global warming in geologic history. The Paleocene-Eocene Thermal Maximum, a temperature spike 55 milion years ago, has now been connected to volcanic eruptions.

But volcanic eruptions alone could not explain the amount of CO₂ released. Scientists belief the emissions from the eruptions were only the starting point. Organic material in sediments cooked by lava could explain a chain reaction that ended up releasing up to an estimated 4,000 gigatons of carbon over the course of several millenia.

According to the authors of the study that release of carbon would have been the driving force behind the global global warming in that era. Other scientists however remain unconvinced that localised volcanic eruptions could set off global warming in this way.

Read more on this story from the San Francisco Chronicle