Rapid increases in greenhouse gases have happened more frequently in the Earth’s history than previously realized, according to a Scripps Institution of Oceanography-led study published last week in the journal Nature.

Scientists have studied extensively the the Palaeocene-Eocene Thermal Maximum (PETM), about 56 million years ago, a period of rapid global warming that’s associated with a temperature spike on par with expectations for today’s global warming scenarios.

But according to the Scripps Institute, there’s been a series of six smaller greenhouse gas fluxes during the same geologic time period (the Palaeocene and Eocene epochs, 65 to 34 million years ago). These so-called “modest hyperthermals” (meaning a rapid, pronounced period of global warming) had shorter durations and recoveries (about a 40,000 year cycle) and involved an exchange of carbon between surface reservoirs into the atmosphere and then into sediment.

The researchers believe that large-scale carbon releases were vented from the ocean floor, but were reburied relatively quickly.

Tags: greenhouse gases, petm