Ancient Warming Tied To High Concentrations Of Volcanic CO2

University of Southampton researchers led an international team of scientists in a study of one of the extreme warming events believed to have taken place 56 million years ago. According to their analysis, this ancient global warming may be strongly tied to volcanoes and their massive volcanic CO2 emissions.

Volcanic CO2 Led to the PETM?

The study team made use of a combination of novel global climate modeling and new geochemical measurements. They did do to try and better find a link between PETM and atmospheric CO2.

PETM is the Palaeocene-Eocene Thermal Maximum, which is considered as being the most extreme and rapid natural global warming even registered over the last 66 million years. It is believed to have lasted for about 150.000 years. During this period, the global temperatures are thought to have increased by more than 5 degrees Celsius or 9 Fahrenheit degrees.

The injection of carbon into the atmosphere and oceans was found to have been the underlying cause of this event. However, the source of the CO2 remained elusive, at least until now.

Previous studies suggested a possible link between PETM and the formation of flood basalts in the North Atlantic. These are massive swaths of the seafloor covered in lava.

In looking to find a clear association, the current study analyzed foraminifera or fossilized plankton. The changing isotopes in their shells helped offer a clear image at the altered pH levels of the oceans. In turn, this also helped point out the origin of the Co2 and also estimate and determine a quantity.

“Ocean pH tells us about the amount of carbon absorbed by ancient seawater, but we can get even more information by also considering changes in the isotopes of carbon, as these provide an indication of its source,” stated Andy Ridgwell, a study co-author.

This helped prove that volcanic CO2, or the opening up of “large-scale volcanism” in the North Atlantic” was the most probable driving force of PETM.

The research team published its results in a paper in the journal Nature.

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