The Paleocene–Eocene Thermal Maximum (PETM) is a period of global warming that occurred ~56 million years ago, lasting approximately 200,000 years, when the Earth experienced global surface temperature elevations of ~5°C.
Hypotheses for the cause of this hyperthermal (short-lived warming) event have included destabilization of methane hydrates (ice-like solids of methane and water) due to orbital forcing (changes in incoming solar radiation due to variation in the tilt of the Earth’s axis and orbit) and uplift of the land causing weathering of marine rocks.
However, new research in Climate of the Past has suggested that volcanic activity within the North Atlantic contributed significant amounts of greenhouse gases to the atmosphere (it was active 63–54 million years ago but experienced peak volcanism 56–54 million years ago). Increased carbon emissions fall in line with a prominent spike in lighter carbon (12C) recorded in the shells of fossil microorganisms living in the oceans at the time, foraminifera. It enhances the greenhouse effect by trapping and absorbing heat radiating from the Earth’s surface, causing a positive feedback loop of ever-increasing temperatures.
This volcanism spans a vast North Atlantic Igneous Province (NAIP) located between Greenland, north of the United Kingdom and west of Norway, with the total volume of magma thought to have been emplaced up to 1,000,000 km3, equating to a carbon reservoir of 35,000 gigatons.
To determine the contribution of the NAIP on PETM climate change, Dr. Morgan Jones from the University of Oslo and colleagues, turned to the sediment record preserved on the island of Fur, Denmark, where a complete section preceding the PETM through to after the event is present, having been uplifted from the seafloor over millennia.
2023-08-21 18:48:03
Original from phys.org