According to study conducted by researchers from University of Southampton, UK, extreme global warming event 56 million years ago was driven by massive carbon dioxide (CO2) emissions from volcanoes, during formation of North Atlantic Ocean.
They had used combination of new geochemical measurements and novel global climate modelling to show that Palaeocene-Eocene Thermal Maximum (PETM) was associated with rapid doubling of atmospheric CO2 in less than 25 thousand years because of CO2 emissions from volcanoes.
The PETM was most rapid and extreme natural global warming event of last 66 million years. It had lasted for around 150 thousand years and increased global temperatures by at least 5 degrees Celsius. Its period coincided with the formation of massive ‘flood basalts’ — large stretches of ocean floor coated in lava, resulting from of a series of huge eruptions.
Earlier it was suggested that PETM event was caused by injection of CO2 into ocean and atmosphere, but ultimate trigger source of CO2 was not known. Now researchers believe that, the CO2 was released during land drifts, separating Greenland from north-western Europe, thereby creating North Atlantic Ocean.
During this time, more than 10,000 petagrammes of CO2 was released predominantly from volcanic source. This is a vast amount of CO2, 30 times larger than all fossil fuels burned to date and equivalent to all current conventional and unconventional fossil fuel reserves.