PETMPaleocene Eocene Thermal Maximum
PETMPhysical Education and Tourism Management (academic department; Indiana University-Purdue University Indianapolis)
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It had been known that the PETM roughly coincided with the formation of massive flood basalts large stretches of ocean floor coated in lava, resulting from of a series of huge eruptions.
But it fits with the controversial proposal that a comet impact caused the PETM.
It is not yet clear what triggered the PETM event, although volcanic eruptions and methane gas releases from natural sources have been put forward as suggestions.
Future ecosystem disruptions are likely to exceed the relatively limited extinctions observed at the PETM," he said.
Unlike the relatively mild interglacials driven by the tilt, wobble and orbit of the Earth, the PETM fundamentally transformed the planet.
During the PETM, ecosystems had 20,000 years to adapt to carbon release, but at current rates of emission, "it is possible that this is faster than ecosystems can adapt," warns Kump.
Was the PETM a unique event in the early Paleogene greenhouse world, and what is the relevance of the PETM for current carbon injection from fossil fuel burning?
Interpreting ocean sediment cores, researchers proposed in 2013 that the PETM event released its carbon in just over a decade.
The results obtained indicate that the PETM was in fact preceded by a fall in sea level, the size of which is estimated to have been about 20 metres and the maximum descent of which probably occurred about 75 million years before the start of the PETM.
The PETM lasted about 160,000 years, and global temperatures rose an estimated 9 to 14 degrees Fahrenheit at its peak.
However, a gap in the floral record during the PETM has left open the possibility that a transient greenhouse effect introduced a dramatic but short-lived flux in plant life.