The PETM – Why It Feels Like Deja VuThe Palaeocene Eocene Thermal Maximum was an event that took pla

The PETM – Why It Feels Like Deja VuThe Palaeocene Eocene Thermal Maximum was an event that took place 56 million years ago at the end of the Palaeocene and lasted for 150,000 – 200,000 years. The average global temperature rose by 5-9°C (9-16°F) leading to mass migrations and extinctions of flora and fauna.The event was discovered when marine sediment cores from Antarctica showed a large and sudden excursion ( a sharp spike in the values) in carbon isotopes, indicating that a large amount of CO2 had been rapidly expelled into the atmosphere. Sounds familiar doesn’t it?Further evidence of a large expulsion of CO2 is shown within marine sediment cores. As you can see, there is an abrupt change from white to red, indicating a rapid dissolution of calcium carbonate (white mud) that only recovers after the event (the red clay). (Increases in CO2 dissolved within seawater lead to calcium carbonate dissolving and eroded terrestrial clays (red) are deposited instead).Today global temperatures are increasing at rate that far exceeds that of the PETM; a warming of 1°C per 100 years compared to 0.025°C in the Palaeocene.While current global temperatures are far lower than those during the PETM it is the speed of the change that matters. All life forms take time to adapt and evolve, and it is the rapidity with which the world is warming that is threatening life as we know it. Humans are not immune to this change, and it is very likely that the current warming could lead to the next mass extinction if it is not curtailed.Climate change is still a topic of hot debate but the most important fact to remember is this: No matter what happens the Earth will still exist and life will find a way to go on. The Earth has survived global glacials as well as global deserts and has feedback cycles that always return it to a habitable state. However, these climate shifts always incur casualties, and if there is another mass extinction, there is no guarantee that the human race will survive to tell the tale. There is no doubt that humans are expelling large volumes of CO2 into the atmosphere and therefore control over the future really does lie in our hands.WatsonReference: https://www.e-education.psu.edu/earth103/node/639Further Reading: http://www.wunderground.com/climate/PETM.asp?MR=1http://www.skepticalscience.com/co2-rising-ten-times-faster-than-petm-extinction.htmlhttp://www.geol.umd.edu/~jmerck/geol100/lectures/36b.htmlImage Credit: University of California Santa Cruz - Earth and Planetary Sciences -- source link

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