With more than 7.5 billion people we live on the blue ball called earth. There was a time not ‘to’ long where our blue ball warmed more than any human has seen, so far. This warming period took place over a period of just 200.000 years, which is a blink of an eye in the history of the earth.
It ended as quickly as it began suddenly and mysteriously. It all started out 56 Million Years Ago (MYA) at the end of the Paleocene epoch. The Paleocene epoch started 65 MYA, this was the time where the first large mammals and primitive primates lived. In the Paleocene epoch period, the world was still recovering from the Cretaceous-Paleogene extinction event (the big comet that wiped out the dinosaurs). In this time period, the world already was warm by today’s standards, there were no polar icecaps so the sea levels where much higher. The continents which were just beginning to take a familiar shape were covered in habitats like, tempered forests, deserts, and rainforests around the equator. So although it was already warm this was about to change in fewer than 20 thousand years the global average temperature changed from 3 to 8 degrees Celsius (today average global temperature 0.63 degrees Celsius). The warming was greatest at higher latitude. So at the poles, the land temperature was average 23 degrees Celsius and the ocean water was at a temperature of 20 degrees Celsius. so this means you could go for a comfortable swim around Antarctica. this period of fast-rising global temperature is known as the Paleocene-Eocene Thermal Maximum, also known as PETM. This time period had a massive effect on life on earth, Rainforests had expanded much further than they had anytime before.
How was this possible a sudden extreme rise in temperature? In ancient sediments from Maryland to Antarctica show that about 56 MYA there was a spike in the amount of carbon dioxide and other greenhouse gases in the oceans. These gasses likely came from organic matter, like plants. sediments that date back to the start of the PETM. show a large and sudden drop in the ration of carbon-13, compared to carbon-12. This means that a lot of biogenic carbon must have been released into the atmosphere in the form of carbon dioxide, methane, and other gasses. The carbon that was released during this time was only a fraction of the rate which it’s being emitted today! At the peak of the PETM, the amount of carbon that was released was estimated to be 1.7 billion metric tons per year for at least 4000 years. In 2014 alone, it was 9.8 billion metric tones of carbon. (I couldn’t find any clear info about 2017)
Remember I said that, during the PETM the globe warmed more than humans had ever seen, so far? well, keep in mind that, in recent years, the rate of annual carbon emissions have been more than five times greater than they were at the peak of the PETM. as a result, our world is warming faster than it did back then. just over the past 100 years, the average global temperature has increased by about 0.7 degrees Celsius. this may not seem much but at the peak of the PETM, it may have taken about 500 to 600 years for the temperature to rise that much.