When the topic of extinction events is brought up, there are immediate exemplars: the Chicxulub meteor that wiped the dinosaurs off the Earth, the vast Dutch consumption of the dodo, and the extermination of mammoths due to the life-altering effects of climate change – to name a few. Yet other species-killing events cannot hold a candle to “The Great Dying”, the most disastrous extinction event in history.
An Extinction Event
Mass extinction is a biological catastrophe in which a widespread and rapid decrease in Earth’s biodiversity in which the loss of life is significantly greater than the rate of speciation.
It is thought that 99.999% of all life that has ever existed is now extinct. National Geographic’s Michael Greshko comments that: “At least a handful of times in the last 500 million years, 75 to more than 90 per cent of all species on Earth have disappeared in a geological blink of an eye in catastrophes we call mass extinctions.”
Life Pre-”Great Dying”
ScienceNewsForStudents.org explained: “This Permian world teemed with life. On land, insects buzzed and crawled, including primitive dragonflies and cockroaches. Big, plant-eating reptiles and amphibians grazed its forests. The oceans were ruled by fish. Coral reefs thrived. Trilobites scuttled along the seafloor.”
Science Alert adds: “Our planet was a very different place during the geological period referred to as the Permian. Before the Great Dying, a vast expanse of ocean dominated the surface, surrounding a single continent named Pangaea.”
Geochronologist Seth Burgess stated: “It looked like business as usual until all of a sudden, everything changed.”
Devastation Of “The Great Dying”
It is extremely hard to picture the world 252 million years ago yet it was around this time that the Permian-Triassic Extinction Event transpired, aka “The Great Dying”.
In this, 90% of the species on planet Earth were wiped out, thus making it the deadliest mass extinction event of all time. Yes, 9/10 plants and animals were simply killed off.
This includes 96% of marine life (having had 76% of the ocean’s oxygen lost) and 70% of land life. Almost all trees withered and died. Perhaps no victim was bigger than trilobites, which were killed off entirely; they previously had lived for nearly 300 million years with 20,000 species.
It was a slow killing, taking over 60,000 years – slowly exterminating almost all life forms in existence.
Destroyed organisms such as forests took 10 million years to regrow. A lead researcher, Dr Hana Jurikova, said “It took several hundreds of thousands to millions of years for the ecosystem to recover from the catastrophe, which profoundly altered the course of evolution of life on Earth.” Live Science added: “it took 14 million years for the ocean reefs to rebuild to their former glory.”
Such an event instigated the start of the Triassic Period, part of the Mesozoic Era.
Taking place so long ago and millennia before the evolution of humans in the form of today, a whole load is still unknown. That said, we know it was the closest to the wipe out of all life on Earth that has ever come – thus nearly robbing all human lives and the lives of any flora and fauna today.
Theories For Causation
Many theories have been thrown up as to the cause of this crisis, all of which are not mutually exclusive.
Perhaps the most famous is the Siberian Traps volcanic eruption around the same time, which expelled 720,000 cubic metres of lava whilst releasing 14.5 trillion tonnes of carbon. Perhaps continuously erupting for as long as a baffling two million years.
The global environment was completely thrown for a loop with sea temperatures rising by a few or several degrees which may sound fine but are deadly for marine life and those affected by it.
CBS News adds that: “Researchers discovered a rare molecule called coronene in Italy and China which can only be formed when underground deposits of fossil fuels are super-heated.”
Geologist from Brock University in Canada Professor Uwe Brand drew the conclusion: “Over the course of a million years, extensive volcanic activity in what is now Siberia flowed through cracks and crevices of sedimentary rocks, searing oil and gas deposits as it moved along, producing the coronene scientists recently discovered…Carbon dioxide (CO2) concentrations during that time period are estimated to be a few thousand parts per million.” This number is particularly high. Even today’s levels, the highest in millions of years are still only 415ppm.
EarthSky reports: “The idea is that volcanic eruptions ignited vast deposits of coal, releasing mercury vapour high into the atmosphere.” Scientists said mercury created “an elemental signature of a catastrophe.”
The University of Washington’s Curtis Deutsch commented: “We are about a 10th of the way to the Permian. Once you get to 3-4C of warming, that’s a significant fraction and life in the ocean is in big trouble, to put it bluntly. There are big implications for humans’ domination of the Earth and its ecosystems.” In his own words, “It’s a very strong argument that rising temperatures and oxygen depletion were to blame.”
It seems a multitude of these factors led to the near eradication of all life on Earth.
Whilst “The Great Dying” nearly killed all life on Earth, it could be argued to provide conditions in which humankind had a better chance of thriving even if ages away from human evolution. Such argument is also used for the dinosaur extinction event 187 million years after the aforementioned extinction event.
It is likely we can never have the full picture of events as much as scientists work on it. What should be clear is the wipeout of the Earth’s population that nearly ended all civilisation is unparalleled but not unique. Another huge extinction event is to occur soon as it has in the past, it is only a matter of when.
Worryingly going forward, Curtis Deutsch at the University of Washington, proclaimed: “The very same things that caused the Great Dying are happening right now in our ocean today as a result of human activities,” he says, “not to the same degree, but in the same direction.”