Earth’s extinction history could be repeating


During the 4.54 billion years Earth has existed, five mass extinction events have occurred. According to scientists, a sixth mass extinction may possibly begin in fewer than 100 years.

Massachusetts Institute of Technology’s Daniel Rothman, after studying the carbon cycle and 31 extinction events from the previous 542 million yeas for some time, has noticed alarming parallels between the present and the Permian-Triassic extinction event that took place about 252 million years ago. This event is nicknamed “The Great Dying” due to a loss of 96 percent of the species on Earth. Per World Atlas, this catastrophic happening was triggered by a volcanic eruption that emitted so much carbon dioxide that it triggered extreme global warming and causing the acidity level of the oceans to rise.

The next mass extinction will be called the Holocene extinction if and when it occurs. This would be the first time carbon will once again be a factor in the extinction process.

The Ordovician-Silurian extinction occurred 439 million years ago and caused an 86 percent loss of life. The event was triggered by falling sea levels and the formation of glaciers. The extensive vegetation caused an extreme lack of carbon dioxide in the atmosphere, creating the glaciers. The Late Devonian extinction wiped out around 75 percent of the species on Earth about 364 million years ago. Plants on Earth during this time littered the oceans with nutrients, creating massive algal blooms and causing a lack of oxygen in the oceans. The next mass extinction has been mentioned previously; the Permian-Triassic extinction from 251 million years ago. The Triassic-Jurassic extinction from 214 million years ago was caused by asteroid impacts and global climate change. The Cretaceous-Paleogene extinction from 65 million years ago was caused by volcanic eruptions and asteroid impact – all according to World Atlas.

Scientists started wondering how soon it could happen again since these mass extinctions are relatively common in Earth’s history.

The critical level for carbon in the oceans is 310 gigatons and, according to Rothman, humans have the possibility of adding anywhere from 300 to 500 gigatons of carbon to the oceans by the beginning of the next century. By the time the year 2100 rolls around, the carbon cycle will have bypassed the critical threshold. Despite this, it could take up to 10,000 years for an actual extinction level event to happen. The number of years is determined by the time it takes for the carbon cycle to reset after it has been imbalanced. At current rates, this process usually takes around 10,000 years. According to Rothman and MIT, “the critical threshold is no longer tied to the rate at which carbon is added to the oceans but instead to the carbon’s total mass. Both scenarios would leave an excess of carbon circulating through the oceans and atmosphere, likely resulting in global warming and ocean acidification.”

As The Sun reporter Jasper Hamill states, humans have created 1,540 billion tons of carbon dioxide into the atmosphere since the Industrial Revolution.

“This is not saying disaster occurs the next day. It’s saying, if left unchecked, the carbon cycle would move into a realm which would be no longer stable and would behave in a way that would be difficult to predict. In the past this type of behavior is associated with mass extinction,” Rothman said to Hamill.

According to IFLScience, biodiversity on Earth is the highest it has ever been and the next event will bring about unknown consequences.