New Study Offers a Surprising Timeline For Earth's Sixth Mass Extinction

According to calculations done by a climate scientist at Tohoku University in Japan, the current mass extinction event is not expected to be as devastating as the previous five. Certainly not for several more centuries.

Earth has lost the majority of its species on several occasions during the past 540 million years in a very small geologic time period.

These are referred to as major extinction events, and they frequently occur just after a climatic shift occurs, whether it results from extremely high or extremely low temperatures brought on by asteroids or volcanic activity, respectively.

When Kunio Kaiho attempted to quantify the relationship between the stability of Earth's average surface temperature and its biodiversity, he discovered a mostly linear relationship. The amount of extinction increases with temperature change.

The largest mass extinctions during global cooling episodes happened when temperatures dropped by around 7°C. However, Kaiho discovered that throughout times of global warming, the largest mass extinctions happened at about 9°C of warming.

That is far higher than earlier predictions, which indicated that a temperature increase of 5.2°C would cause a significant marine mass extinction on par with the previous "big five."

To put it in perspective, contemporary global warming is projected to raise surface temperatures by as much as 4.4°C by the end of the century.

Under the worst case, Kaiho asserts that the Anthropocene won't see 9°C global warming until at least 2500.

As a result of climate change, many species are already becoming extinct on land and in the water, although Kaiho does not anticipate the same number of losses as in the past.

However, species are at risk for many reasons than just the severity of climate change. The pace at which it happens is crucial.

The biggest mass extinction on Earth, which happened around 250 million years ago and lasted over 60,000 years, resulted in the demise of 95% of all known species at the time. But because of human emissions of fossil fuels, today's warming is taking place over a considerably shorter period of time.

Instead of the amount of warming being so high, it's possible that more species may go extinct during Earth's sixth extinction event since many of them were unable to adapt.

Because the reasons of the anthropogenic extinction are different from the causes of mass extinctions in geologic time, Kaihu acknowledges that it is difficult to predict the future anthropogenic extinction magnitude using simply surface temperature.

No matter how scientists analyze the evidence, it's obvious that unless we can stop climate change, many species are doomed.

There is still disagreement over the precise percentage of losses and the timing of those losses.

The study was published in Biogeosciences.