When will the sixth mass extinction occur on Earth
Article by: Andacs Robert Eugen, on 09 August 2022, at 11:04 am Los Angeles time
A climate researcher at Japan's Tohoku University has done the math, and he doesn't think the next mass extinction event will be like the five that preceded it.
On several occasions over the past 540 million years, Earth has lost most of its species in a relatively short geological period.
These events are known as mass extinctions and often closely follow climate change, whether it's extreme warming or extreme cooling, triggered by asteroids or volcanic activity.
When Kunio Kaiho tried to quantify the stability of Earth's average surface temperature and the planet's biodiversity, he discovered a largely linear effect. The greater the temperature change, the greater the extent of extinction.
In global cooling events, the largest mass extinctions occurred when temperatures fell by about 7°C. But for global warming events, Kaiho found that the largest mass extinctions occurred at about 9°C warmings.
That is much higher than previous estimates, which suggested that a temperature of 5.2°C would lead to a major mass extinction of the marine environment, just like the previous five great extinctions.
To put this into perspective, by the end of the century, global warming will cause surface temperatures to rise by up to 4.4°C. "Global warming of 9°C will not occur in the Anthropocene until at least the year 2500, in the worst-case scenario," says Kaiho.
The researcher does not deny that many extinctions on land and in the sea are already happening due to climate change, but he does not expect the same proportion of losses as before.
However, it is not just the degree of climate change that puts species at risk. The speed with which it is produced is of vital importance.
The largest mass extinction event on Earth resulted in the extinction of 95% of known species at the time and occurred over 60,000 years, approximately 250 million years ago.
Perhaps more species will disappear in the sixth Earth extinction event not because the magnitude of the warming is so great, but because the changes happened so quickly that many species could not adapt.
Regardless of how scientists interpret the data, it is clear that many species are doomed if we fail to stop climate change. The exact percentage of losses and when they will occur will be seen much later.