A climatologist at Tohoku University in Japan has clocked the numbers and doesn’t think that today’s mass extinction event will equal that of the previous five. At least not for the next several centuries.
On more than one occasion over the past 540 million years, the Earth has lost most of its species in a relatively short geologic time period.
These are known as mass extinction events, and often follow closely in the aftermath Climate changewhether due to extreme warming or extreme cooling caused by asteroids or volcanic activity.
When Kunio Kaeo attempted to measure the stability of Earth’s average surface temperature and the planet’s biodiversity, he found a largely linear effect. The greater the temperature change, the greater the extent of extinction.
For 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 warming.
This is much higher than Previous Estimatesindicating that a temperature of 5.2 °C would lead to a major marine mass extinction, on a par with the previous ‘Big Five’.
To put that in perspective, by the end of the century, modern global warming will be On track to increase surface temperatures by up to 4.4°C.
Kaiho does not deny that many extinctions on land and at sea are already caused by climate change; He just does not expect the same percentage of losses as before.
However, it is not only the degree of climate change that puts the species at risk. The speed at which it occurs is very important.
The largest mass extinction event on Earth killed 95 percent of the known species at the time More than 60,000 years About 250 million years ago. But today’s warming is occurring on a much shorter time scale thanks to human emissions of fossil fuels.
Perhaps more species will die in Earth’s sixth extinction event not because the scale of warming is too great, but because the changes happened so quickly that many species couldn’t adapt.
“Predicting the magnitude of future anthropogenic extinctions using only surface temperature is difficult because the causes of anthropogenic extinctions are different from the causes of mass extinctions in geological time,” Caillou admit.
No matter how scientists split the data, it’s clear that many species are doomed to extinction unless we can stop climate change.
The exact percentage of losses and the timing of those losses remain under discussion.
The study was published in Biological Sciences.
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