The higher the temperature, the larger the extinction event, study finds

There is a distinct correlation between global temperature changes and the extent of mass extinctions, a study has found. 

Abrupt climate change, with environmental destruction from large volcanic eruptions and meteorites, has cause major mass extinctions over the past 539 million years.

Professor Emeritus Kunio Kaiho at Tohoku University decided to investigate the phenomenon, as there is little research looking at the divergent extinction rates between marine and terrestrial animals.

He found evidence that extinction rates in marine invertebrates and terrestrial tetrapods (mammals with four legs) responded to changes in global and habitat surface temperatures, regardless of warming or cooling.

The five major extinction events where huge losses of life occurred correlated with 7°C global cooling and 7-9°C global warming for marine animals and 7°C global cooling and 7°C global warming for terrestrial tetrapods.

‘These findings indicate that the bigger the shifts in climate, the larger the mass extinction,’ Kaiho said. ‘They also tell us that any prospective extinction related to human activity will not be of the same proportions when the extinction magnitude changes in conjunction with global surface temperature anomaly.’

Previous studies have showed that a 5.2°C rise in average global temperature would cause a mass extinction event, but Kaiho’s research shows an increase of 9°C would be needed to cause an event of this scale.

Based on current understanding, this would not occur until 2500 in a worst-case scenario.

‘Although predicting the extent of future extinctions is difficult because causes will differ from preceding ones, there is sufficient evidence to suggest that any forthcoming extinction will not reach past magnitudes if global surface temperature anomalies and other environmental anomalies correspondingly change,’ Kaiho said.

Terrestrial tetrapods were also discovered to be less resilient than marine animals to global warming events, while marine animals had a smaller tolerance to the same habitat temperature changes than terrestrial animals.

The research was published in the journal Biogeosciences. Kaiho now plans to predict the magnitude of possible future mass extinction events occuring between 2000-2050. 

Photo by Steffen B.