A new major study has warned that if climate change continues on its current path one third of all plant and animal species will be extinct in the next 50 years. 

Researchers from the University of Arizona analysed data relating to weather trends and recent extinctions to give a grim prediction – revealed in journal Science Daily. 

The team surveyed data from 538 species and 581 sites across the world and found that 44% of species had gone extinct at one or more sites. 

This ‘local extinction’ indicates to scientists that changing weather can have a severe impact on species, and therefore means climate change is a threat to their long term survival. 

Evolutionary biologists Cristian Román-Palacios and John J. Wiens from the university led the study.

‘Detailed estimates’

“By analyzing the change in 19 climatic variables at each site, we could determine which variables drive local extinctions and how much change a population can tolerate without going extinct,” Román-Palacios said. 

“We also estimated how quickly populations can move to try and escape rising temperatures. When we put all of these pieces of information together for each species, we can come up with detailed estimates of global extinction rates for hundreds of plant and animal species.”

The study identified maximum annual temperatures as the vital piece of information which indicates if a population will go extinct. 

And the researchers found that average yearly temperatures showed smaller changes at sites with local extinction, even though average temperatures are widely used to report overall climate change.

‘Misleading’

“This means that using changes in mean annual temperatures to predict extinction from climate change might be positively misleading,” Wiens said.

Previous studies have focused on dispersal – or migration to cooler habitats – as a means for species to “escape” from warming climates. 

However, the authors of the current study found that most species will not be able to disperse quickly enough to avoid extinction, based on their past rates of movement. 

Instead, they found that many species were able to tolerate some increases in maximum temperatures, but only up to a point. 

They found that about 50% of the species had local extinctions if maximum temperatures increased by more than 0.5 degrees Celsius, and 95% if temperatures increase by more than 2.9 degrees Celsius.

‘Choose your own adventure’

Projections of species loss depend on how much climate will warm in the future.

“In a way, it’s a ‘choose your own adventure,'” Wiens said. “If we stick to the Paris Agreement to combat climate change, we may lose fewer than two out of every 10 plant and animal species on Earth by 2070. 

“But if humans cause larger temperature increases, we could lose more than a third or even half of all animal and plant species, based on our results.”

The paper’s projections of species loss are similar for plants and animals, but extinctions are projected to be two to four times more common in the tropics than in temperate regions.

“This is a big problem, because the majority of plant and animal species occur in the tropics,” Román-Palacios added.

• Read: Bumblebee populations down nearly 50 percent thanks to climate change

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Oli Gross

Oli’s career and personal ethical values both help shape his reporting of the diverse world of veganism. His background is in local newspaper and magazine journalism, and his work has included reporting court cases, celebrity interviews, business analysis, food and drink features and government legislation.

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