We can't stop our planet's next mass extinction event, researchers say

Not only is Earth in the middle of its next mass extinction event, but it may be too late to undo the harm inflicted upon the planet’s species. This is according to a new study assessing evidence of what it calls an “ongoing extinction event.”

The study was published in Biological Reviews, and conducted by biologists from the University of Hawaii and the Museum National d’Histoire Naturelle in Paris. While researchers say that conservation initiatives have been put in place to combat the crisis and protect certain species, the study suggests that the damage has already been done.

“These initiatives cannot target all species, and they cannot reverse the overall trend of species extinction,” reads a press release that accompanied the study.

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Robert Cowie is the lead author of the study and a research professor at the University of Hawaii at Manoa’s Pacific Biosciences Research Center. He and the study’s co-authors estimate that since the year 1500, as many as 7.5 to 13 per cent of Earth’s two million known species have already gone extinct. That translates to between 150,000 and 260,000 species. These numbers were extrapolated from estimates obtained for land snails and slugs.

“Including invertebrates was key to confirming that we are indeed witnessing the onset of the Sixth Mass Extinction in Earth’s history,” said Cowie in the press release.

According to experts, there have been five mass biodiversity extinction events in Earth’s history, each wiping out between 70 and 95 per cent of plant, animal and microorganism species. The most recent one was 66 million years ago and resulted in the disappearance of dinosaurs. Each was caused by natural phenomena.

The idea that the world is confronting yet another mass extinction event isn’t new, with previous studies showing that the rate at which the world’s species are dying out has accelerated in recent decades. Research also suggests this latest crisis is caused entirely by human activities.

GREATER IMPACT ON ANIMALS THAN PLANTS

Based on the study, extinction appears to affect different populations of species in different ways depending on their habitat.

“Although marine species face significant threats, there is no evidence that the crisis is affecting the oceans to the same extent as the land,” said the press release.

Additionally, island species, such as those inhabiting the Hawaiian Islands, are more impacted by extinction events than continental species, and the rate of extinction for plant species appears to be lower than that of terrestrial animals.

The study analyzes many other investigations into plant extinctions across different regions of the world, noting that such research has generally produced low figures. About 0.55 per cent of the overall flora in Mediterranean Europe has gone extinct, for example, while 2 per cent of the native flora of Europe and Israel has been lost. Researchers also note that while examining studies comparing local extinction rates among taxonomic groups, it appears as though “plants usually have lower extinction rates than invertebrates.”

While this has yet to be demonstrated on a global level, researchers said it’s possible that plants may indeed have a lower rate of extinction than animals.

WHAT NEEDS TO BE DONE?

A mass extinction event generally involves the loss of at least 75 per cent of species. While the study noted that the current ongoing extinction crisis has not yet hit such a high rate of extinction, there is still potential for this to happen in the future, and scientists argue it’s in the process of happening right now.

Going forward, the study’s researchers state that conservation efforts should be maintained in order to prevent further damage to species, and that more research on existing species must be prioritized.

“The biodiversity that makes our world so fascinating, beautiful and functional is vanishing unnoticed at an unprecedented rate,” the study reads. “In the face of a mounting crisis, scientists must adopt the practices of preventive archaeology, and collect and document as many species as possible before they disappear.

“Denying the crisis, simply accepting it and doing nothing, or even embracing it for the ostensible benefit of humanity, are not appropriate options and pave the way for the Earth to continue on its sad trajectory towards a Sixth Mass Extinction.”