New Analysis Suggests Sixth Mass Extinction Could Occur By 2200

Ray Morris, via Flickr. CC BY-NC-ND 2.0

We’ve already been warned that our planet faces a sixth mass extinction, and some even believe that we are already in the early stages of such an event. Now, the harsh reality of the impending situation has been highlighted by the scientific journal Nature, with a special report detailing the threats that major animal groups face. According to the analysis, those predicted to take the greatest hit are amphibians, with an alarming 41% of species within this group facing extinction. But mammals and birds won’t get off lightly, with 26% and 13% of species similarly threatened, respectively.

Among the known critically endangered species are numerous different primates, such as the snub-nosed monkey, black rhinos, the yangtzee river dolphin, western gorillas and the Amur leopard. But many species that are currently only listed as endangered also face being wiped out, such as bonobos and loggerhead turtles.

The primary driver? Humans. According to the Living Planet Index, exploitation—such as hunting and fishing—is playing a major role in triggering the decline in animal species. Other human activities that are helping obliterate populations include agriculture and urbanization, whereby large areas of wild habitats are destroyed to make way for buildings, infrastructure, livestock and crops.

Climate change, which is primarily due to humans, is also threatening many sensitive animals, such as polar bears and corals, and will probably accelerate extinctions in ways that are currently unknown. Increasing CO2 emissions are not only warming our planet and seas, but they are acidifying our oceans, making them a more hostile environment for marine organisms. It’s estimated that 10% of all Earth’s coral reefs are already degraded beyond recovery, and if current pressures continue, 60% could be dead by 2050.

While we know that the situation is not good for many organisms on Earth, attempting to predict how quickly species are likely to disappear is extremely difficult, which only exacerbates the problem. Much of the uncertainty comes from the fact that we only know about a fraction of our planet’s biodiversity, and many unknown groups often reside in small areas that are already being demolished by humans and may never be assessed.

When scientists attempt to assess the number of species of animals, plants and fungi alive today, estimates are wildly varied, ranging from around two million to more than 50 million. Not only that, but approximations of the rate of extinction also vary, ranging from 0.01% to 0.7%, meaning the number of species disappearing is somewhere between 500 and 36,000 a year. If we use the upper rate, a mass extinction—or loss of 75% of species—could occur within the next few hundred years. At the lower rate, however, it may not arrive for thousands of years.

Five mass extinction events have occurred before, all of which were triggered by either natural planetary transformations or asteroid strikes. But the impending 6th event will be the work of humans, who have been gradually wiping out animals since mammoths and mastodons during prehistoric times.

So what can we do? According to the report, it’s of fundamental importance that countries start extending protected areas and devoting more resources to counting and evaluating stocks of life on Earth before they disappear.

[Via Nature, Nature, The Guardian and The Independent]

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