The Sixth Mass Extinction

Artist's Impression of the Chicxulub Impact

Artist’s Impression of the Chicxulub Impact
Image courtesy of NASA

The most famous mass extinction is the Cretaceous-Tertiary, which killed the dinosaurs 65.5 million years ago. It was most likely caused by a meteorite that left a crater 150 miles in diameter off the Gulf of Mexico and a layer of iridium-rich dust all over the planet.

However the Permian-Triassic extinction was the most dramatic. Scientists still debate what cataclysm could have caused 90 percent of all life on Earth to suddenly vanish 250 million years ago. Meteors, mass volcanic eruptions, global warming, and even a sudden burst of space radiation have been proposed to explain it.

A solid consensus of biologists have established that the Earth is now experiencing a Sixth Mass Extinction event, the Holocene Extinction. This Mass Extinction event began 100,000 years ago, it’s like nothing the planet has ever seen before, and it’s all our doing.

It is theorized that Native Americans wiped out 80% of the North American animals within 1,000 years of their arrival, driving the giant ground sloths, camelids, giant armadillos to extinction. The disappearance of Woolly Mammoths, Irish Elk, Cave Lions, Cave Bears, Cave Hyenas, and even Neanderthals occurred after humans arrived in Europe. The ecosystems of Australia, the Caribbean, and Madagascar suffered collapses in biodiversity shortly after humans appeared in their environments 40,000, 8000, and 2000 years ago respectively.

Today the Earth is losing 30,000 species per year. That averages out to three species going extinct every hour, and with them go their genetic uniqueness, beauty, and contributions to our ecosystem. Each species lost detracts irretrievably from our own quality of life. Extinction is forever.

Physicist Adam Lipowski, through computer modeling, has found that, throughout evolutionary history, mutations regularly produce “superpredators,” a life form so stressing on the ecosystem that it extinguishes entire food chains, destroying even itself in the process.

Are humans a superpredator? Obviously we once were, through no fault of our own, but through the success of our genetics. We didn’t know any better; today, however, we have science, which is a blaring klaxon, alerting us to what we are doing to our planet’s biodiversity and ourselves. Human beings, unlike sharks and bacteria, have a cerebral cortex. This component of our brains gives us the ability to override our baser impulses and become masters our fate.

Artist's Impression of the Chicxulub Impact

American bison skull heap.
Image courtesy of Wikimedia.

The World Conservation Union currently lists 40 percent of all species on Earth as endangered. This is a terrifying statistic, but it also means that there is still hope. There were a scant 750 bison left in America in 1890. Today we have brought their numbers up to 350,000, far less than the 60-100 million estimated to have roamed the United States in the mid-1800s, but proof that we still have some time left to change our course.

The world’s frogs, bees, polar bears, whales, and fish stocks are our planet’s “canaries in the coal mine,” and what drives them to extinction may mean our own demise. Unlike miners who can escape to the outside, we have no other planet to run to. Over 99% of species that ever lived are now extinct. Let’s not join that statistic.

Additional Sources

Michael J. Benton, When Life Nearly Died: The Greatest Mass Extinction of All Time, Thames and Hudson, 2003.



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