Humans may be among ‘walking dead’ species

Not long left: Some of nature’s most impressive beasts are among those facing imminent wipeout.

Scientists in the USA and Mexico say mankind is now responsible for the sixth mass extinction event in Earth’s history. If we all die, will those who come next miss us?

It grows up to eight feet long, weighs 330lb and can run at 35mph: the South China tiger looks as if it could overcome almost anything. But this formidable cat has all but lost its battle for survival; it has now not been seen in the wild for more than 25 years.

According to a new study conducted by scientists at American and Mexican universities, the recent “biological annihilation” of wildlife is evidence that we are living through the Earth’s sixth mass extinction event, of which the critically endangered tiger is at risk of becoming just one more victim. The study found that billions of animal populations, from mammals and birds to reptiles and amphibians, have been lost and a more detailed analysis of 177 land mammal species found that almost half have seen a 80% decrease in population numbers since 1900.

In a previous report by the same authors, Paul Ehrlich describes “species all over the world that are essentially the walking dead.” For human beings, it is both a damning indictment and a loud warning. Problems largely caused by our species — climate change, deforestation and pollution — are the key causes of the phenomenon. And humans may be among the first to disappear if these processes are allowed to continue.

The study joins a series which suggest that Earth is now rapidly losing species. And although exact projections vary, in 2015 a professor at the University of Connecticut suggested that climate change alone could cause one in six of those currently alive to be extinct by the end of the century.

The most recent and famous of the previous five mass extinctions was the Cretaceous-Tertiary event which killed the dinosaurs 65 million years ago and is believed to have been caused by a huge asteroid landing in the Yucatan Peninsula in Mexico. Worryingly, the authors of this study suggest that “the window for effective action is very short, probably two or three decades at most.”

Mankind unmourned?

Some doubt whether the world would miss the human race. Over 99% of species who have ever lived on Earth are now extinct, and one day we will join them. We will be quickly forgotten or, perhaps more deservingly, be remembered as a destructive and selfish force undeserving of our place on this beautiful planet. Those who follow us will be glad to be rid of us.

Others say that, in millions of years of evolution, there is nothing more extraordinary than our species. With our abilities in communication, technology and travel, to name but a few, we have deservedly become the dominant force on the planet. Our absence would deprive the world of its greatest pioneers. And no other species cares as much about the fate of others as we do.

You Decide

  1. Would the world miss the human race?
  2. Is it inevitable that humanity will cause a sixth mass extinction?

Activities

  1. Create an advert asking for help in saving an endangered animal. Explain how and why it should be saved. Use the WWF’s list in Become An Expert to help you choose one.
  2. Choose three threats to humanity’s existence and prepare a three-minute presentation explaining each of them. Give each one a rating out of 10 to show how likely you think it is to wipe us out. Use Anders Sandberg’s article in Become An Expert to help.

Some People Say...

“We became the Earth’s infection a long and uncertain time ago.”

James Lovelock, environmentalist

What do you think?

Q & A

What do we know?
We know that a mass extinction event would be very difficult for mankind to survive because we rely on the food chain. Even seemingly insignificant changes could have a big impact. For example, as the study’s authors suggest, if bees stop pollinating everywhere except in one meadow, the plants they pollinate would cease to exist outside of that meadow. That could extinguish a vast array of plants which we, and many of the animals we farm, rely on.
What do we not know?
Whether we really are experiencing the Earth’s sixth mass extinction event. Extinction occurs naturally anyway, but the vastly increased rate of population depletion appears to be the result of problems created by humans. We also do not know if there’s anyway to stop it if it is currently happening.

Word Watch

Not been seen in the wild
By 1996 there were only between 30 and 80 South China tigers left; most of the others had been killed by hunters. Now some live in zoos, and there are plans to reintroduce them to the wild in South Africa.
According to a new study
The study is from Stanford and UNAM (Universidad Nacional Autónoma de México) and was published in Proceedings of PNAS (the USNational Academy of Sciences). Although there is widespread agreement that mankind is causing extinctions around the world, there is not a scientific consensus that we are definitely living through a “mass extinction” period. Some scientists say, for example, that figures based on extrapolations from known data cannot be assumed to be accurate.
Critically endangered
The World Wildlife Fund (WWF) has given 19 animals this status, which is their most severe.
Previous five mass extinctions
The most extreme of these was the Permian mass extinction, when 96% of all species died out.

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