Advertisement

Earth's sixth extinction 'already underway'

Scientists say the sixth "mass extinction" is already well underway on Earth, with the loss of wildlife in recent decades referred to as a "biological annihilation".

According to new research, the decimation of both common and endangered wildlife populations is more severe than previously feared.

Scientists have documented that billions of regional and local populations have been lost, blaming overpopulation and overconsumption for the crisis.

They have warned that loss of biodiversity threatens the survival of human civilisation, but there is still "a short window of time" in which to act.

A new study reveals the extent of global wildlife loss in recent decades, with lions an 'emblematic' example. Source: AP
A new study reveals the extent of global wildlife loss in recent decades, with lions an 'emblematic' example. Source: AP

The study, published in the peer-reviewed journal Proceedings of the National Academy of Sciences, calls the massive loss of wildlife a “frightening assault on the foundations of human civilisation”.

Professor Gerardo Ceballos, at the Universidad Nacional Autónoma de México, who led the research, said: “The situation has become so bad it would not be ethical not to use strong language.”

The scientists found that a third of the thousands of species losing populations are not currently considered endangered and that up to 50 per cent of all individual animals have been lost in recent decades.

The devastating loss of wildlife includes a mix of rare and common species. Source: AP
The devastating loss of wildlife includes a mix of rare and common species. Source: AP

Detailed data is available for land mammals, and almost half of these have lost 80 per cent of their range in the last century.

Billions of animals have been lost as their habitats have become smaller with each passing year.

The scientists concluded that the figures "will obviously have serious ecological, economic and social consequences ... Humanity will eventually pay a very high price for the decimation of the only assemblage of life that we know in the universe."

Contributing factors include overpopulation, habitat loss, climate change and pollution. Source: AP
Contributing factors include overpopulation, habitat loss, climate change and pollution. Source: AP

Wildlife is dying out due to habitat destruction, overhunting, pollution, invasion by alien species and climate change.

But the research concludes that the ultimate culprit is "human overpopulation and continued population growth, and overconsumption, especially by the rich."

Whales are migrating to previously unoccupied regions, a sign that global warming is affecting ocean life as well as land mammals. Source: AP
Whales are migrating to previously unoccupied regions, a sign that global warming is affecting ocean life as well as land mammals. Source: AP

The researchers have pointed to the “emblematic” case of the lion, which was once found all over Africa, southern Europe, and the Middle East and parts of northewestern India.

The vast majority of those populations are now gone.

Earth’s five previous mass extinctions

  • End-Ordovician, 443 million years ago

A severe ice age led to sea level falling by 100m, wiping out 60-70 per cent of all species, mostly water-dwelling creatures.

  • Late Devonian, c 360 million years ago

A prolonged climate change event affecting life in shallow waters, killing 70 per cent of species including almost all corals.

  • Permian-Triassic, c 250 million years ago

More than 95 per cent of species perished, linked to mass volcanic eruptions in Siberia that caused devastating global warming.

  • Triassic-Jurassic, c 200 million years ago

Three-quarters of species were lost, again most likely due to another huge outburst of volcanism, leaving the Earth clear for dinosaurs to flourish.

  • Cretaceous-Tertiary, 65 million years ago

An giant asteroid impact on Mexico saw the end of the dinosaurs and ammonites. Mammals, and eventually humans, began to flourish.