By Matthew Dunn

Humans have damaged the Earth's ecosystems so badly that we are facing the biggest mass extinction since the dinosaurs were removed from the planet 66 million years ago.

And there is very little we can do because this era of "biological annihilation" is already underway, scientists have warned.

According to a study published in the journal Proceedings of the National Academy of Sciences, the sixth mass extinction is currently underway, with fears three-quarters of all species could disappear in the coming centuries.

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And while the previous five mass extinctions the Earth were caused by natural phenomena, humans are the contributing shift for the current biological annihilation.

Although some might view the findings as nothing more than alarmism, lead researcher Gerardo Ceballos said avoiding such strong language wouldn't be ethical as the problem is far more severe than what was previously thought.

Assessing many common species around the globe, scientists found up to 50 per cent of all individual animals have been lost in recent decades.

They also found that about 30 per cent of all land vertebrates - mammals, birds, reptiles and amphibians - are not currently considered endangered, despite a rapid decline in populations.

"Population extinctions, however, are a prelude to species extinctions, so Earth's sixth mass extinction episode has proceeded further than most assume," the report read.

"The resulting biological annihilation obviously will have serious ecological, economic and social consequences," the report concluded.

"Humanity will eventually pay a very high price for the decimation of the only assemblage of life that we know of in the universe."

Researchers did say it is possible to halt the decline, the outlook does not look positive.

"All signs point to ever more powerful assaults on biodiversity in the next two decades, painting a dismal picture of the future of life, including human life," researchers wrote.

Overhunting, invasion by alien species, climate change and toxic pollution were all contributing factors in wildlife dying out.

The last mass extinction saw the end of the dinosaurs. Photo / 123RF
The last mass extinction saw the end of the dinosaurs. Photo / 123RF

However, the ultimate driver is "human overpopulation and continued population growth, and overconsumption, especially by the rich".

Author of the 1968 book The Population Bomb and study researcher professor Paul Ehrlich said the serious warning in the report should not be dismissed.

"The time to act is very short," he told The Guardian.

"It will, sadly, take a long time to humanely begin the population shrinkage required if civilisation is to long survive, but much could be done on the consumption front and with 'band aids' - wildlife reserves, diversity protection laws - in the meantime."

What were Earth's previous mass extinctions?

End-Ordovician - c 443 million years ago

The third largest extinction in Earth's history saw a severe ice age cause sea level falling by 100m, which wiped out 60-70 per cent of all species - most of life on Earth was in the sea.

Late Devonian - c 360 million years ago

Three quarters of all species on Earth became extinct after prolonged climate change event, with shallow seas the worst affected areas. Reefs were also hard hit, which nearly saw all corals disappearing.

Permian-Triassic - c 250 million years ago

Aptly nicknamed "the great dying", the third mass extinction saw 96 per cent of species dying out. Massive volcanic eruptions in Siberia were strongly linked to the savage episode of global warming responsible for the extinction.

Triassic-Jurassic - c 200 million years ago

Climate change, an asteroid impact and flood basalt eruptions have all been blamed for wiping out three-quarters of the species on Earth.

Cretaceous-Tertiary - 65 million years ago

The most famous mass extinction, which saw the death of dinosaurs from a giant asteroid impact.