The long, slow explosion of the population bomb

Earth's sixth mass extinction event already under way, scientists warn

Nearly half of the 177 mammal species surveyed lost more than 80% of their distribution between 1900 and 2015.

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A “biological annihilation” of wildlife in recent decades means a sixth mass extinction in Earth’s history is already well underway and is more severe than previously feared, according to new research.

Scientists analysed both common and rare species and found billions of regional or local populations have been lost. 

They blame human overpopulation and overconsumption for the crisis and warn that it threatens the survival of human civilisation, although there remains a short window of time in which to act.

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Previous studies have shown species are going extinct at a significantly faster rate than for millions of years before, but even so extinctions remain relatively rare giving the impression of a gradual loss of biodiversity. 

The new work instead takes a broader view, assessing many common species which are losing populations all over the world as their ranges shrink, but remain present elsewhere.

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

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

The scientists found billions of populations of mammals, birds, reptiles and amphibians have been lost all over the planet, leading them to say a sixth mass extinction has already progressed further than was thought.

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

But the ultimate cause of all of these factors is “human overpopulation and continued population growth, and overconsumption, especially by the rich”, say the scientists, who include Prof Paul Ehrlich, at Stanford University in the US, whose 1968 book The Population Bomb is a seminal, if controversial, work.