Ice ages, volcanic eruptions, and asteroids have a new companion: human beings.

Scientists are warning that the world has entered its sixth mass extinction — an event when a majority of species on Earth die off; and unlike past episodes, the cause is not some suddenly overwhelming natural phenomenon.

Instead, it’s the cumulative activity of humans.

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In a new study published in the Proceedings of the National Academy of Sciences, a team of researchers argue that a “biological annihilation” is underway that represents a “frightening assault on the foundations of human civilisation.”

“The situation has become so bad it would not be ethical not to use strong language,” Gerardo Ceballos, lead author of the study, told The Guardian.

The team studied species across the animal kingdom and found that billions of regional populations have been lost and that 50% of all individual animals have died in recent decades.

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The primary driver of this disintegration of life is human overpopulation and consumption, according to the authors.

Animals are further threatened by “habitat destruction, overhunting, toxic pollution, invasion by alien species, and climate change,” according to The Guardian.

But it’s the sheer appetite of humanity that’s most to blame.

Each year, the amount of resources consumed by humans increases, according to the Global Footprint Network. For this rate of consumption to be sustainable, humanity would need multiple Earths to supply resources like food, wood, and water.

But since that’s implausible, wildlife has a harder time replenishing to stable levels each year. This pressure is clearly seen in the shrinking habitat range of most animals.

Between 1900 and 2015, nearly half of the 177 of mammal species that were studied lost 80% of their historic ranges.

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The situation isn’t any better underwater.

More than 90% of all fish populations are being harvested at dangerous levels.

While the species approaching extinction are the most immediate victims, humans will ultimately be greatly affected, according to the authors.

“The resulting biological annihilation obviously will have serious ecological, economic and social consequences,” they conclude the report. “Humanity will eventually pay a very high price for the decimation of the only assemblage of life that we know of in the universe.”

For this decline to be stemmed, immediate action has to be taken.

First, “band-aid” efforts like creating wildlife preserves, enacting tougher environmental regulations, restoring ecosystems, and more have to be undertaken.

Progress on this front is uneven. Last year, the US designated the largest marine reserve in the world and countries like South Africa are doing a good job at protecting endangered animals.

Further, this year’s World Oceans Day on June 8 earned thousands of protections for marine life.  

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But elsewhere, habitat destruction is accelerating. In Brazil and Paraguay, for instance, industrial agriculture is leading to the rapid depletion of rainforests. China, meanwhile, is seeing large portions of its land turn to desert.

More broadly, the authors argue, human consumption has to come down to more manageable levels and the human population has to eventually peak. By 2100, the human population is expected to explode to 11 billion people.   

Providing a decent standard living by then will depend on if humans summon the will to act now.