A hippo in Okavango Delta National Park, Botswana.
Credit: Buena Vista Images / Stone / Getty

Scientists from around the world issued a stark warning to humanity Tuesday in a semi-annual report on the Earth’s declining biodiversity, which shows that about 60 percent of mammals, birds, fish and reptiles have been wiped out by human activity since 1970.

The World Wildlife Fund’s Living Planet Index details how human’s uncontrolled overconsumption of land, food and natural resources has eliminated a majority of the wildlife on the planet—threatening human civilization as well as the world’s animals.

“We are sleepwalking towards the edge of a cliff,” Mike Barrett, executive director of science and conservation at WWF, told the Guardian. “If there was a 60 percent decline in the human population, that would be equivalent to emptying North America, South America, Africa, Europe, China and Oceania. That is the scale of what we have done.”

Killer whales were named as one species that is in grave danger of extinction due to exposure to chemicals used by humans, […]