Earth will never be the same.
The phrase “mass extinction” typically conjures images of the asteroid crash that led to the twilight of the dinosaurs.
Upon impact, that 6-mile-wide space rock caused a tsunami in the Atlantic Ocean, along with earthquakes and landslides up and down what is now the Americas.
Although it may not be obvious, another devastating mass extinction event is taking place today – the sixth of its kind in Earth’s history.
A 2017 study found that animal species around the world are experiencing a “biological annihilation” and that our current “mass extinction episode has proceeded further than most assume.”
Here are 12 signs that the planet is in the midst of the sixth mass extinction, and why human activity is primarily to blame.
1. Insects are dying off at record rates. Roughly 40 percent of the world’s insect species are in decline.
A 2019 study found that the total mass of all insects on the planets is decreasing by 2.5 percent per year.
If that trend continues unabated, the Earth may not have any insects at all by 2119.
“In 10 years you will have a quarter less, in 50 years only half left, and in 100 years you will have none,” Francisco Sánchez-Bayo, a coauthor of the study, told The Guardian.
That’s a major problem, because insects like bees, butterflies, and other pollinators perform a crucial role in fruit, vegetable, and nut production.
Plus, bugs are food sources for many bird, fish, and mammal species – some of which humans rely on for food.
2. Earth appears to be undergoing a process of “biological annihilation.” As much as half of the total number of animal individuals that once shared the Earth with humans are already gone.
A 2017 study looked at all animal populations across the planet (not just insects) by examining 27,600 vertebrate species – about half of the overall total that we know exist. They found that more than 30 percent of them are in decline.
Some species are facing total collapse, while certain local populations of others are going extinct in specific areas. That’s still cause for alarm, since the study authors said these localised population extinctions are a “prelude to species extinctions”.
So even declines in animal populations that aren’t yet categorized as endangered is a worrisome sign.
3. More than 26,500 of the world’s species are threatened with extinction, and that number is expected to keep going up.
According to the International Union for Conservation of Nature Red List, more than 27 percent of all assessed species on the planet are threatened with extinction.
Currently, 40 percent of the planet’s amphibians, 25 percent of its mammals, and 33 percent of its coral reefs are threatened.
The IUCN predicts that 99.9 percent of critically endangered species and 67 percent of endangered species will be lost within the next 100 years.
4. A 2015 study that examined bird, reptile, amphibian, and mammal species concluded that the average rate of extinction over the last century is up to 100 times as high as normal.
Elizabeth Kolbert, author of the book The Sixth Extinction, told National Geographic that the outlook from that study is dire; it means 75 percent of animal species could be extinct within a few human lifetimes.
5. In roughly 50 years, 1,700 species of amphibians, birds, and mammals will face a higher risk of extinction because their natural habitats are shrinking.
By 2070, 1,700 species will lose 30 percent to 50 percent of their present habitat ranges thanks to human land use, a 2019 study found.
Specifically, 886 species of amphibians, 436 species of birds, and 376 species of mammals will be affected and consequently will be at more risk of extinction.
6. Logging and deforestation of the Amazon rainforest is of particular concern.
Roughly 17 percent of the Amazon has been destroyed in the past five decades, mostly because humans have cut down vegetation to open land for cattle ranching, according to the World Wildlife Fund.
Some 80 percent of the world’s species can be found in tropical rainforests like the Amazon, including the critically endangered Amur leopard.
Even deforestation in a small area can cause an animal to go extinct, since some species live only in small, isolated areas.
Every year, more than 18 million acres of forest disappear worldwide. That’s about 27 soccer fields’ worth every minute.
In addition to putting animals at risk, deforestation eliminates tree cover that helps absorb atmospheric carbon dioxide. Trees trap that gas, which contributes to global warming, so fewer trees means more CO2 in the atmosphere, which leads the planet to heat up.