We Are in the Middle of a Sixth Mass Extinction
People have heard the stories about dinosaurs and how they went extinct, but what many don’t know is that there is a sixth mass extinction already happening—right now. The history of the Earth is punctuated by five major periods of extinction, all caused by either intense ice ages, natural changes in the climate, volcanoes, or the infamous meteorite. Now, over the last 12,000 years, a sixth period of biodiversity die-off known as the Holocene Extinction has begun, and the main cause is humans.
Humans have inflicted a lot on the Earth since the beginning of civilization — things that plants and animals just aren’t prepared to handle. Dr. Sinervo, a professor of Evolutionary Ecology at UC Santa Cruz said, “The cause is us and all the carbon and methane released into the atmosphere, but also how we have chopped up the habitats of animals and plants so they are so much more vulnerable.” The far too high rate of overhunting, ocean acidification, and deforestation across the planet also contributes to the extremely high number of animal species that are going extinct. A recent study of 77 species of endangered land vertebrates showed that they lost 94% of their populations in just the last century. On top of this, over 400 vertebrate species have already gone extinct in the last 100 years —a level of extinction which should have taken over 10,000 years to happen. That’s just vertebrates — scientists estimate that within the next few human generations, nearly ¾ of all animal species will go extinct. This unnatural rate of extinction has rapidly increased due to climate change and the impact it is having on ecosystems all around the globe. Human systems and overconsumption are devastating the natural habitats of millions of species. For instance, intensive agriculture causes soil degradation, deforestation, and pollution, leading to a severe decrease in natural, wild spaces for species to live in. A study by the Natural History Museum shows that human land usage has destroyed or drastically changed over 70% of natural land while also taking up nearly ¾ of all natural freshwater sources. Stripping natural ecosystems of their homes causes species to depend on other ecosystems or even human societies for resources — this need to expand outside their natural habitat is what causes so many species to go extinct. Human overfishing, over-hunting, over-usage, overpopulation, and overconsumption are responsible for a current extinction rate that is anywhere from 100 to 1,000 times faster than the pre-human rate, and which will cause severe damage to the biodiversity of the Earth.
After the previous five mass extinctions, scientists say that it took several million years for the planet to recover. This is because the impact of losing millions of vital plants and animals is tremendous. Entire ecosystems have been wiped out or forced to completely change because of mass extinctions and the loss of the key species that lived in certain regions. The planet's ecosystem works on a system of interdependency. It’s like a jenga tower; when you remove even just one species, the tower becomes unstable. When you remove multiple species, the tower will collapse. If ecosystems lose enough species, they will be unable to function due to diminished genetic variability and resilience. An example of this is the damage done to the natural ecosystems of sea otters when they nearly went extinct due to overhunting. Sea otters are the natural predators of sea urchins, which naturally prey on kelp. Without the otters, urchins saw a significant increase in population, and the kelp became outnumbered, eventually leading to the extinction of the Steller’s sea cow that depended on kelp for food. The extinction of one species in an ecosystem can have a chain reaction that leads to the extinction of several others as the natural systems are thrown off balance. When ecosystems collapse and the Earth no longer has it’s biodiversity, it will have irreversible consequences on human society and welfare.
We are quickly heading towards biological annihilation. As climate change and all the causes of it continue to get worse and more damaging, the planet will continue to lose ecosystems and key species that are necessary for the overall survival and well-being of the only assemblage of life we know of in the universe. Steps must be taken now, in order to hopefully mitigate the future damage that’s already been set in stone. There are ways that humans can work to support and bring back biodiversity and hopefully, get back on track for a more healthy planet in the future. Some solutions that environmental organizations are working on and urging the government to implement include creating more wildlife reserves around the world, putting harsher laws and regulations on hunting and fishing, making changes to agricultural systems, and returning land back to natural ecosystems. Rewilding, or the process of returning land back to its wild state after human-caused damage was done to it, is another way to fight back against the destruction caused by humans. Doing things like reforestation and habitat restoration are crucial to giving natural ecosystems back the land and water they need to get back on their feet.