The Earth’s wild species are in crisis. Animal populations have declined by an average of almost 70 per cent since 1970—a drop caused entirely by human activity. But what exactly is behind this decline, has it happened before, and what can we do to protect wildlife for the future?
The World’s Mass Extinction Events
There have been five mass extinction events before, but none of them were caused by a single species. The first happened about 443 million years ago, and was triggered by an ice age. It wiped out 60-70 per cent of all species, most of which were ocean dwellers, such as trilobites, reef-building brachiopods, and some bryozoans.
The second came 252 million years ago and decimated many marine species, including almost all corals. It was caused by climate change.
The third—and so far largest—mass extinction event came 250 million years ago and wiped out 95 per cent of all species, including most marine species as well as insects and other land-based animals. Scientists believe that global warming associated with huge volcanic eruptions was the cause.
In the late Triassic period, 200 million years ago, there was a fourth mass extinction event, again thought to be triggered by enormous volcanic eruptions. It wiped out many marine species including sponges, bivalves, and cephalopods as well as insects and vertebrates.
The fifth was 65 million years ago and was triggered by an asteroid hitting the planet. It killed many marine and land-dwelling species, including all non-avian dinosaurs.
As for the sixth, well, we may just be living through it now.
Are We in the Sixth Mass Extinction?
Outside of mass extinction events, there have always been extinctions but scientists agree that today’s rate of extinction is hundreds, perhaps thousands, times greater than the baseline rate. Devastatingly, that means we may be entering the world’s sixth mass extinction event
What is Driving Extinctions?
Today, there are about eight million species on Earth, and at least 15,000 of them are threatened with extinction. An analysis of 2,000 global studies found multiple significant drivers, with most connected to the kinds of foods we eat. The leading causes are:
- Habitat destruction
- Hunting
- Toxic pollution
- Climate change
Habitat Destruction and Extinctions
It is obvious that if we destroy habitats, we destroy their inhabitants. Currently almost six million hectares of forest are destroyed every year, and the leading drivers of this are the production of beef, soy to feed farmed animals, and palm oil. It is clear we need to protect the land and to return as much to nature as possible. Farming animals for meat, milks, eggs, and fish uses 83 percent of farmland but gives us just 18 per cent of our calories and 37 per cent of our protein. If we switched to a plant-based diet we would free up three quarters of the land currently used, and could reverse the biodiversity crisis.
Hunting, Fishing and Extinctions
While the biggest impact on wild species is habitat destruction, “human hunters actively killing animals are still making matters worse”, says science writer Matt Gross. He cites the world’s first large-scale study of hunting-induced declines, which showed in areas close to humans, mammals are reduced to just 17 per cent of their natural population and birds to 42 per cent. As for aquatic species, the fishing industry kills trillions of animals per year, with one third of marine populations currently “over-exploited”—that means, we are killing quicker than the fish can reproduce. And then there is “by-catch”—the millions of animals like whales, dolphins, turtles, and rays who are caught and killed alongside target fish.
Toxic Pollution and Extinctions
One problem with farming 70 billion animals a year for human consumption is that we have nine times more mouths to feed than if humans just ate plants directly. To feed all those animals, vast amounts of crops must be grown and similarly vast amounts of toxic chemicals are used to do that. Pesticide use has more than doubled since 1990 so it is little surprise that the global insect population is declining by two per cent per year. Their loss significantly impacts populations of mammals, amphibians, fish, and birds. On top of that, the toxic waste produced by those billions of farmed animals also drives mass die-offs of aquatic animals.
Climate Change and Extinctions
As our world’s climate changes, wild animals are put under severe pressure as we know from previous mass extinction events. One meta-analysis found that extinctions will accelerate rapidly if global temperatures exceed 1.5°C, which is now very likely to happen. Depending on how quickly and strongly we act to halt the breakdown of our climate, we could lose one-third of species globally. Some will be due to loss of habitat to rising waters, other species will lose their food source, and there will be many who simply are unable to survive in different climatic conditions. The leading drivers of climate change are fossil fuel use and the consumption of meat, fish, eggs, and dairy.
How to Stop Wildlife Extinctions
- The biggest thing we can do is to reduce the amount of land used to produce our foods so it can be returned to nature. That means eating plant-based.
- Avoiding hunting and fishing, and buying associated products, such as trophies or fish products, such as fish oils.
- Reduce the amount of toxic chemicals on the planet by buying organic wherever possible, and not using chemicals in our own yards and gardens.
- Reduce fossil fuel use by eating plant-based, reducing air travel, buying less “stuff”, and choosing public transportation over car use.
It is devastating to learn of these serious declines in wild populations and to notice the loss of wildlife and birdsong within our own communities. There is much we can do to help change this situation, and each of us has a powerful part to play. But it does require us to change how we eat.
