If we look into the past, about 56 million years ago, we find a moment, a thin line in the geologic record where the course of life on Earth was altered. Carbon in the atmosphere soared. Global temperatures rapidly rose by 6°C. Weather got more extreme and huge numbers of our planet life forms disappeared forever. The Palaeocene Eocene Thermal Maximum (PETM) is one of the most radical climate events ever unearthed. The mass extinction that followed was triggered, at least in part, by an injection of greenhouse gases into the air.
Extinction is a fact of life. But the crisis we currently face is of a scale never before seen since our species arrived on Earth – and this time, it’s because of us. Today, one million species are threatened with extinction. While one extinction is a tragedy, a million risks being just another statistic. So let’s break down what this really means.
One in eight non-microbial life forms on Earth could disappear, many within decades.
For mammals alone, it will take millions of years to recover from the losses they are predicted to endure over the next half-century.
That future is hard to imagine, but we can see what’s happening right now.
Things are changing on land too:
As diverse as human populations have become, our food is becoming less so. Around 75 per cent of what we eat comes from just twelve plants and five animal sources.
More than 550 breeds of mammals use for food and agriculture throughout history have already gone extinct.
These land changes altogether have left half a million terrestrial species without enough habitat to survive long term.
As trade and travel expand, we’re moving plants and animals around too. Some countries are seeing as much as 70% more invasive species than in 1970.
No known disease has damaged global biodiversity more.
We’ve also spread our garbage around the world.
Along with fertilizers, land clearing and crop production account for a quarter of our greenhouse gas emissions. Those emissions have doubled since the 1980s, rising average global temperatures by at least +0.7°C which doesn’t sound like much, but at just 2°C of warming, 1 in 20 extinctions will be directly caused by climate change.
Plants and plankton sequester 5.6 billion tonnes of CO2 every year. That’s 60 per cent of global fossil fuel emissions, removed by species we currently threaten.
The long list of plants and animals that disappeared 56 million years ago during the PETM owe their demise almost solely to carbon and climate change, but the threats today to natural ecosystems go far beyond climate. Diseases, land use, and pollution also threaten our planet’s plants and animals.
We’re animals too, and our actions have already affected our own future. Yet, if this were to all disappear, if one million species were to go extinct and we were to change our planet to this extent, in the scale of geologic time, should we look back on this moment, the billions of us would be a paper-thin memory in the long history of Earth. It’s up to us to decide if the world we know today gets to be more than that in the future.
Wow, guys. Wow. Am I right? Most of what you just read comes from the biggest review of life in Earth that’s ever been conducted. Over 400 experts from 50 countries looked up at 15,000 sources to give us this big pile of bad news. But they also provided plenty of opportunities to make it better. If you want to know more of what you can do to help the natural world, check the links below: