Has Our Wear and Tear on the Planet Pushed It Into a New Epoch?
A new assessment by two dozen leading scientists declares that it has
You've heard of the ice age and the dinosaur age. Now some scientists say we're entering — or have already entered — not just a new age but a new epoch, dubbed the Anthropocene or "human" epoch for all the damage humans have done to the planet.
Two dozen scientists writing in the journal Science argue that “human activity is leaving a pervasive and persistent signature on Earth.”
Some earlier epochs lasted millions of years. During an epoch in the Carboniferous Period that began roughly 350 million years, swamp forests flourished and produced massive coal deposits that we rely on for energy to this day. Dinosaurs ruled during the Cretaceous Period until a giant meteor wiped them out 66 million years ago, ushering in the Paleocene epoch. And what we call civilization developed in the Holocene epoch, a mere 11,700 years ago.
Humans, the scientists say, have pushed us into a new epoch by altering the planet’s geologic operating system.
Among the changes the scientists describe:
A sore earth. More than half the earth is covered by cities, mines, waste dumps, roads, and more. The authors write that our reach “is increasingly extending into the oceans,” where trawlers destroy sea-floor environments and pesticide and fertilizer runoff cause oxygen-depleted “dead zones.”
Plastic waste everywhere. Not only do we produce 300 million tons of plastic every year — about the same mass as all the 7.3 billion humans on earth together, according to the researchers — we have lined the earth’s surface and waters with organic polymers and plastic microbeads found in toothpaste and cosmetics.
Fallout from nuclear testing. If humans many centuries in the future are running field tests on mud and ice, the radioactive fallout from the early 1950s and 1960s will mark that geologic moment in time. Plutonium will persist in ice and sediment for the next 100,000 years before decaying to uranium and later to lead.
Climate change and global warning. The concentration of carbon dioxide in the atmosphere is now 35 percent higher than it was at its peak for the past 800,000 years. Sea levels are higher now than they’ve been in the last 115,000 years, and they're continuing to rise.
A troubling harvest. Synthetic fertilizers have doubled the nitrogen and phosphorus in our soil over the last century, interfering with the earth’s nitrogen cycle more than anything else in the last 2.5 billion years, according to the authors.
The sixth mass extinction. The authors report that “current trends of habitat loss and overexploitation, if maintained, would push earth into the sixth mass extinction event,” with the disappearance of more than 75 percent of all species on earth within several centuries. Wildlife is scrambling for a foothold in a smaller and smaller slice of the earth, with just 25 percent of land that’s not under ice considered wild, compared to 50 percent three centuries ago, according to the authors. The earth’s life has already survived five major extinctions, and the authors warn that this one “is probably already underway.”
Not ready for the history books yet
The authors are part of the “Anthropocene Working Group,” which will send their proposal for declaring a new epoch to the International Commission on Stratigraphy later in 2016. The commission would have to agree on the new epoch before we start rewriting any geology textbooks.
“We could be looking here at a stepchange from one world to another that justifies being called an epoch,” Colin Waters, principal geologist at the British Geological Survey and a study co-author told The Guardian.
“What this paper does is to say the changes are as big as those that happened at the end of the last ice age. This is a big deal.”