Human intervention has triggered a new geological epoch

You don’t need to be paying much attention to the world around you to know that humans are having a massive influence on the planet, but our influence is now on the way to being officially recognised in geologic terms. The 11,700-year-old geological Holocene epoch has ended, scientists say, and we’re now living in the Anthropocene: an era defined by humanity’s influence on the world around us.

In fact, unless you’re over the age of 66, you’ve always been living in it. A 35-strong team of international researchers from the Working Group on the Anthropocene voted 30-3 (two were absent) in favour of the epoch shift, and the starting date is 1950. The date isn’t random: it matches when the first nuclear tests created a new stratum in the planet’s surface.

Actually, it won’t necessarily be nuclear tests that ended the Holocene. Humanity’s impact on the planet is so great that we’re left “spoiled for choice” in terms of which particular signal to choose. Plastic pollution, soot from power plants, concrete and even domestic chicken bones were considered possible contenders. “The radionuclides are probably the sharpest – they really come on with a bang,” said the Working Group’s chair Jan Zalasiewicz, of the University of Leicester. “But we are spoiled for choice. There are so many signals.”

Now that the vote has been done, we’ll see a few years of site sampling to figure out the best Global Standard Stratigraphic Age (GSSA) to date the start of the Anthropocene, which will then be presented to the International Commission on Stratigraphy. It would then need ratification from the Executive Committee of the International Union of Geological Sciences.

So it’s not official yet, but Zalasiewicz believes the team has a “pretty good case” to present.

“The significance of the Anthropocene is that it sets a different trajectory for the Earth system, of which we of course are part,” he explained. “If our recommendation is accepted, the Anthropocene will have started just a little before I was born. We have lived most of our lives in something called the Anthropocene and are just realising the scale and permanence of the change.”

In other words, geologically at least, there will be no denying the influence mankind has had on the planet. And it’s a hard one to put a positive spin upon, no matter how you frame it.

Images: James Cridland and CBTO used under Creative Commons