September 12, 2016 6:17 AM EDT

As Geological epochs have come and gone throughout Earth’s vast history, shifts have often correlated with large-scale global changes like ice ages and mass extinctions. An asteroid hits the planet, wiping out the dinosaurs, and the Cretaceous period becomes the Tertiary. Until now, life on Earth–including us late-arriving Homo sapiens–was along for the ride. But on Aug. 29, some scientists at a meeting of the International Union of Geological Sciences (IUGS) in South Africa said human activity has grown so powerful that it is forcing a change of the geological calendar: Earth has entered a new epoch, called the Anthropocene, defined by humans and our effect on the planet.

For 12,000 years, we lived through an epoch known as the Holocene, which provided a stable and relatively warm climate that allowed humans to develop everything from agriculture to atomic power. But that success remade the planet we live on through widespread deforestation, overfishing of the oceans, the extinction of countless species and the altering of the planet’s climate through the emission of greenhouse gases. Most telling is the spread of radioactive material across Earth since 1950 as a result of the testing of nuclear bombs. Humans brought an end to the Holocene quickly–no other geological epoch lasted fewer than several million years.

The IUGS gets the final vote on the geological calendar, and while scientists in its working group on the Anthropocene overwhelmingly recommended the new designation at the South Africa meeting, it has yet to be confirmed. But momentum has been building behind the Anthropocene for some time. Paul Crutzen, a Nobel Prize–winning chemist, first described this human-influenced era more than a decade ago with a focus on climate change. The downside of human influence should be obvious–we’re not just changing our planet but destroying it. Yet there’s a silver lining. If we are powerful enough to cause these problems, we might also solve them. “Unless there is a global catastrophe,” Crutzen wrote in the journal Nature, “mankind will remain a major environmental force for many millennia. A daunting task lies ahead.”

–JUSTIN WORLAND

This appears in the September 12, 2016 issue of TIME.

Write to Justin Worland at justin.worland@time.com.

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