geology

Is human activity altering the planet on a scale comparable to major geological events of the past? Scientists are now considering whether to officially designate a new geological epoch to reflect the changes that homo sapiens have wrought: the Anthropocene.

The Holocene — or “wholly recent” epoch — is what geologists call the 11,000 years or so since the end of the last ice age. As epochs go, the Holocene is barely out of diapers; its immediate predecessor, the Pleistocene, lasted more than two million years, while many earlier epochs, like the Eocene, went on for more than 20 million years. Still, the Holocene may be done for. People have become such a driving force on the planet that many geologists argue a new epoch — informally dubbed the Anthropocene — has begun.

In a recent paper titled “The New World of the Anthropocene,” which appeared in the journal Environmental Science and Technology, a group of geologists listed more than a half dozen human-driven processes that are likely to leave a lasting mark on the planet — lasting here understood to mean likely to leave traces that will last tens of millions of years. These include: habitat destruction and the introduction of invasive species, which are causing widespread extinctions; ocean acidification, which is changing the chemical makeup of the seas; and urbanization, which is vastly increasing rates of sedimentation and erosion.

Human activity, the group wrote, is altering the planet “on a scale comparable with some of the major events of the ancient past. Some of these changes are now seen as permanent, even on a geological time-scale.”