We humans are having such a dramatic impact on our planet that some leading scientists think the current era needs a new name. We're no longer in the Holocene epoch, they say. We're now well into what they are calling the Anthropocene.
This planet is being changed by human activities in ways that will continue to alter Earth for millions of years. The most obvious example is global climate change precipitated by the release of greenhouse gases from fossil fuels, but there are many more, some so obvious it's hard to think of them as insidious threats to our environment.
But they are indeed, according to the leader of the Anthropocene movement, Nobel laureate Paul J. Crutzen, who is said to have coined the word during a science meeting in 2000. Crutzen, former chief of atmospheric chemistry at the Max-Planck-Institute in Germany and now a part-time professor at the Scripps Institution of Oceanography in San Diego, is out with a new paper that leads off with a provocative question: "Are Humans Now Overwhelming the Great Forces of Nature?"
The paper, published by the Royal Swedish Academy of Sciences in the current issue of the journal Ambio, begins with this warning:
"Global warming and many other human-driven changes to the environment are raising concerns about the future of Earth's environment and it's ability to provide the services required to maintain viable human civilizations. The consequences of this unintended experiment of humankind on its own life support system are hotly debated, but worst-case scenarios paint a gloomy picture for the future of contemporary societies."
Pretty scary stuff, but Crutzen and his co-authors have done their homework. In fact, they argue that about the only thing that might head off a global human catastrophe is some other catastrophe, like "a meteorite impact, a world war or a pandemic." Here are just a few of their points, in their own words:
A sticking point on labeling this a new epoch is disagreement over when the Anthropocene actually began. Some argue it began when our ancestors abandoned hunting and gathering and took up farming. Huge swaths of land were cleared and the trees burned, launching the rise in greenhouse gases.
A forester once told me that many years ago it would have been possible to walk from the California coast to the Mississippi River and only occasionally be forced to step out of the shade of an oak forest. Nearly all of that is gone now.