The list of human impacts on the planet is a long one. We move more earth and stone than all the world's rivers. We are changing the chemical composition of the atmosphere largely by burning fossil fuels and cutting down forests. And we now consume at least a quarter of all the sun's energy that plants have turned to food.

That's why geologists have come up with a new name for this new era in the planet's 4.5 billion year history: the Anthropocene, or the "age of man." Future rocks will record a shift from the preceding era, the Holocene, meaning "entirely recent." Our new era may be a scant 250 years old, dating to James Watt's steam engine. Or it could stretch back to the dawn of agriculture. Either way, it’s indisputable that it’s here, now.

Photosynthetic microbes filled the atmosphere with oxygen billions of years ago but they renovated the planet without awareness. We are thus the only life form that both created a geological era and became conscious of doing it. Hence our creation of events like Earth Day. In the hope that the Anthropocene doesn’t end too soon.

—David Biello

[The above text is a transcript of this podcast.]