As in all things, the bacteria got there first. One tiny cell built inside of itself a new pigment, a brilliant green thanks to its ability to absorb only certain colors in the light of a younger, weaker Sun. The pigment – dubbed chlorophyll by animals that rely on this one cell’s innumerable descendants to power name-giving brains – channeled the energy in sunshine to split the waters of Earth’s early oceans. The cell took in carbon dioxide, paired it with once watery hydrogen, and made food. In the process out bubbled a flammable gas that made life as we know it possible: oxygen.
illustration Doug Chayka
These bacteria were the first geoengineers – large-scale manipulators of the planetary environment. More than 2 billion years ago, these tiny cells ensured that the atmosphere of the planet became dominated equally by geologic processes and biologic ones, off-gassing and emanations from life combining to wreathe the planet in a particular mix of gases that then came to determine all the fundamental cycles: air, earth, fire, water. Once the microbes had reconfigured atmospheric chemistry, they set about changing global temperatures. Snowball Earth morphed into hothouse Earth and back again, with an assist from the steady march of plate tectonics across the surface of the globe.
Now we humans are doing it again. From deep beneath the ground, where we busily hollow out yawning cavities in pursuit of fossil fuels, to the skies far above, where CO2 molecules released by our incessant burning will trap heat for longer than our species has walked the planet, we are driving the systems we like to think of as natural. And just as climate change marked the turning points in the two most recent epochs – the cold, wintry Pleistocene and the long summer of the Holocene when human civilization was born and flourished – so too our man-made climate change merits a new epochal designation.
Welcome to the Anthropocene.
That’s the name geologists and other scientists have come up for this new era: The Age of Man. We are the first life to transform this planet consciously, terraforming terra herself as a result of our actions, mostly unwittingly to date.
It is an old idea. All the way back in 1874, George Perkins Marsh, arguably the first true environmentalist in the United States, wrote a book entitled The Earth as Modified by Human Action. For more than a century geologists and others have been coming up with names for this new epoch of human impacts: Anthropozoic, Psychozotic, Noosphere. Paul Crutzen, who won the Nobel Prize for predicting the ozone hole, popularized the latest iteration.
This new era is certainly older than Crutzen’s term for it, though there remains much debate about when, exactly, the Anthropocene may have begun. It might have been when James Watt invented a practical steam engine some 250 years ago, and ushered in the age of prolific coal burning, soon to be joined by the age of oil. Or it could be older yet, maybe 50,000 years, and linked to the start of humanity’s cascade of large animal extinctions, starting with our fellow hominids. Or maybe it should be pegged to the Neolithic Revolution some 10,000 years ago, when humanity began to reshape the ground cover of the Earth’s continents with the advent of farming. Regardless, the Anthropocene is a rounding error in the 4.5-billion-year history of the planet.
In the end, there may not be much left of our civilization in the rock record. After all, abandoned areas of New Orleans reverted to subtropical jungle within seven years of Hurricane Katrina’s devastating landfall. Our most sprawling cities will leave little mark, ground back into mineral dust and, ultimately, rock. The future may know us instead by a thin layer of plutonium and other rare radioactive isotopes from nuclear weapons and power plants as well as spacecraft accidents, like the thin layer of iridium that tells the tale of the dinosaur killer. The record of our presence might be written in sediment laced with chemicals and plastics unknown previously and not deposited by rivers or natural dams; some redistributed minerals, metals and a sudden increase in global nitrogen; an odd shift in the fossils of pollen grains favoring grassy, seed-bearing species.
Most likely, we will be known through our imprint on the atmosphere, a mark that we make more indelible with each passing day. If life in the future doesn’t like the climate a century, a millennium, or even tens of thousands of years from now, we will be to blame.
Such knowledge fuels the anxiety of this new epoch. Are there too many people? Is the food we eat destroying us and the planet? Is our own technology transforming us into atomized automatons, mindlessly clicking links all alone? In the competitive thrust of modern civilization, what have we lost? These are all important questions, but there is a more important one lurking behind them all: Are we ready to accept the responsibility of managing this planet?
As the late astronomer Carl Sagan famously observed: Everyone who has ever lived, all the knowledge ever known, everything anyone has ever loved lives only on this incredibly small planet in the vastness of space and time. We are not the first species to geoengineer the planet, but we are the first to do so knowingly, though often thoughtlessly. We therefore have the option of doing it more thoughtfully, managing the planet to ensure that our civilization and as many of our fellow travelers as possible continue this ride on Spaceship Earth. The idea is to make an enduring Anthropocene, one that merits its place in geologic time, rather than signaling a minor blip in the long life of our planet.
This is not the end of the world. This is just the end of the world as we have known it.
David Biello, an editor at Scientific American, is working on a book about the Anthropocene to be published by Scribner.
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