Posted On 14 Jun 2011
The Anthropocene is our time.
At least for old people with my temper of mind, this comes as a shock. For about the last half century I have considered myself an environmentalist. I have taken comfort sharing Henry David Thoreau’s famous belief that “in wilderness is the preservation of the world.”
Wilderness has become increasingly irrelevant. There are few ecosystems left in which humankind does not play a significant role. This strikes me as absurd.
How can it be? How can one species of animal who has been around for less than 1% of 1% of our planet’s history already be reshaping it, in the words of The Economist [28 May 11], “on a geological scale-but at a far-faster-than geological speed?”
Our use of fossil fuels, our scientific breeding of plants and animals, and the second agricultural revolution have led some to estimate that humans now play a significant role in nearly 90% of the Earth’s plant activity. Artificially fixing nitrogen [see http://dennis-bradford.com/997/the-second-agricultural-revolution/] has enabled human population to soar. Whereas there were only about 1 billion of us just two centuries ago, there may soon be 10 billion.
Hundreds of millions of us live in river deltas that are eroding away faster than they can be replenished. Why? 50,000 large dams in the last 50 years have dramatically cut sediment flow.
Just one large engineering project (namely, the Syncrude mine in the Athabasca tar sands) is displacing twice as many tons of earth as the amount of sediment that flows down all the earth’s rivers in a year!
One reason such facts are shocking is that we had gotten used to thinking of ourselves as rather insignificant observers of the natural world. Astronomers still think that way, but earth-system scientists do not. After all, Copernicus displaced our favorite planet from the center of the world. Hutton opened up deep geological time to aeons that dwarf the present. Darwin relegated us to a single small twig on the bush of life.
Earth-system scientists understand that we have changed the way Earth works. Its systems, such as its carbon and nitrogen systems, are now working differently.
The Holocene epoch, which was a 10,000-year-old span of the Quarternary period, was an unusually stable and clement epoch. The Quarternary period itself was distinguished by Earth’s regularly slipping into and out of ice ages. The Quarternary period is the latest part of the Cenozoic era that saw the opening of the North Atlantic, the rise of the Himalaya mountain range, and the abundance of mammals and flowering plants.
The Anthropocene, which means “the recent age of man,” has just begun. Instead of being largely irrelevant, human activity is now central to how Earth should be understood. For example, without our activity, the Holocene would have eventually ended in a new ice age.
Nobody is sure how the Anthropocene will end. In fact, nobody has a clue what the future holds.
It’s possible that the Anthropocene will end with our extinction: either directly or indirectly, global warming will wipe us all out.
On the other hand, it’s possible that, by using more solar or nuclear energy, we may figure out how to tinker with Earth’s systems to benefit us and prolong the end of the Anthropocene. For example, we might change the hydrologic cycle with massive desalination plants or speed up the carbon cycle by reducing atmospheric carbon dioxide.There’s no necessary reason why we couldn’t voluntarily reduce the numbers of humans back to 1 billion, which is something we already understand how to do. (I think we should.)
Personally, I am neither optimistic nor pessimistic. As a matter of fact, the older I get the less I worry about the future at all! After all, since evidence about the future is impossible to acquire, it’s epistemologically silly to speculate.
Furthermore, life always occurs in the present. I have no complaints whatsoever about the present.
Still, though, I occasionally worry that future humans won’t be as fortunate as we all have been. The eternal domain of Being will not change, but Earth will– and those changes may not be beneficial to sentient beings.