Earth in Human Hands Read online

  In this emerging scheme, we are nothing. Or at least nothing special. In Pale Blue Dot, Carl Sagan writes:

  The Apollo pictures of the whole Earth conveyed to multitudes something well known to astronomers: On the scale of the worlds—to say nothing of stars or galaxies—humans are inconsequential, a thin film of life on an obscure and solitary lump of rock and metal.

  Carl referred to these successive scientific blows to the human ego as “the great demotions,” and he described this progressive shedding of our infantile, self-important pretentions as a thrilling liberation from inherited delusions and a signature achievement of science.

  Now—what? We’re changing our minds? In declaring the Anthropocene to be an epoch of Earth history for which we are responsible, are we reversing this grand history of great demotions and giving ourselves a “great promotion” which places us back at the center of the story?

  Well, sort of—and yes, this is indeed disturbing. Yet the point of science, as Carl liked to remind us, is not to comfort ourselves with feel-good stories, but to keep finding new ways to pull back the veils of delusion and see things as they really are, and then to deal honestly with whatever we learn. With the quote that begins this chapter, he admonished us to reject the old easy answers, the egotistical narratives in which we were central to the story of Earth. Strangely, we can now turn this dictate around to argue the opposite point. If we want to grasp the way things really are on Earth today, then we need to acknowledge our special part. Science has repeatedly revealed to us that we are not unique or special—except, guess what. We are. Once, in order to grasp the vastness of the cosmos and the peripheral nature of our reality, we had to awaken from naïve ego- and geo-centric dreams. Now we have to come to grips with our own significance. We’ve entered an age where we are radically changing the plotline, to the point where we cannot see nature clearly if we insist on ignoring our own growing role. Not only that but, as far as we know, Earth is the only place in the universe with life and intelligence. That may soon change, but for all we know we could be determining the future of all life. The delusion we may need to shed is that we can avoid the responsibility of, in some way, running this planet. We may be uncomfortable in this role, but it certainly won’t help to deny it.

  Our world is changing in unprecedented ways because of a new dynamic, a new set of processes, a new motive force we are obliged to examine. We are that force, and this puts us right back in the center. The term paradigm shift is used far too frequently to describe changing ideas in science. However, the reintegration of human activities into our understanding of the “natural” world is worthy of this term.

  We’ve been taught that science is objective, value neutral, and depersonalized. In order to study nature clearly, we’re supposed to remove ourselves from the frame, tiptoe out of the picture, brush over our tracks, and make ourselves invisible. Yet in our new Anthropocene science, the boundaries are not so clean. As we observe the world, the lens is part of the photograph. As I’ve discussed, climate modeling is hard enough even when the modelers are not themselves part of what is being modeled. Ecologists, accustomed to studying various biomes, or communities of organisms existing in specialized environments, are now studying “anthromes,” where human activities have become part of ecological systems. Rather than simply ignore or deplore croplands, rangelands, parks, cities, and managed forests, we can put them in our maps and models and decide how we want to integrate them into the world.

  The triumphant successes of Enlightenment-driven science have drilled into our oversize, skeptical heads the notion that we cannot see ourselves as privileged in any way, that any stories in which our species is somehow special or pivotal are not to be trusted. There’s some irony here, as the very success of this hyper-Copernican worldview has sown the seeds of its downfall, or at least its necessary revision. When Galileo stuck lenses on a tube and pointed his first crude telescope at the heavens, what he saw did not comport with the dominant, and biblically official, cosmology. His observations that Jupiter was accompanied by its own moons and that Venus was orbiting around the Sun could not be reconciled with an Earth that was the center of it all. In the resultant scientific revolution, we learned that we could discover the reality of our lives and our world through observation, experimentation, and deduction. This began a dance between science and technology that continues to the present. As science progresses, it deepens our understanding of nature and also allows us to build more powerful machines, including new scientific instruments that permit us to dig deeper into nature’s seemingly endless mysteries.

  This tango quickened with the Industrial Revolution, and again with the postwar Great Acceleration. Now we have instruments Galileo could never have dreamed of. We’ve split the atom and built supercolliders to pull apart the subsubatomic particles. We’ve deciphered the chemical assembly lines of living cells. We’ve constructed global networks of sensors that continually measure the composition of our atmosphere, monitor ocean currents, and eavesdrop on seismic vibrations that whisper to us of hidden motions and structures deep within the Earth. To analyze this flood of data, we have microprocessors that double in speed every two years and solid-state memories increasing in capacity even faster than we can fill them with information. Ever speedier computers give us a new way to interrogate the universe, by simulating everything. In addition to the classic twosome of experiment and theory, simulation has become a powerful third form of scientific inquiry. Up in orbit we have massive and elaborate descendants of Galileo’s original telescope peering outward to the edges and beginnings of the universe, and dozens of telescopes ringing Earth, looking back downward. Yes, we’re spying on our neighbors, but we’re also revealing our planet to ourselves as never before. And what do we see? Ourselves—a world transformed by a powerful force that marks it, as far as we know, unlike any other in the cosmos.

  When we first traveled far enough to look back upon our home and see it whole, as in the Earthrise portrait taken by Apollo 8 astronauts, we were simply struck by the beauty and liveliness of Earth in vibrant contrast to the lifeless Moon. Yet now that we’ve been able to observe our planet for half a century with ever-increasing detail, we’ve also started to notice that it is changing.

  Look again at Earth from space. On the scale of worlds, are we really still so inconsequential? Individually, yes, but collectively we are moving mountains, altering rivers, draining seas and filling new ones, and lighting up the dark. Large swaths of tropical forest are disappearing. Coastal waters are choked with nitrogenous sediments, the signs of frantic, unsustainable agricultural activity. Space-based measurements show increasing carbon dioxide and decreased ozone in our atmosphere. The Arctic ice is visibly shrinking.

  We used to say that national borders were not visible from orbit. This was one of the observations made by early astronauts in describing their feelings of unity and transcendence brought on by the orbital overview. These feelings and insights are real, but, sadly perhaps, it is no longer true that political borders are invisible from space. Differing patterns and styles of development have now inscribed some of our abstract political borders into clear, literal lines. One very stark example is the border between North and South on the Korean Peninsula, as photographed from the International Space Station in 2014. [See here of the photo insert.]

  We have to believe our machine-enabled eyes. When we fix our distant gaze carefully and steadily on Earth, we see it morphing under our own influence. The same technological revolution that has afforded us this vastly expanded view has also unleashed these accelerating changes.

  The great demotions were a triumph of humility. Yet we’re awfully proud of them. Our intellectual conquest has perhaps made us a little cocky. In liberating us from the ancient texts and constructing a beautiful new one, illustrated with undeniable wonders from spacecraft, telescopes, and electron microscopes, science has gained a sense of superiority over older, prescientific worldviews. Yet in shooting down traditional worldviews,
science sometimes tends to pump up the human intellect, and our abilities and accomplishments, to godlike proportions. As Carl Sagan writes in Cosmos:

  Once we overcome our fear of being tiny, we find ourselves on the threshold of a vast and awesome Universe that utterly dwarfs—in time, in space, and in potential—the tidy anthropocentric proscenium of our ancestors… We are right to rejoice in our accomplishments, to be proud that our species has been able to see so far, and to judge our merit in part by the very science that has so deflated our pretensions.

  Paradoxically, science today is a strange mix of humility and arrogance. Nobody seeing and thinking clearly would reject its liberating, empowering insights. It’s unbelievable what we’ve discovered. I’m biased, but it gets my vote for most impressive human accomplishment ever. Still, it’s not enough. We wouldn’t be having this conversation if science were solving all our problems. In tossing out other worldviews in our zeal for this one, did we throw out any babies with all that bathwater? Can we find valuable insights and intuitions on how to live well in, and with, this world from some of the prescientific cultures whose world was largely vanquished by the relentless steamrolling advance of our science-driven culture? Many indigenous peoples identified so closely with the natural systems within which they lived that they did not perceive themselves as separate from them. In some ways, we are rediscovering this ancient wisdom. In the words of Chief Joseph of the Nez Perce, “the Earth and myself are of one mind.”

  Many prescientific indigenous peoples intuited that our world is, in some deep sense, alive. When we gained the ability to see Earth from the outside, we could see that they were right. Those first views of Earth as a whole, seemingly living thing lost in the inanimate immensity of space also planted the seeds of a new scientific worldview in which life is not so peripheral. It’s clear when we view our breathing Earth from afar that life is central to the nature of our planet. So, while it’s true that, in the existence of the planet, our species has been here for only a shrug and our civilization only a wink, if we change our perspective and identify with the biosphere, with Gaia, then we’re more than an afterthought, not so ephemeral after all. One way to look at the Anthropocene, at the coming of human influence, the “Phenomenon of Man,” is as a new stage in the long life of the biosphere, one in which Gaia, experiencing the first flickering of self-awareness, is starting to wake up and look around.

  The great demotions were a profound achievement, and provided an accurate narrative of cosmic evolution, up until recently, until the Anthropocene. Now, however, the rules have changed and Earth has entered not just a new chapter, but a new kind of chapter in which we’ve inadvertently made ourselves central. Science now has to recognize the Anthropocene, the geological force of humanity, because otherwise Earth is becoming unrecognizable. We’re no longer just along for the ride. We’re back at the center of the story. This really messes with our heads.

  Is It Official?

  From a cosmic perspective there is no doubt we are in a new stage. Any fool alien watching our planet over the eons could see that Earth is going through a series of novel and dramatic changes. Yet are we officially in the Anthropocene?

  Much popular coverage of the Anthropocene concept has been given over to a protracted academic debate over whether it should be granted status as a bona fide geological time period, and when exactly it started. Both will be ruled on by the International Commission on Stratigraphy (ICS). Stratigraphy is the study and naming of layers of rock and the science of geological timekeeping. It gives us a common temporal road map as we investigate and reconstruct the story of Earth. It’s how we “synchronize watches” at different locations all around the planet and order the simultaneously unfolding subplots of Earth’s complexity into one overall story.

  The ICS is the official keeper of geologic time as represented by the geologic timescale, the series of layers of recognizable rock types, and their associated ages, that unite our global studies of Earth history. The geologic timescale, cobbled together over centuries by geologists all around the world, is a wonderful and precious creation, arguably one of our greatest intellectual achievements. It is not only an indispensable scientific tool, but also a marvelous social and historical construct available to the whole human race (and anyone else who wants to have at it), with which we collectively assemble our story. Armed with the stratigraphic maps drawn and refined by generations of geologists, a hike down the Grand Canyon is not just a steep, rocky descent of six thousand feet, but also an illuminated, annotated journey back nearly two billion years in the life of our planet. Or if you’re hiking in Canyon de Chelly, in the Arizona part of the Navajo Nation, and you come across some fossils in a layer of reddish sandstone that your geologic map tells you is from the late Permian period, then you know they were deposited around two hundred sixty million years ago, at roughly the same time as those other fossils you read about that someone you never met dug up and recorded in northwest Namibia fourteen years ago. These global correlations allow us to put all our disparate knowledge of Earth’s past in a common framework.

  Just the fact that we now have a geologic timescale to maintain, update, and fuss over should serve as, if it were needed, sufficient proof that we are indeed in a unique time of Earth history. At no previous epoch could such a creation, such a tool, exist. That there is a species exploring, excavating, digging up, and piecing together a unified global understanding of our planet’s history—this is itself a creation of uniquely Anthropocene activities.

  You’ve seen this diagram before, or something like it: an idealized stratigraphic column showing the entire geologic timescale. [See here of the photo insert.] It’s a condensed graphical history of our planet, with time running from the origin of Earth, at the bottom, to the present day, at the top. From left to right we see time broken up into successively smaller units, called eons, eras, periods, and epochs.

  Currently the youngest rocks, those at the very top of the column, including those of zero age (those being made right this second, for example, by active volcanoes), are classified as part of the Holocene, an epoch that began 11,700 years ago, at the end of the Pleistocene, when the last ice age gave way to the current warm interglacial. In 2009, an “Anthropocene Working Group” was convened by Jan Zalasiewicz of the University of Leicester, to study establishing the Anthropocene as a formal part of the geologic timescale, an epoch that would follow the Holocene, marking the time of human influence. Their proposal will be put forward to the ICS to become recognized internationally. After that, it will surely be subjected to multiple rounds of revision, and it remains to be seen if the Anthropocene will ever be formally adopted as an epoch with an agreed-upon start date. The process is inherently conservative, which it ought to be. You don’t want to casually mess with the geologic timescale.

  In 2011, a cover story in The Economist declared, “Welcome to the Anthropocene.” The term has gone mainstream, and the fact that the human presence on Earth has drastically altered many (previously) natural systems is no longer controversial. Yet does this qualify our time to be a new, formally named geological epoch? Some geologists regard this as more of a stunt than a serious matter of stratigraphy. They worry that it is designed to help marshal concern over environmental issues, and is thus motivated more by politics than science. Some scientists expressed alarm when they saw the term being adopted by the mass media to describe a geological concept that the geological community had not itself formally adopted. A 2012 Geological Society of America article by two stratigraphers asked, “Is the Anthropocene an Issue of Stratigraphy or Pop Culture?”

  In part, they argued that our presence is as yet too brief a perturbation to merit a named place in the stratigraphic column. The amount of ocean sediments laid down since World War II is less than a millimeter. And, of course, nobody knows how long the Anthropocene will last. That depends crucially on how we, collectively, respond to the novel realization that we’re now in such a time. Our presence, however, is already i
ndelibly inscribed in Earth’s stratigraphic history, and as long as (or whenever) there are geologists, it will be identifiable.

  Whether or not it becomes “official,” the term Anthropocene has struck a chord, and it helps frame our current and future challenges in deep time, in geological time, in Earth time. The stratigraphers gave us an enormous gift in starting these contemporary discussions of the concept, but they don’t own it anymore. If the Anthropocene started out as a question of stratigraphy, it has long escaped that domain. It is now being debated by scientists from a wide range of fields—not just earth science but also biology, anthropology, archaeology, ecology, and even astrobiology. The discussion has also spread far beyond the halls of science to include historians, philosophers, ethicists, literary scholars, artists, and poets. If the stratigraphers conclude their debate and decide that no, sorry, there really is no Anthropocene epoch, I doubt anyone will take too much notice. The wide informal usage of the term has already outstripped the pace of the debate over its status.

  When Did It Start?

  The biggest kerfuffle has been over when, precisely, this new era began. Was it in the late eighteenth century, at the beginning of the Industrial Revolution, when James Watt’s steam engine first began revving up the wheels of industry and began adding excess CO2 to the atmosphere?1 Or was it thousands of years ago when, through the spread of agriculture, we first began systematically modifying the landscapes of our planet, burning and cutting down forests and replacing them with cultivated fields?