Something very unusual has happened here on Earth. Not only is there life—a still unmeasured and probably forever incalculable cornucopia of life from bacteria and algae to sequoias and whales—there is also life that knows it’s alive. This one planet is home to a conscious being with the audacity to call itself wise: Homo sapiens. Yes, if we can think of it, then we can eventually do it. Sometimes, though, we find we must follow “We can do this” with a worried “What have we done?”
In our wisdom we have dreamed and created, built and innovated using our willful mind rather than animal instinct, and this has made us a kind of geologic force. This phenomenon has now, unfortunately, brought us into apparent collision with the planet itself. We are able now to tamper with the dials of Spaceship Earth (as 20th-century visionary Buckminster Fuller called it) to such a degree that we are threatening our own livelihood. Some end-time scenarios reflect the worst outcome of human invention: nuclear or biological warfare leading to biological annihilation. But such a disaster would be a premeditated horror rather than a mistake of technology. We are learning that there are other roads to speciecide; even apparently benign technological innovations are often interlaced with unintended consequences.
While there is growing agreement that there are many ways to upset the apple cart of civilization—climate change, water scarcity, energy crisis, habitat destruction, species extinction—some scientists are intrigued with the ever-increasing possibility of discovering ways to again twiddle the dials and restore planetary homeostasis.
“We know now what we could never have known before—that we now have the option for all humanity to ‘make it’ successfully on this planet in this lifetime. Whether it is to be Utopia or Oblivion will be a touch-and-go relay race right up to the final moment.”
Will we through so-called geoengineering cobble together the technology to help us avert disaster? Alan Robock, associate director of the Center for Environmental Prediction at Rutgers University, says the problem of global warming, for example, is geopolitical rather than geotechnical. We need to rethink our actions, not invent new ways to engineer the planet itself. “Scientists may never have enough confidence that their theories will predict how well geoengineering systems can work. With so much at stake, there is reason to worry about what we don’t know.” Robock concludes, “If global warming is a political problem more than it is a technical problem, it follows that we don’t need geoengineering to solve it.”
Meanwhile as governments remain stymied when it comes to consensus on what to do about the many activities that continue to threaten civilization’s sustainability and the biological health of the planet, still other scientists look not for a new Earth down here but a new Earth up there. Literally rising above the downside of our technology, more outward-focused tools of science have enhanced our ability to scan our planetary neighbors and other solar systems for evidence of life. Frank Drake, professor emeritus of astronomy and astrophysics at the University of California–Santa Cruz, predicted nearly 50 years ago that we would soon discover multiple Earths and a universe full of ideas useful in solving our terrestrial difficulties.
“I claim,” he wrote in Is Anyone Out There? The Scientific Search for Extraterrestrial Intelligence, “. . . that there are approximately ten thousand advanced extraterrestrial civilizations in our Milky Way Galaxy alone. I believe that what they have to tell us is of supreme importance.” Although Drake’s SETI (Search for Extraterrestrial Intelligence) program has so far bored only dry celestial wells, the potential for contact from above remains mathematically possible. Might such a positive find help us bridge the void in our nature that prevents us from making our Garden-of-Eden dreams reality? Or, on a less savory note, might finding life elsewhere lead us to the tragic conclusion that life on Earth is not really all that precious after all?
Worlds in Collision
Humans have always been skeptical of their potential to impact the environment. When we collided with it—for instance, when pushing nature away to plant a crop, or when combating a large predator—we were at its mercy; nature always bounced right back. Succession returned whatever we wiped away. For millennia the environment has been our enemy, the opponent from which we extracted our sustenance through continuous toil and sweat. While this remains true for a great many of us—the billions who live in constant thirst and hunger continue to suffer both the vagaries of nature and the fickle hand of fellow man—the level of comfort that the minority enjoy certainly seems a completely separate sphere, a kind of off-planet world that one sometimes sees in a science fiction movie. So when the ancient author of Genesis wrote that humankind would have planetary dominion, many observers must have been amused. How would fragile man ever subdue nature?
Modern doubters continue to echo this sentiment, but a quick mental scan of the natural world shows that it is only the menace of microbes and our own intramural conflicts that we have not conquered. All other life continues to thrive or collapse at our hand. The wonder of Google Earth has made it possible for anyone with an Internet connection to see that our man-made world pushes ever harder against the natural world.
This is not to say, as popular media programs point out, that if humankind were suddenly to disappear, natural forces would not eventually consume and reduce to dust all that we have put in place; it is certainly true that without constant maintenance on our part, all evidence of man would erode away given enough time. Nevertheless, from seafloor to upper atmosphere, the entire planet has been touched by human activity. We need look no farther than our own bodies to validate this reality in microcosm: we all carry within us the isotopic signature of human-caused planet alteration. Nuclear residue from above-ground atomic testing in the 1950s and ’60s as well as the Chernobyl accident of the late ’80s is embedded in all but the youngest of us. If that is not weird enough, consider our diet for another source of atomic shift. Corn plants have a preference for one type of carbon isotope over others during photosynthesis. Our corn-dominated food chain has created an atomic signal within us as well. We ironically no longer need to wait on the beach for the wind to bring us an atomic influx from afar; we self-administer it from the grocery store.
Are these bad things? Do such alterations matter? The answer is uncertain and the possible push-backs one hears depend mainly on the person to whom one poses the questions. These are merely the less obvious examples of our global fingerprint. To some they reflect an incredible accomplishment, a sign of intelligence, if not wisdom; to others they are evidence of our cavalier hubris. Either way it points up the necessity of becoming more aware of our integrated place in the global system. Whether one believes that the Genesis statement was a prophecy, a promise or a prank, it has apparently come to pass. Still, there is more to having dominion than simply taking over.
Insects and human beings are the dominant macroorganisms on Earth today. Sociobiologist and enthusiastic ant specialist E.O. Wilson has calculated that the mass of ants and people on Earth are approximately equal—a “back-of-the-envelope” calculation, he says. Noting the intricate roles that these little creatures, along with all of the insects in total, play in biosphere services, the Harvard entomologist believes they are the minute gears that keep life-sustaining processes turning. He calls them “the little things that run the world.” On the other hand, according to Wilson, humans are the big things that seem to get in the way of the world working. “We’ve got to settle humanity down,” he says, “before it wrecks the planet.”
But settle it down to what? Must we back up to go forward, or do we merely need a better idea of what forward means? (See our interview with Paul Ehrlich.) What we have built so far is a kind of supernature, a world within a world built atop nature itself.
Our growing understanding of the complex systems of planet function reveals, however, that this is not a lasting situation. We have deluded ourselves with a false sense of planetary independence. Rather than insects (even the annoying or dangerous ones), which are integral parts of the biosphere’s regulatory structure, we are more akin to planetary parasites; we derive everything that sustains us from the around and contribute nothing in return. We are the only creature that has no ecological value-added component. This may be a somewhat harsh and puzzling assessment, but it should challenge us to take a closer look at why we are here at all. Do we have a role to play? Are we nature’s biggest mistake, another temporary evolutionary dropping-of-the-ball like trilobites or dinosaurs? Or are we God’s greatest creation that has somehow lost its way?
“The universe was made on purpose. . . . In the fabric of space and in the nature of matter, as in a great work of art, there is, written small, the artist’s signature. Standing over humans, gods, and demons, . . . there is an intelligence that antedates the universe.”
Again, we are the unusual thinking creatures that ask such questions. But like other physical beings, we, too, are totally embedded in the ecologic services of the biosphere. Overuse of the term tipping point has diluted the reality that all systems exist in a balance of interconnectedness. Can we so disrupt the natural systems that they can no longer support our growing numbers?
The human population has more than tripled in the past 80 years from 2 billion in 1928 to almost 7 billion today. That is an amazing number; picture it as more than 2 million people per word in this article. It is no surprise that to octogenarians the world seems a more crowded and hectic place. It is not just the fact that news travels faster; there really is more news about more people doing more things in bigger ways than ever before. Considering this reality, chemist Paul Crutzen writes that we must agree that “to develop a world-wide accepted strategy leading to sustainability of ecosystems against human induced stresses will be one of the great future tasks of mankind.”
Informally in 2000, and then formally in 2002 in a brief article in Nature, Crutzen coined the term Anthropocene as descriptive of our impact on the world at large. A new epoch in earth history, he suggested, had begun; the post–ice age Holocene epoch of the last 10,000 years had given way to us and our biosphere-altering habits. From this viewpoint he first pitched the concept of geoengineering as a means of ameliorating the unintended consequences of our shifting the carbon dioxide content of the atmosphere. If we caused the problem, maybe we could fix it.
Tapped decades ago as a possible means of restoring habitability to Mars, geoengineering simply means to modify nature to human ends. For Mars, it was suggested that we find a way to thicken its atmosphere to create a stronger greenhouse effect; Mars is too cold to sustain liquid water, a necessity for life. On Earth, geoengineering includes designing and constructing dams, levees, breakwaters and any large structure that alters nature’s course in a purposeful way. Adding carbon dioxide through combustion was not intended to have a global effect; if that indeed has been the effect, then to retrofit the atmosphere to compensate for it is a bold challenge. But again, if we can think it, we can do it. Is this, then, the way forward?
“The realisation that existing efforts to mitigate the effects of human-induced climate change are proving wholly ineffectual has fuelled a resurgence of interest in geo-engineering,” says Tim Lenton of the University of East Anglia’s School of Environmental Sciences. His paper, “The Radiative Forcing Potential of Different Climate Geo-engineering Options,” examines the various proposed means of stabilizing climate change. These include nutrient fertilization of the oceans, cloud seeding, sunshades in space, stratospheric aerosol injections, and ocean pipes (for injecting water vapor above the oceans). “Stratospheric aerosol injections and sunshades in space have by far the greatest potential to cool the climate by 2050,” Lenton says, then cautiously concludes, “but also carry the greatest risk.”
Crutzen’s initial suggestion of such a plan is surprising given his atmospheric expertise. He received the 1995 Nobel Prize in chemistry for his work concerning stratospheric ozone and the impact of chlorofluorocarbons (CFCs) on its stability. CFCs had been used as refrigerants for 50 years but, based on the work of Crutzen and others showing their ozone-depleting capacity, were phased out after a worldwide ban in 1990.
“There is no adult who cannot actively affect what happens in his or her personal life if he or she chooses to do so. But now the choices are far more complex than simply deciding not to have a large family.”
The ozone layer and the chemical interactions within the upper atmosphere, or “ignorosphere” as Crutzen called it in his Nobel lecture, are another underappreciated detail in the workings of the planet. To be able to affect its structure, realize the effect, and alter our chemical industry before irreversible damage had been done, was a fortunate break. Crutzen remarks, “Noting that nobody had given any thought to the atmospheric consequences of the release of Cl [Chlorine] or Br [Bromine, an even more ozone-unfriendly element] before 1974, I can only conclude that mankind has been extremely lucky.”
The 2006 demotion of Pluto—it’s now a “plutoid”—reduced our solar system’s planet count from nine to eight. While many rallied to Pluto’s defense, there was no need to worry that somehow we had become a little lonelier. Telescopic surveys peering out beyond our solar system have identified more than 300 other planets; the list is being continually extended. Our Milky Way galaxy is composed of billions of stars and likely contains multiple billions of planets. And there are billions of other Milky Ways. As the Drake Equation speculates, there seem to be many “spare” planets. Could we, as promised in the movies, just move to another if we break this one? How lucky would that be!
While the possible numbers of planets out there are uncountable, the question of habitability looms large. Most of the extra-solar planets so far discovered have characteristics more like Jupiter—massive, gaseous—and orbit near to their host star. More sensitive means of detection will soon come into service, making it possible to more easily discover planets similar to Earth in size. The Kepler satellite observatory, launched in 2009, in combination with the refurbished Hubble Space Telescope and various ground-based instruments, promise to reveal many new worlds. But the existence of planets, including Earth-like rocky planets close to sunlike stars, is not enough for life.
Even what astronomers call the habitable zone around a star includes uninhabitable planets, as our solar system shows. Earth, Venus and Mars are all within the habitable zone. But factors other than distance from the sun control a planet’s temperature and therefore habitability. The structure of a planet’s atmosphere is key in controlling surface temperature. If we were warmer, like Venus, all of our water would have boiled away; if colder, like Mars, our water would be locked up as ice as it is there.
It is only under the most unusual circumstances, more through the stumbling along of scientific investigation than through the purposeful upward march of knowledge, that we have become aware of these details. Crutzen’s ignorosphere may be more descriptive than he realized; we tend to ignore most of the around until there is a sudden need to know.
We are embedded in a sort of cosmic and ecological obliviousness, the infinite world of mind and imagination gravitationally anchored to a small rock in a tiny outpost in the vastness of space. When we dream of extraterrestrial life, we often do so with little regard for the intricate fabric of details—the ants, the ozone, the sun, the atoms—that taken together make life on Earth possible. The difficulty in finding extraterrestrial life well illustrates our need to reevaluate our behavior as the dominant species. Coming to terms with the unique features of the Earth that make life possible here, in contrast to everywhere else we have looked, can motivate us to stop ignoring, downplaying, or simply wringing our hands over our impact. Rather, understanding our place in the universe can inspire our willful move toward an ethic of stewardship and cooperation and away from unthinking exploitation and competition that drives consumption for its own sake, as if somehow supporting the greater good.
An Age of Responsibility
In the last 50 years we have gained insights into the unique qualities of the Earth that make life possible here and, to our knowledge, nowhere else. These have come not only from Earth-based investigation but through an exploration of our solar neighborhood as well. We have walked the surface of the moon, our nearest extraterrestrial neighbor, and sent robotic vehicles to Mars and Venus. We have deposited probes into the clouds of Jupiter and of Titan, the largest moon of mysterious Saturn. We have witnessed a comet impact Jupiter and have collected Martian meteorites in Antarctica. Meanwhile, our telescope-aided eyes continually scan the deep heavens searching for other Earth-like worlds. But so far, we (and our coterie of several million other species that inhabit this spaceship) are it.
Our knowledge of the physical planet has given us access to its resources in ways not available to any other species. While a bird may tweak a twig to build a nest, or a spider twist a leaf to the same end, only we have the willful capacity to bend the planet to our desires. In doing so, we have taken charge of not only our destiny but that of our fellow Earthlings as well.Our understanding of the planet and our interaction with it has revealed that we are not simply passengers. We, like all living things, are participants in the systems that maintain life. Our spaceship tends to our needs, ever recycling, recharging and renewing those things life requires. The biosphere is an integrated whole, a synergy of living and nonliving units that is self-sustaining. We easily overlook the fact that every molecule of oxygen we breathe has cycled through a plant or that every ounce of fresh water we drink was once part of the sea. And unless we must rely on bottled water or on a well that we must physically pump ourselves, it all comes to us for little or nothing—so long as we do not break the system.
“To survive, we must close the circle. We must learn how to restore to nature the wealth that we borrow from it.”
For most of our tenure on the planet our impact on this synergy has been small because we have been small. But now humankind has become the ultimate invasive species. Our numbers are increasing and our technological know-how is immense. Will we be able to accept the responsibility that comes with our ability to change the planet? Crutzen concludes, “An exciting, but also difficult and daunting task lies ahead of the global research and engineering community to guide mankind towards global, sustainable, environmental management.”
Doing these things will require new ways of thinking and living that will no longer tolerate putting away the details into a personal or collective ignorosphere. The old Earth that we once believed was immune to our presence is gone, part of the obsolete wisdom of the past. We must choose to act on the realities of the new Earth, a place we have come to understand is finely tuned to sustain us while also responding to us. On this unique planet, our decisions have global consequences for all life that cannot be indefinitely ignored.