Home, Sweet Earth
When the doors close on a commercial airline flight, the tension begins. How soon until they open again? With the possible exception of any youngsters still enamored with the adventure of air travel, most passengers have high hopes for a quick takeoff, smooth trip and safe arrival. While some may fret over the possibility of a long wait on the tarmac or the loss of their luggage, few stop to consider the environment they will soon be entering. At 30,000 feet there is too little oxygen outside to sustain human life; the temperature on the other side of the Plexiglas window is dozens of degrees below freezing. It is a profoundly harsh and deadly environment through which the relatively small habitable tube will be traveling.
Understanding that the Earth itself is merely a larger version of that aircraft is even more eerily discomforting. If something goes wrong here, there is no other place to go, no safe harbor to seek. Coining the phrase “Spaceship Earth,” 20th-century visionary Buckminster Fuller once noted our nonchalant relationship with our safe world: “Spaceship Earth was so extraordinarily well invented and designed that to our knowledge humans have been on board it for two million years not even knowing that they were on board a ship.”
Our planet not only carries us through the void of space, but at the same time provides for all of our life-support needs without, it seems, even trying. But to be captured in the naive assumption of perpetual comfort was to Fuller a dangerous idea. “We have not been seeing our Spaceship Earth as an integrally-designed machine which to be persistently successful must be comprehended and serviced in total.”
As a designer and originator of the geodesic dome, Fuller understood the concept of the “design envelope”: the understanding that all things, even planets, must operate within certain tolerances. To stretch the envelope or push a system beyond those limits is courting disaster. The potential for eventual collapse of the entire system as a whole is possible when critical parts begin to fail under loads exceeding their capacities. This is not an unfamiliar concept to the engineer. Unfortunately, it is also a concept that is becoming all too familiar to the ecologist.
Is such a cascade of ecological failures possible on a planetary scale?
Knowing the Place
When Fuller wrote his Operating Manual for Spaceship Earth in the late 1960s as a call for a different way of thinking about the earth’s resources, human beings had not yet traveled beyond Earth’s orbit. Three astronauts aboard Apollo 8 would be the first to see the Earth from a distance in December 1968. Their famous “Earthrise” photographs from across the horizon of the Moon finally revealed the stark reality of humankind’s isolation on the small blue sphere hanging in the blackness of space.
These images were the first fruits of the space age which had begun a decade earlier amid an explosion of discovery on earth. For 18 months spanning 1957 to 1958 scientists and engineers across the globe participated in a concerted effort to better understand our planet. Referred to as the International Geophysical Year (IGY), the project’s mission was to coordinate more than 60,000 scientists in a massive experiment “in concert.” It would be an examination of the Earth from Arctic to Antarctic, upper atmosphere to ocean depths. According to journalist Walter Sullivan in his 1961 report, Assault on the Unknown, the chief organizer of the American efforts called the venture “the single most significant peaceful activity of mankind since the Renaissance and the Copernican Revolution.”
Following in the footsteps of smaller-scale efforts in 1882 and 1932, the physical scientists made great strides in understanding the Earth’s structure holistically. Their findings provided the first intimations of the great geochemical cycles beneath our feet and the fine details of the seemingly vacuous void above our heads. It was as if the doctor was discovering the heart that drives the pulse.
Not only was the space age born with the Russian Sputnik and the American Explorer and Vanguard launches, but also during this time oceanographers focused on the sea floor and its great trenches and rifts, while geologists tapped out a seismic analysis of mountain ranges. Today those preliminary sketches have become a full-color picture of plate tectonics.
Earth Systems
In the succeeding 50 years we have gained further insights into the unique qualities of the Earth that make life possible here and, as far as we know, nowhere else. Our knowledge base has expanded not only from further Earth-based investigation but through 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 Saturn’s largest moon Titan. We have witnessed the impact of asteroids on Jupiter and collected Martian meteorites in Antarctica. Meanwhile, our telescope-aided eyes continually scan the deep heavens searching for other Earth-like worlds, so far to no avail.
Earth’s special status is often attributed to the fact that its distance from the Sun falls within the “habitable zone” demarcated by its size and luminosity. But while Venus and Mars are also within this zone, they are certainly not habitable today. There must be more to the Earth’s success story than simply, as a cosmic realtor might say, “location, location, location.”
The difference is not just the energy we receive from the Sun but also how that energy is reflected and absorbed by our atmosphere. The energy-storing property of water is obviously important to our heat balance as well. But without a layer of air and the pressure it creates (which is a function of gravity that operates in accord with the planet’s overall size—another key factor in the overall Earth system), water would evaporate and dissipate into space.
Commenting on her first view of the Earth from space in 1983, Sally Ride said, “I remember the first time that I looked towards the horizon it looked as if someone had taken a royal blue crayon and just traced along the Earth’s horizon. And I realized the really thin royal blue line was Earth’s atmosphere, and that was all there was of it. And it’s so clear from that perspective how fragile our existence is.”
Ride’s remark underscores the critical importance of the atmosphere as far more than something to breathe. It is our shady umbrella during the day and our comfy blanket during the night. Without it Earth would be like the moon: dry, still, and either extremely hot or extremely cold. The concentration and combination of its various gases is also critical. A greenhouse effect is a good thing, but one does not want too much of a good thing.
This is Venus’ problem; she is simply too hot. This is not the result of being too close to the Sun; but rather of having the wrong atmosphere. Although Venus is similar in size to the Earth and therefore has similar gravity, its atmosphere of 96 percent carbon dioxide traps the heat and creates a much higher surface pressure than our meager 16 pounds per square inch (psi) or 1,013 millibars. While we are accustomed to having the weight of a bowling ball pressing down on each square inch of our bodies, the Venutian pressures and temperatures, 1,450 psi and almost 900 degrees Fahrenheit respectively, have quickly incapacitated even the Russian’s hardiest unmanned landers.
Our planet’s mean temperature of 59 degrees Fahrenheit provides for water existing in all three phases, solid, liquid and gas. So while Venus is certainly too hot for any kind of a water cycle, Mars, on the other hand, is too cold. It is clear that Mars once had flowing water on its surface and thus the possibility of life, but its water is now locked up as ice. The reasoning behind NASA’s current “Follow the Water” mission plan for exploring Mars is based on the assumption that liquid water is a proxy for life: the very thing that makes the Earth unique.
Home Sweet Home
The Earth is a habitable place, a place that allows a very small physical window within which the biochemistry of metabolism, reproduction and adaptation can operate. Our neighbor Mars may have had such an open window once, but our robotic explorations of its surface reveal that it was shut long ago. Its dry, cold landscapes appear analogous to our arctic tundra in some ways, but not in ways that really matter. There are no lemmings, or mosses, or even microbes on the Martian plains.
But Earth’s uniqueness stretches even beyond the biochemistry of cells to human life and human consciousness. Something very unusual has happened here on Earth. Not only is there life—a still unmeasured and probably forever incalculable cornucopia of living creatures from bacteria to 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.
Through our clever abilities to manipulate the environment, our population has grown to dominate the planet in number and influence. While some may cheer and others lament this fact, our species has become the global player. Considering this reality, chemist and Nobel Laureate, Paul Crutzen, writes 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.” This realization has led to some interesting characterizations.
Some call us a cancer on the planetary body, eating away at the resources and systems that sustain all life. Others refer to our impact as that of an asteroid, convulsive and shattering, an extinction-generating event.
Incomprehensibly, many of a religious persuasion believe we are admirably following the Creator’s instruction to “be fruitful and multiply and fill the earth and subdue it and have dominion” (Genesis 1:28 English Standard Version).
The consequences of misinterpreting these marching orders have been profound. While the context indicates that to be fruitful simply means to have children, like the parents, made in the image of God, it begs the question of what that image might be. Is this merely about physical form or does it extend to the responsibilities and obligations that are part and parcel of having a creative mind?
The other actions, multiply, fill, subdue and have dominion are even more problematic. To many, these convey that human beings have carte blanche to utilize the Earth as we will; to basically “take over” our environment. Large and in charge, are we then free to exploit the planet’s resources while amassing the largest human population possible? A few decades ago such a question would have been pure fiction. When life spans were short and child mortality was high, to have dominance over nature seemed impossible.
Before this century we would not have imagined a world of multiple billions. Neither would we have imagined the age of industry, medicine, commerce, agriculture, sanitation and affluence that support those numbers. Billions may exist in the depths of poverty, but the ecological pressures the minority exert and the remainder seek to exert are also growing exponentially. As our numbers have increased and the stresses we place on planetary systems have apparently become more malignant, the concept of “stewardship” must be blended into the equation. In other words, can we be caringly dominant over the earth if we can’t subdue and have dominion over ourselves?
“Think of it,” said R. Buckminster Fuller in 1980, “We are blessed with technology that would be indescribable to our forefathers. We have the wherewithal, the know-it-all to feed everybody, clothe everybody, and give every human on Earth a chance. 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.”
If we really do have such power, it is certainly time to harness it for the good of Spaceship Earth. For no matter where or how we look for an alternate planet on which to live, there really appears to be no place like home.