Breathing is so universal and continuous that it can be easy to forget about—until we can’t do it anymore. Then it becomes symbolic of life itself. We take special note of words that are carried on final breaths, and sometimes we even cherish the physical substance of the breaths themselves. Henry Ford kept a glass test tube of air in his home for many years, and inside the tube was said to be a sample from the last breath of his late friend and fellow inventor Thomas Edison. According to sources at the Henry Ford Museum in Dearborn, Michigan, several such tubes are believed to have been left open to the air of the room near Edison’s deathbed. “Though he is mainly remembered for his work in electrical fields,” Edison’s son Charles reportedly said, “his real love was chemistry. It is not strange, but symbolic, that those test tubes were close to him at the end.” After Edison’s death, Charles had the tubes sealed and later passed one of them on to Ford as a memento.
Keep this in mind as you take your next breath. Notice how you tighten your diaphragm and relax the muscles in the walls of your chest. This effort alone consumes roughly 3 percent of your metabolic energy at rest, all in order to pull the equivalent volume of a grapefruit into your lungs. Trillions of air molecules are now trapped within your chest like fish in a net. Only a few of them, the oxygens, are what you’re after. An average adult uses nearly two pounds of them every day, and this particular breath full will help to keep you alive for the next few minutes. It will also connect you to the rest of life on Earth and to the planet itself in surprising ways that we will soon explore.
Depending on the time of day and the season of the year, the air you walk through and pull into your lungs changes more than you might expect. This is just one of many discoveries by Ralph Keeling, a scientist at the Scripps Institution of Oceanography who tests the atmosphere the way a police officer might test your breath with a Breathalyzer.
For more than two decades Keeling has been measuring the oxygen content of air samples that are collected daily in Hawaii, Antarctica, and elsewhere, sealed into small containers, and shipped to his lab in La Jolla, California. Like traces of alcohol in someone’s breath, slight changes in the composition of the atmosphere can tell a lot about what the world’s combined masses of people, vegetation, and plankton are doing.
It is often said that forests are the “lungs of the planet” because they produce oxygen that we breathe, but the metaphor falls short in some respects. Lungs don’t produce oxygen but instead consume it, and Keeling’s work has shown that only about half of your oxygen comes from terrestrial plants. The rest is made by algae and cyanobacteria in lakes and oceans, with a small additional measure produced by the splitting of water vapor in the upper atmosphere by radiation from the sun and distant stars.
However, when combined with the carbon dioxide analyses that his late father, Charles David Keeling, launched at Mauna Loa Observatory in Hawaii in 1958, the long-term oxygen records do show an almost eerie resemblance to the readouts of a medical breath-monitoring device. Annual pulses of oxygen are mirrored by cyclic drops in CO2, and together these data open a unique window on the atomic connections between plants and the earth.
When the elder Keeling first began to study the air, he expected it to vary a great deal from place to place. To his surprise, however, much of the variability vanished when samples were collected with consistent methods at remote locations where the air is free of local influences from respiring forests and cities. The atmosphere mixes more thoroughly and rapidly than scientists had hitherto realized, and average CO2 concentrations in Hawaii are remarkably similar to those at the Scripps pier in La Jolla.
Equally noteworthy, however, were various kinds of rhythmic oscillations that appeared in the gas records. Every day the carbon dioxide concentrations dropped slightly, only to recover at night, and larger seasonal pulses occurred with dips in summer and peaks in winter. When Ralph Keeling began to measure oxygen to complement his father’s work, his results showed similar patterns but in reverse. With these data you can watch the atmosphere respond to the breathing of countless plants and microbes as the earth spins on its axis and circles the sun.
The pacemaker of these pulses is sunlight. When dawn awakens California, the lawns and palm trees of La Jolla begin to pump oxygen into the air and pull carbon dioxide out of it, as does the Pacific plankton drifting offshore. When that portion of the world spins onward into the shadow of night again, the oxygen production shuts down, but the cellular CO2 factories keep running and quickly drive local carbon dioxide levels back up again while oxygen levels drop.
A similar pattern emerges in alternating hemispheres through the seasons, as well. When plants sprout and leaf out in spring, O2 rises rapidly and CO2 declines. Later in the year when photosynthesis slows and dead leaves begin to decay and release carbon dioxide, the opposite trends prevail.
The Keeling records clearly show that we affect the atmosphere, too, but in more disturbing ways. In early 2013 average concentrations of heat-trapping carbon dioxide reached 400 parts per million (ppm, or a ten-thousandth of a percent), having risen from an average closer to 312 ppm during the 1950s. Most of that change represents the burning of fossil fuels along with the decay and fires associated with deforestation. Unlike the photosynthesizers, these artificial “lungs” of the modern world consume O2 and release CO2 like our own, and they do it continuously on a massive scale.
While the long-term carbon dioxide record tilts upward along with global average temperatures, the oxygen trend points downward. According to the Scripps O2 Program site, oxygen concentrations at La Jolla dropped by 0.03 percent between 1992 and 2009. This, as Ralph Keeling said in an interview with the San Diego Union-Tribune, is the global “signature of combustion.”
Should we now worry about running out of oxygen in addition to global warming? Not according to Keeling. In another Union-Tribune interview he explained that there is plenty of oxygen in the air, and the tiny percentage of loss of oxygen in itself isn’t an issue. Rather, “the trend in oxygen helps us to understand ... what’s controlling the rise in CO2.” In other words, declining oxygen shows how closely tied we are to this planet, and how much we now affect the atomic world around us.
From space, Earth resembles a floating blue bead, and if you keep that image in mind it will help to drive home an important lesson. As abundant as atoms are on this planet, their numbers are finite. Watch a satellite video of the clouds that sweep across the face of the world, and you will see in an instant that the winds that carry them over one curved horizon may reappear on the opposite horizon. When viewed from a great distance the sky resembles a shockingly thin film, and most of its molecules are packed into a mere 10-mile slice of a total planetary diameter of nearly 8,000 miles. At sea level you might find more than 10 trillion trillion atoms in a cubic yard of air, but just outside that vaporous skin is the relative vacuum of the solar system. The next time you see a photo of the earth taken from space, try to convince yourself that a pollutant-spewing smokestack anywhere in the world doesn’t unleash potentially harmful substances into the same precious air supply that keeps you and your loved ones alive.
Keeling showed that oxygen gas emitted by plants and plankton mixes throughout each respective hemisphere within two months and spreads worldwide in a little more than a year. The sensitivity of the oxygen and carbon dioxide balance of the atmosphere to the activities of living things shows that recycling is not just a passing fad but a tradition that has always been practiced on the atomic level by all life on Earth. To live, rather than to merely exist like inanimate rock, is to borrow and repurpose the elements of the world around you, and then release them again.
As brilliant as he was, Henry Ford apparently failed to realize that he needed no test tube to capture the atomic essence of Edison’s last breath. You can collect a sample of it anytime—along with samples from the last breaths of Jesus, Shakespeare, and Leonardo—and even with a few bits of air that carried your own first cries as a newborn. It’s easy to do, here on this sky-blue sphere of atoms. Just take a breath.
Excerpted and adapted from Your Atomic Self* by Curt Stager. Copyright © 2014 by the author and reprinted by permission of Thomas Dunne Books, an imprint of St. Martin’s Press, LLC.*
Editor: Samantha Oltman (@samoltman)
