Written by contributing author, Peter S. Wenz
One of the most important characteristics of many living things, including all mammals, is the control of their temperature. When we’re hot, we maintain our body temperature by moving from the sun to the shade, perspiring so that evaporation cools us, and reducing our exercise. When we’re cold we exercise, shiver, and put on warm clothing. Other mammals grow hair or increase layers of fat.
Rocks don’t do these things. When the ambient temperature is hot, they’re hot; when it’s cold, they’re cold. The earth is more like a mammal than a rock. Its temperature has stayed relatively constant since life began 3.5 billion years ago, yet it now receives 30% more heat. If earth were just a rock, it would be 30% hotter.
It seems that life on earth is the key. Plants use carbon in photosynthesis, thereby removing CO2 from the atmosphere and replacing it with O2. About 0.1% of the carbon that has been taken out of the air and added to the biomass of plants is buried where it can’t combine again with oxygen to form carbon dioxide. The resulting reduction in atmospheric CO2, a heat-trapping gas, helps to keep the earth’s temperature nearly constant.
Plants and other forms of life seem to be responsible also for the oxygen content of the atmosphere, which was meager before plant growth absorbed carbon from CO2 and released free oxygen. The oxygen content of the atmosphere increased to its present 21%, where it has been for eons. Had the increase continued, life as we know it on land would be impossible. At 25% oxygen concentration, lightning strikes would burn even wet plants, destroying all forests from the tropics to the arctic, and making the evolution of land animals improbable.
Anaerobic bacteria are the primary agents that inhibit the continued increase of oxygen levels. These bacteria live without oxygen in such oxygen-free zones as mud flats, marshes, river estuaries, and sea beds. They produce methane (CH4) which combines with atmospheric oxygen to form carbon dioxide and water. The result is less free oxygen in the atmosphere. Without this process, our atmosphere would contain 25% oxygen in a mere 50,000 years. We don’t (yet) know all the details, but it seems again that life on earth keeps the earth suitable for life.
Similarly, salt concentration in the oceans tends to increase as rain dissolves the salt on land and washes it into the sea. Yet, the salt content of the seas has been steady for a long time, constituting 3.4% of the sea, which is good because few life forms in the ocean can live with a salt concentration above 6%. In this case too, without an alternate hypothesis, we should probably attribute this life-saving effect to life itself.
Several other examples could be given, but the point is clear; life on earth seems to maintain the conditions necessary for its perpetuation. I am awestruck by this mysterious system, and aware that human food consumption could imperil it.
Human impact
Our earliest ancestors were foragers who hunted animals and gathered food like most other animals. They didn’t alter the course of nature in order to bring forth more food for people than the planet would otherwise provide. Later, pastoralists raised animals, mostly for their products, such as milk, as well as for their meat, fur, hides, and bones. This practice increased the populations of some animal species, which altered the consumption of some plant species. But for the most part, the animals were moved from place to place to eat what was available without much human intervention. People didn’t grow food for their herds.
By biblical times, however, although foraging and pastoralism continued to exist, most human food was produced through massive habitat alterations – plowing, irrigating, fertilizing, weeding – to sustain human populations much greater than would otherwise be possible. We 1) hunt our competitors to (at least local) extinction (no wolves should take livestock); 2) destroy competitors’ food to make room for our own (plow up tall grass prairies); and 3) deny competitors access to our food. Agriculture is our greatest imposition on natural systems.
What does reverence require?
Since poorly understood systems of life forms may be essential to the continuation of life on earth as we know it, reverence seems appropriate. One way to show reverence is to reduce one’s own imposition on natural systems through more earth-friendly eating habits. In general, nutrition through meat requires greater disturbance of life systems than nutrition through grains, fruits, and vegetables, because animals raised for meat in industrial countries use most of earth’s bounty for their own maintenance. Only one tenth to one fourth reaches people.
This doesn’t mean that having reverence for nature’s systems requires vegetarianism, much less veganism. We are social animals whose perspectives, practices, and welfare are tied to that of other people. A reasonable goal is just to consume less of the most earth-disturbing foods than others in your society or social group. In fact, beef consumption has fallen in the United States nearly 40% in recent decades. When such positive developments occur, stay ahead of the curve. If most people eat two pounds a week, eat only one. When the social norm reduces to one pound, eat less and substitute chicken for beef because it is more earth friendly, and reduce your consumption of chicken when even greater earth friendliness becomes the norm. Eat more fruits and vegetables, but recognize that all consumption, even vegan consumption competes with the access of wild plants to habitat and other animals to food.
Such competition is part of the system. But you can reduce what you take from the system out of humble recognition that the whole system isn’t about you and other human beings. Its origins are mysterious and its ways inspire wonder. So, enjoy nature’s gifts as well as human fellowship in food as your path evolves toward ever more earth-friendly consumption.
Finally, be the change, please don’t be a fellowship-impairing scold.
About the Author
Peter S. Wenz is an Emeritus Professor of Philosophy who was recognized as a University Scholar of the University of Illinois largely due to his publications, which now include eight books that can be found at large Internet booksellers. He’s a non-dogmatic atheist (he knows he could be wrong – one of the advantages of marriage) and is an active member of Temple Israel, a conservative Jewish congregation in Springfield, Illinois (not the home of the Simpsons). His latest work, still in manuscript, (no joke here) is An Atheist’s Guide to Belief in God. Visit his blog, “Critical Divides: Both Sides in 800 Words,” at peterswenz.com.
