“Look at Mother Nature on the run in the nineteen seventies.”
– Lyrics from “After the Gold Rush,” by Neil Young, 1970.
1970 was a heady year for the environmental movement. With the birth of the Environmental Protection Agency and enactment of laws such as the Clean Air Act, a new chapter in the history of the nation was opened. The first Earth Day was celebrated in the spring of that year. And informed and motivated by these events, I began my university studies in engineering, mathematics, physics, chemistry, and molecular, cellular, and developmental biology in the fall of 1970. I had spent much of my childhood playing in the woods and boating on the river in my handmade kayak, and I wanted to dedicate my aptitude in math and science to help protect and preserve what I had so much enjoyed in my youth.
Two years earlier, Stanford University Professor Paul R. Ehrlich and his wife Anne had published The Population Bomb. And while I was a sophomore at the University of Colorado, The Limits to Growth hit the bookstands in 1972, authored by the wife and husband team of Donella and Dennis Meadows and their collaborative group of scientists working at MIT. In these seminal works, the authors sounded the alarm. If we continued blindly on the agricultural and economic paths we were on, humankind will soon march into a grim future of widespread famine and environmental collapse.
Now, a half century later, I wish to take stock on how well we have done in addressing their concerns and offer a few suggestions, both practical and theoretical, regarding what we can do today to keep these twin threats at bay.
To begin, I wish to set the stage by asking a question. How many people can live on this planet relying solely upon the bounty of the wild Earth? Stated in another way, what is the Earth’s carrying capacity for humans—the maximum, sustainable global population the world can support if we were all to live as hunter-gatherers?
The answer to this question provides enlightening context regarding the vital importance of agriculture. It also provides useful insights into how we ought to respond to many of the environmental justice challenges facing us today.
Humans have lived more than 90 percent of our existence as hunter-gatherers. Prior to the advent of agriculture some 10,000 to 15,000 years ago, we survived upon a paleo diet gleaned from locally available fruits, nuts, seeds, leafy vegetables, roots, insects, fish, and game.
So how many hunter-gatherers can the Earth support in its pristine state? According to the authors of peer-reviewed research published in the Proceedings of the National Academy of Sciences, “We estimate the global population of hunter-gatherers to be on the order of ~10 million.”
10 million people. That’s all.
More than 30 cities worldwide have a population bigger than that! Tokyo has 37 million residents, Dehli has 32 million, Shanghai 29 million, and 22 million people each live in Dhaka, Sao Paulo, Mexico City, and Cairo.
From a global perspective, population is growing at an annual rate of 80 million people, or about 1 percent a year. This rate is half of what it was back in 1968, when growth was romping ahead at 2 percent a year. In 1968, the world’s population stood at 3.55 billion people. We are on track to reach a total population of 8 billion people worldwide by the end of 2022.
Taken together, these data indicate that, each and every year, our increase in population alone exceeds the Earth’s natural carrying capacity by 8-fold. And they show that our total population is now 800 times greater than what can be sustained on Earth if we all ate a paleo diet foraged from wild sources.
How have we achieved this enormous increase in our population above Nature’s sustainable levels? Through better sanitation, health care, and controlling the release of toxins into the environment. But the principal, overriding reason is our adeptness at directing, on a massive scale, the biological productivity of Earth toward foods we can consume.
The miracle of modern agriculture—powered by sophisticated machines running on fossil fuels, improved irrigation, widespread application of chemical fertilizers and pesticides, and genetic developments that result in huge improvements in yields per acre—was not anticipated by the authors of The Population Bomb and The Limits to Growth.
And yet, all is not rosy. To feed our burgeoning population, agricultural operations now comprise 50 percent of the world’s arable lands—lands that were formerly wild grasslands, shrubland, and forests. It has become so encompassing that the flora and fauna of the planet resemble more and more what we choose to grow.
For example, to satisfy our rising appetite for food, we have leveled one-third of the world’s forest to make way for more farm fields and animal pasture. Of all the mammals alive today, 60 percent are domesticated livestock, and 36 percent are humans. A mere 4 percent of all mammals—lions, tigers, bears; ocelots, orangutans, and otters—are wild (when measured in terms of biomass). Agriculture’s transformational impact on the world’s bird populations is also startling. Today, 70 percent of all birds are domesticated poultry. Only 30 percent of birds winging in the world are wild and free (again measured on a weight basis).
Additionally, agriculture and the global food system are responsible for one-third of all greenhouse gas emissions to the atmosphere (a problem largely unanticipated back in 1970). And, agriculture is the world’s largest consumer of fresh water supplies. For example, in drought-stricken California, roughly 80 percent of all commercial water usage is directed toward irrigating more than nine million acres of farmland under cultivation. Only 20 percent goes to manufacturing, urban, and residential use.
In summary, through hard work and innovation, the world’s food supplies have kept pace with growing demand. But we are in a precarious position. To put it bluntly, if we were to suddenly stop intensive, continuous, cultivation of crops and grazing of animals, more than 99 percent of us would soon starve to death. And it is agriculture that is the greatest contributor to the mass extinction event currently underway.
So, what can we do? Bear in mind that we have no historical experience in such an enterprise as this. It is a little like using my experience of building my kayak by hand as a guide for fabricating a 3,000-guest ocean liner. Nevertheless, here are a few helpful suggestions out of the many adaptations already being implemented.
Enlarge our aesthetic sensibilities of what is beautiful in a landscape to incorporate what is bountiful.
Transform the spaces around our private homes, apartment buildings, and office parks so they become more welcoming to native insects, birds, and other wildlife, as appropriate. Using the principles of permaculture, cultivate more perennial plants that provide nuts, fruits, and berries for us and for wild creatures. Grow more vegetables locally in private and communal gardens.
Eat lower down the food chain. Maize, rice, root vegetables, and potatoes each provide about 1,000 kilocalories of nourishment per square meter of land. In contrast, beef cattle, lamb, and mutton each require more than 100 square meters of land to provide the same 1,000 kilocalories.
Implement more biodynamic, regenerative agriculture practices throughout all farming enterprises. The Virginia Association for Biological Farming (vabf.org) is to be commended for their efforts in this regard.
And finally, on a more theoretical level, we need to stop thinking about pursuing carbon capture and storage (CCS) to ameliorate rising CO2 levels and instead start thinking about carbon capture and use (CCU). We need to mimic photosynthesis by extracting carbon dioxide from the atmosphere and using it as the raw material (as Nature does) for making all things organic, including food.
To re-wild the world, reduce water consumption, restore wildlife populations to healthy levels, and eliminate CO2 emissions to the atmosphere, would I be willing to live in a post-agricultural era? Sitting around the dinner table, would I find palatable meals obtained from hi-tech, state-of-the-art food factories, powered by carbon-neutral, next-generation nuclear power? I’ll have to think about it.