What's Left to Eat?

Sustainability: Can We Keep Doing What We're Doing?

Agriculture has changed more in the past five decades than during the previous 10,000 years. These changes have brought many benefits—and heavy costs. Can we sustain our modern ways of growing food?

These are just a few of the books that have spurred people to take a fresh look at our choices, our lives, and our impact on the Earth.

Henry David Thoreau
Walden, 1854

This American classic describes Thoreau's experience living in a cabin near Walden Pond in Massachusetts. "Our lives are frittered away by detail," he warned. "Simplify, simplify."

Aldo Leopold
A Sand County Almanac, 1949

"We abuse land," wrote this conservation pioneer, "because we regard it as a commodity belonging to us. When we see land as a community to which we belong, we may begin to use it with love and respect."

E.F. Schumacher
Small Is Beautiful: Economics As If People Mattered, 1973

"We are estranged from reality," argued this European economist, "and inclined to treat as valueless everything that we have not made ourselves." Escaping that self-destructive attitude, Schumacher said, would require "studying the possibilities of alternative methods of production and patterns of living."

Wendell Berry
The Gift of Good Land, 1981

A farmer, Berry advocates sustainable agriculture: "I have seen enough good farmers and good farms, and a sufficient variety of both, to convince me that an ecologically and culturally responsible agriculture is possible."

Michael Pollan
The Botany of Desire: A Plant's-Eye View of the World, 2001

Not yet a classic, Pollan's stories examine our relationship with four items, including the potato and apple, trace the development of current food-growing practices, and offer practical alternatives. He questions if humans have domesticated plant species or whether plant and animal species have cleverly manipulated us to advance their own interests.


What is sustainability and why does it matter?

One way to start exploring this crucial topic is to picture a fish tank. Keeping its occupants alive takes work. Besides feeding the fish each day, an aquarium owner must make sure the pump, filter, and heat lamp are working. Fish tanks also require regular cleaning. These actions are essential for sustaining life in the aquarium. If the owner neglects the aquarium, the fish will die. It's that simple.


Source: NOAA
Source: National Oceanic and Atmospheric Administration


Like a fish tank, Earth is a closed system. But unlike fish, we can make decisions about our impact on the system in which we live. Our survival on this planet, in fact, depends on facing two inescapable realities:

  • We can't add anything. Our "aquarium" has a finite amount of matter—soil, rock, water, and so forth. Besides energy from the sun, whatever we produce or consume comes ultimately from materials on the planet. If we use up something—oil supplies, for instance—there's no way to get more.
  • We can't subtract anything. We talk about throwing things away as a solution, but there's really no "away" in our global ecosystem. Matter may change form, as when fire turns solids into gases. But nothing truly disappears. If we create pollution that natural forces can't break down, we're stuck with the mess.

Sustainability is living in a way that keeps our "aquarium" in good shape. It means using resources wisely, allowing nature to replenish itself, and cleaning up after ourselves. It means meeting the needs of the present without compromising the needs of future generations. This may sound like idealistic ecospeak. But it's actually the only realistic long-term way to preserve our habitat—and our health.

Fortunately, many natural processes help keep the Earth healthy. Bacteria and other microorganisms decompose organic wastes. Trees and plants consume carbon dioxide and create oxygen. But humanity now produces more waste than such natural systems can handle. We've also created dangerous substances that break down extremely slowly—or not at all. These actions threaten the planet's long-term health. In other words, they're unsustainable.


Modern agriculture offers many examples of unsustainable human actions. We are losing soil and using water much faster than nature can replace them. We are also using pesticides, fertilizers, and other substances in amounts that far exceed nature's ability to decompose or assimilate them. And the trend of focusing on a small number of cash crops has led to what scientists call genetic erosion.

No other species would purposely spoil its own environment. Here are a few ways that we are affecting our resources:

  • SOIL: Farming techniques, such as planting the same crop year after year or planting on steep slopes, can significantly increase the likelihood of erosion. As a result, wind and water can carry off tons of valuable topsoil. Replacing even a centimeter-thick layer can take up to 1,000 years, depending on the location.
  • WATER: Forty percent of the world's food comes from irrigated crops. To get water for irrigation, we are emptying surface aquifers much faster than nature can refill them. We're also tapping deep, underground aquifers in ways that either nature can't replace or can do so only slowly. Each year, for instance, one must go a meter deeper to reach the Ogallala aquifer, which is crucial to farming in the midwestern U.S.
  • ENERGY: Industrial agriculture relies on heavy machines, which guzzle huge quantities of irreplaceable fossil fuels. Processing and shipping modern food products also requires large amounts of energy. Many pesticides and fertilizers, moreover, include petroleum-based ingredients.

This extravagant approach to using up Earth's resources should make us stop and think. Is our current food production system really sustainable? Many scientists warn that it isn't.

video_iconMeet a French farmer struggling to farm in a sustainable, centuries-old way.
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Source: Journey to Planet Earth


"Insanity," the old saying goes, "is doing the same thing over and over again, and expecting different results." With that in mind, some agricultural experts say it's time for a whole new approach to farming. They advise shifting from industrial agriculture to sustainable agriculture. The chart below illuminates the two approaches.

Industrial Agriculture
Sustainable Agriculture
VISION: Farming is a commercial activity, and agricultural technology helps us overcome nature. VISION: Farming is a way of life, and working with nature is the best approach.
SOIL: Fields are like factories—a place to produce something. Fertilizers can replace any nutrients lacking in unhealthy soil. Deep plowing breaks up soil and leaves it vunerable to erosion. SOIL: Fields are home to an intricate biological community, including crops, bugs, and microbes. Careful choices are needed to keep soil healthy. In no-till or low-till methods, earthworms and deep-rooted plants can break up soil.
CROP CHOICE: Monoculture, or growing a single crop, is more efficient than raising different types of plants or rotating them. Government programs can dictate what crops are grown. High-yield crops earn farmers the highest income. CROP CHOICE: Rotating crops replenishes soil. Polyculture, a mix of crops, benefits from symbiotic relationships among species. Choosing crops that suit the climate reduces irrigation and risk of disease.
CROP TRAITS: Produce growers prize varieties that ship well, have a long shelf life, look good, and appeal to mass market consumers. CROP TRAITS: Farmers stress taste and adaptability to local conditions in selecting plants to raise. Farmers often sell locally.
FERTILIZER: Large doses of synthetic products not produced by the plants or animals already on the farm provide nitrogen, phosphorus, and potassium (N-P-K). FERTILIZER: Farmers pay attention to soil biology and minerals already in the ground, which lessens the need for synthetic fertilizers.
PEST CONTROL: Synthetic pesticides, often used in large amounts, kill far more than the targeted pests, which often grow resistant to the chemicals. This can create new and worse problems. Farmers turn to genetically-modified seeds that resist disease. PEST CONTROL: Farmers seek ecology-based, nontoxic remedies. These may include introducing companion planting (growing a plant that repels another plant's pests) or insects that will eat pests.
WATER: Irrigation moves large amounts of water to high-yield crops. This often "mines" aquifers, which aren't replenished by rainfall. Salinization further destroys farmland. WATER: Farmers use drought-resistant plants and crops that shade soil, reducing evaporation of water from the soil.
POVERTY: Corporations, trade regulations, and other government policies impoverish farmers in developing countries, who turn to slash-and-burn farming that harms the soil. POVERTY: Fair competition helps even poor farmers find a market for their crops.


Contour plowing. Source: USDA SARE Program Cows grazing. Source: USDA SARE Program
Contour plowing and cows grazing freely reflect sustainable agricultural methods.
Source: USDA Sustainable Agriculture Research & Education (SARE) Program



Advocates of sustainable farming offer various suggestions for growing food in an environmentally sound way.

Sprouting wheat plants. Source: Natural <span>Resources</span> Conserva<span>tion</span> Service
Sprouting amid the remains of old wheat plants, these soybeans exemplify two forms of sustainable agriculture: crop rotation and no-till farming.
Source: Natural Resources Conservation Service
  • Rotating crops each year can reduce the need for chemical fertilizers. That's because different plants use different soil nutrients. Some crops actually put nitrogen—an important nutrient—back into the soil. This is called nitrogen fixation.
  • By recognizing the life cycle of pests, crop rotation can lessen or eliminate farmers' reliance on commercial pesticides.
  • Plowing less often, or not at all, minimizes erosion and helps keep topsoil in a healthy, natural state with diverse population of organisms.
  • Growing a variety of crops limits the extent to which disease, pests, or price drops can wipe out a farmer's income.
  • Periodically moving cattle and other livestock from field to field (a practice called rotational grazing) gives land a chance to recover from the animals' grazing and is a natural way to spread manure. Moving within the same field helps keep animals disease-free, and reduces the risk of meat or milk contamination (as with Mad Cow disease).


Agriculture is a huge industry, so changing it may seem impossible. Yet many farmers around the world are choosing to raise food in more sustainable ways. A few encouraging examples:

  • More and more farmers have adopted low-till or no-till methods. The amount of U.S. farmland tilled in earth-friendly ways rose from 15 percent in 1980 to 35 percent in 1993.


Pioneering role in farm conservation. Source: Natural Resources Conservation Service
Their pioneering role in farm conservation brings sober pride to South Carolinians.
Source: Natural Resources Conservation Service


  • As a result to such practices, the USDA claims that the topsoil erosion rate for an average American farm dropped from 7.3 tons a year in 1982 to less than 5 tons in 1997.
  • Many farmers report that they were using far fewer chemical pesticides than before. Organic food sales in the U.S.alone rises significantly each year.
  • More countries are labelling food products to help us make important choices.

Such improvements are a start, yet a widespread embrace of sustainable agriculture remains a distant goal. Individuals and governments must care enough to make changes.


health_iconDoes genetic erosion matter? If so, what is it?

science_iconWhat can we learn from the lab on the prairie?


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