August 10, 2009 Ukiah Valley, Mendocino, North America
After all [the] deeply depressing news… there are some reasons for optimism. One of them is that the transition to organic, sustainable, small-scale agriculture by millions of people in the US and billions world wide could do an enormous amount to mitigate the consequences of climate change. Becoming a small farmer is not just a good idea for your own security, you might actually save the planet doing it. As agrarian activist Vandana Shiva has put it, all of our emphasis on lowering carbon fails to recognize that we need more carbon — in soils — and that the power of locally adapted agriculture is the “only adaption strategy that gives us any hope.”
There are a number of ways in which small-scale, relocalized, sustainable agriculture can help sequester carbon and prevent it from being put into the atmosphere to begin with. The first, and most obvious, aspect is that the transportation of food over long distance makes a tremendous contribution to burning carbon. Delicate produce is often shipped by air from Israel to the US or New Zealand to Britain. Air travel, besides emitting large quantities of carbon, creates contrails that increase the effects of global warming. When your kiwi fruit or grapes travel from overseas, it is as if someone drove them to you in a low-mileage Hummer with the windows open and the A/C on.
Whether flown or trucked, all industrial food has a heavy carbon impact. Food is fertilized with fossil fuels, including artificial nitrogen, which creates the potent greenhouse gas nitrous oxide. Pesticides are manufactured with and from petrochemicals. Soil amendments are trucked around the world, then added to soils with carbon-spewing tractors. The food is often harvested mechanically, packed into warehouses cooled with fossil fuels, and then trucked, shipped, refrigerated, processed in every way, each with its carbon impact, until the day you drive to the supermarket to buy it. Moving the food economy home eliminates many of those stages. The need for pesticides and chemical fertilizers is reduced or eliminated. There is no need for warehousing, shipping or energy intensive preservation techniques that allow the food to spend a week or ten days in transit from field to table. When you walk out your door or down the street to a neighbor to pick up your eggs and vegetables, you spare the earth tremendous consequences.
Industrial livestock farming is one of the largest contributors to global warming. Researchers at the University of Chicago have calculated that the impact of switching from a normal, American meat-eating diet to a vegan one would save significantly more carbon than converting our car fleet to hybrids. The climate change effects of industrial meat production is enormous — both because animal feces is the largest source of methane (one of the most potent warming gases) in the US and because it takes a great deal of grain to produce meat. It takes about 15 pounds of grain to produce 2 pounds of industrial beef, almost 9 pounds to produce the same amount of industrial pork, and 4.5 pounds of grain to produce 2 pounds of chicken. Add to that the shipping and transport costs of moving cows and chickens and meat around, of slaughterhouses and manure disposal, and it becomes clear that what we eat is destroying our children’s future.
Reducing meat consumption is difficult for many people who are accustomed to lots of hamburgers. But a garden can be a good way of transitioning to a vegetarian or less meat-intensive diet. The sheer good taste of the food makes the flavors of meat less necessary. Moreover, livestock raised on pastures, eating the foods they are meant to eat produce considerably less methane while also adding their manures to the soil and increasing the ability of pastures to sequester carbon. Less meat, raised sustainably in integrated agriculture is necessary to prevent runaway climate change.
Besides the many ways that becoming a nation of farmers can reduce our carbon output, the practice of sustainable agriculture can actually reduce existing carbon in the atmosphere by raising the levels of soil humus. We do this every time we add compost or mulch to our ground, every time we choose not to till or plow, and leave soil undisturbed. For large-scale grain farming, UC Davis Professor Johan Six estimates that 80 to 200 million tons of carbon could be pulled out of the atmosphere and sequestered in the soil by the use of conservation tillage, which reduces soil disturbance and requires fewer tractors and less oil and gas. We could reduce carbon in the atmosphere at present by 5 percent or more simply by raising the level of humus in agricultural soils and reducing tillage. Doing so would also repair badly depleted farmland, damaged over the years by industrial agriculture.
More carbon still could be removed from the atmosphere if we were to raise the levels of humus in the millions of acres in the industrialized world that consist of back and front yards; public green spaces; office parks; church, synagogue and mosque grounds; and the White House lawn. The average residential home sits on slightly less than one quarter of an acre of land. By adding all the residential yards and commercial green spaces, public parks, etc., there are more than 7 million acres of green space in the US with soils that could be enriched to hold carbon.
In fact, this return of carbon to soil has even greater possibilities, as David Holmgren, co-originator of permaculture and author argues in Permaculture, Principles and Pathways Beyond Sustainability. Holmgren notes wisely,
Concern about the greenhouse effect has combined with the understanding that trees store carbon to produce a huge increase in research into “carbon sequestration” by trees. The interest in using trees as a “sink” to get rid of unwanted atmospheric carbon dioxide has increased awareness, as well as scientific knowledge, of the role of trees in storing carbon. From a permaculture perspective, the debate and activity is back-to-front; it focuses on the problem: carbon dioxide pollutions, rather than on carbon as a source of fuel for new life.
Though it is not clear how much carbon is sequestered by trees in temperate climates, forests create soil humus naturally by dropping leaves and building soil that way. But Holmgren is right on target in that we need to think about ways that atmospheric carbon can be used to compensate for the agricultural losses of global warming. Recently, Gaia Theory creator James Lovelock argued that the only really viable remaining solution to climate change would be the transformation of our agriculture so the soil could hold more carbon. “It would mean farmers turning all their agricultural waste — which contains carbon that the plants have spent the summer sequestering — into non-biodegradable charcoal, and burying it in the soil. Then you can start shifting really hefty quantities of carbon out of the system and pull the CO2 down quite fast.” In this model, our destructive agriculture is transformed into something fundamentally regenerative — and enormously helpful.
What is needed to do this is simply a commitment to return organic material to the soil and to cease rototilling and plowing to disturb it. Instead, we would return all of our spare organic material — leaves, food scraps, animal manures, waste hay and straw, weeds that have not gone to seed — to our soil in the form of sheet mulch (that is, lots of dry material like straw or leaves spread over the ground and nitrogen-rich materials like manures, food scraps, coffee grounds and grass clippings mixed in) or as compost. Instead of tilling, we would plant directly into mulched ground. This keeps the carbon sequestered. As levels of soil humus rise over the years, more atmospheric carbon would be removed.
Every one of us with any soil can do this — your tiny backyard or your giant farm can reduce the impact of global warming that we’ve already created. And by growing food and living locally, you can cease putting food-related greenhouse gasses into the atmosphere.
Growing our own food may be the single most important way any of us can preserve the planet from climate change.
See also A Growing Revolution – Urban Gardens Are Changing The Landscape→
…and our sister blog OrganicToBe→