Ground Zero for Carbon Dioxide Reduction Is the Ground
The process that actually removes CO2 from atmospheric circulation is photosynthesis.
—Christine Jones, Australian soil ecologist
WE’VE GOT A CARBON PROBLEM. Scientists tell us we’ve already passed the safety threshold for the concentration of carbon dioxide in our atmosphere. To avoid destabilizing the climate and provoking other associated catastrophes, we need to bring that down to 350 parts per million. Right now we’re at 392 and creeping upward.
While we strive for “carbon neutrality” and scratch our heads over proposed carbon trading schemes, the problem isn’t the amount of carbon per se—the quantity of carbon on earth is constant—but where that carbon is. The surplus, climate-stressing, troublemaking stuff is what enters the atmosphere when it combines with oxygen to form carbon dioxide gas.
Well, where are we supposed to put all that extra carbon?
Into the soil. Carbon is what lends fertility to soil and sustains plant and microbial life. Soil that’s rich in carbon holds water, like a sponge. By contrast, water that falls on soil depleted of carbon streams off, causing erosion and leaching out nutrients. Land that retains water is more resilient to drought, wildfires, and flooding. In the words of Christine Jones, an Australian soil ecologist known Down Under as “the carbon queen,” “Carbon is the currency for most transactions within and between living things. Nowhere is this more evident than in the soil.”
Our crisis of excess atmospheric carbon dioxide is real and urgent.1 It’s a problem the likes of which we’ve never seen, at once invisible and global, abstract and yet far-reaching in consequence. But by focusing our efforts as we have been on the atmospheric component—trying to cap the lid on what we’ve been spewing into the air—we’re only seeing half the picture. The other part of the story is that much of the legacy carbon hovering in the atmosphere is supposed to be down in the soil.
This knowledge sent me on a quest to learn more about “soil carbon”— a phrase that under ordinary circumstances would be a cue during a science lecture that it was time to drift off. And so I spent the better part of two days with two men devoted to the cause of soil carbon: Peter Donovan and Abe Collins, founding members of the Soil Carbon Coalition, a nonprofit whose mission is to “advance the practice, and spread awareness of the opportunity, of turning atmospheric carbon into soil organic matter.” The tagline on the group’s website reads: “Put the carbon back where it belongs.”
Peter was passing through Vermont as part of the Soil Carbon Challenge, a competition to gauge how well land managers can facilitate the biochemical magic of drawing carbon back into the soil. The idea is to measure the baseline carbon levels on the properties of “contestants”—among them ranchers, farmers, and environmental nonprofits from California to Iowa to the Carolinas—and retest and document changes over the course of ten years. By focusing on small, fixed areas, the Soil Carbon Coalition organizers can monitor soil carbon changes accurately and with minimal cost using well-established methods of field sampling and laboratory testing.
How do you build carbon in the soil? By reversing the processes that released carbon into the air. Oil, coal, and gas represent one source of emissions, but over time the greater culprit has been agriculture. Since about 1850, twice as much atmospheric carbon dioxide has derived from farming practices as from the burning of fossil fuels (the roles crossed around 1970). In the past 150 years, between 50 and 80 percent of organic carbon in the topsoil has gone airborne. The antidote to this rapid oxidation is regenerative agriculture: working the land with the goal of building topsoil, encouraging the growth of deep-rooted plants, and increasing biodiversity. This turns the conventional approach to farming upside down: Rather than focusing on growing crops, the intention is to grow the soil. But “carbon farmers” like Donovan and Collins contend that as you build carbon levels, the rest—land productivity, plant diversity and resilience amid changing conditions—will follow.
Peter, fifty-nine, a soft-spoken former sheep farmer and scholar of classics and music, took the challenge on the road in July 2011. He gave up his apartment in Enterprise, Oregon, along with the bulk of his worldly goods and set out in a refitted 1981 school bus to monitor the nation’s soils. He had several scheduled monitoring stops as he trekked east, but left time open to give talks and workshops and recruit more land managers and landowners to the competition. The monitoring and lab work cost $250, and, as he admits, offer no direct financial gain to participants—only the chance to be part of an effort to improve the land and environment.
One day in late October I drive up to St. Albans, Vermont, where Abe Collins is managing about 185 acres, most of which is used for cattle grazing. The air is raw and chill; the gray-on-gray sky hints at the freak early snowfall that will hit Vermont later in the week. The hills all around are dominated by the “burnt” colors (burnt umber, burnt sienna) that I remember ruled the rarefied autumnal corner of the crayon box. I wait in front of a farmhouse by the big yellow bus, with Oregon plates and a sign that reads whole grasslands build soil, as well as an offer to tune pianos for a reasonable fee, until a John Deere Gator rattles up. Abe, a younger man in jeans, jumps out and welcomes me. He wears a green-rimmed baseball cap with the words plays in the dirt. He looks down at my feet and frowns. “It’ll be pretty wet out there,” he says, and goes inside his house to find some women’s boots he has around, one pair of which fits well enough. The fields, he says, are still saturated after the flooding from Hurricane Irene, almost two months before.
We ride the ATV toward Lake Champlain, a cool blue marker just over a mile away, and stop at a back pasture. I watch the two set up a transect and lay out a four-by-four-meter (thirteen-by-thirteen-foot) plot. They put down a metal hoop to create a kind of spatial “snapshot” that will allow them to zero in on a microcosm of the field. Peter and Abe kneel down and take a read of the land.
“There’s dandelion, Italian ryegrass, blue grass—Kentucky and Canadian,” Abe reports. “Meadow fescue. Clover, red and white. Very small amount of reed canary.” All I can see is a bunch of grass with the occasional dandelion leaf bouquet.
The diversity of plants, Abe tells me, indicates the improved condition of the land. “When we started on the land, about six years ago, it was pretty badly drained and swampy.” At the time, he explains, it was dominated by reed canary grass, an invasive species that has been driving out native plants in many parts of the United States, including Vermont. “I started loosening soil with a subsoiler, then grazed it and grazed again. Took hay crops, spread compost, laser-leveled it with a large plane, used a Keyline plow to aerate it. Before, the topsoil was four to five inches thick. At that point you got to an orange zone, the bottom of the topsoil where it’s alternately aerobic [with oxygen] and anaerobic [without it].”
Abe shows me what soil at the oxygen threshold looks like: mucky wet clay with seams of rusty orange running through.
He continues: “Now there’s eighteen inches of topsoil. We changed the conditions so there’s oxygen and looser soil.” And a greater variety of grasses and other plants, which reflects the land’s ecological health and resilience.
Even more important than plant diversity is the fact that there are plants there at all, as opposed to bare ground. In soil carbon terms, that’s a no-no. As Peter says, “Bare, uncovered soil indicates that there’s not only leakage of soil carbon into the atmosphere, but the absence of life that can replenish it.” Think of the huge tracts of agricultural land after corn or soybeans have been gathered up, all that naked dirt lying there as carbon wafts into the sky. Once you get thinking in terms of soil carbon, you’ll never look at a harvested field the same way again. What might once have looked rustically beautiful and peaceful—quiet, golden fields; geometric ripples from the plow and combine—now seems, at least from a climate perspective, somewhat menacing.
Of the pair, Abe, in his late thirties, is the upbeat, can-do, jaunty one. He has pale blue eyes and smooth, fair, boyish skin, and likes to kid around. At one point he kneels down in front of a freshly made hole and says, “That’s what a worm looking upward sees—except that they’re blind.”
The two men mark out their grid with meter sticks capped with red flags. Peter lifts up a hunk of sod. As he digs deeper, the shovel makes a slurping, gurgling sound. “These soils are saturated,” he says. I’m glad I borrowed those boots.
They do their work in earnest, Peter prepared with his knee pads, serrated knives, tin cans for the cylindrical shape, and an old-fashioned wooden classroom ruler. (“Top-grade state-of-the-art research here,” he says drily.) He collects the soil samples in ziplock plastic bags and places them in a canvas sack with the words A NATION THAT DESTROYS ITS SOIL, DESTROYS ITSELF—the FDR quote that inevitably surfaces on T-shirts, publications, and email tags when you’re dealing with soil champions.
I stand in the open field, feel the sun begin to withdraw its feeble late-fall warmth, and muse about what these guys are doing. Marking the land with posts and red flags, poking around in the dirt. And later, for Peter, the tedium of dealing with samples and data in his yellow school bus home. What’s driving these two?
For one thing, they want to raise public awareness of soil’s potential for absorbing carbon. According to Christine Jones, soils hold more carbon than the atmosphere and all the world’s plant life combined—and can hold it longer, in a more stable form than, say, trees. She says that a soil carbon improvement of just 0.5 percent in the top twelve inches of 2 percent of Australia’s agricultural land would effectively store that country’s annual carbon dioxide emissions over the long term.
Here in the United States, Rattan Lal, of Ohio State, has estimated that globally soil carbon restoration can potentially store about one billion tons of atmospheric carbon a year. This means that the soil could offset about one-third of the human-generated emissions annually absorbed in the atmosphere. This is not some nifty trick, a way to cheat on nature; it’s simply replacing soil carbon that has been lost over millennia. According to Lal, the carbon pools of most of the world’s agricultural soils have been depleted between 50 and 70 percent. From man’s earliest forays into agriculture about ten to thirteen millennia ago, that amounts to some fifty to one hundred billion tons of carbon. “Restoring the depleted carbon pool in agricultural soils is essential to enhancing agronomic productivity for feeding the world population, and to improving the environment,” says Lal. “It is a truly win–win option. The strategy of restoring carbon in world soils buys us time. It is a bridge to the future until alternatives to fossil fuel take effect.”
Some folks make even bolder claims. Ian Mitchell-Innes, a South African rancher and trainer in Holistic Land Management, told me, “If we improve 50 percent of the world’s agricultural land, we could sequester enough carbon in the soil to bring atmospheric CO2 back to pre-industrial levels in five years.”
Abe expresses it this way: “Worldwide, if the organic matter—which is about 58 percent carbon—in all the land that we currently farm and graze were increased 1.6 percent to a foot in depth, atmospheric CO2 levels would be at pre-industrial levels. We’ll have to do even better than that for many reasons, including if we want to get below three hundred parts per million of CO2, since annual global carbon oxidation exceeds photosynthesis.” He cites Allan Yeomans, author of Priority One: Together We Can Beat Global Warming and a longtime proponent of an agricultural solution to climate change, as inspiration for his soil carbon advocacy.
Whatever angle you take on this and whichever statistics you highlight, climate-wise the stakes are huge. Yet the notion of soil carbon has barely made a dent in our national or international conversations about climate change. And as Abe points out, even if we stopped emissions 100 percent (an occurrence that, given how global climate meetings play out, remains firmly in the realm of the hypothetical) but kept the same agricultural practices, we wouldn’t be able to bring down carbon dioxide levels for a very long time. By itself, stopping emissions is insufficient. That carbon has to go someplace. As the Soil Carbon Coalition argues, it might as well go into the soil, where it can do some good.
Peter Donovan has gray hair, blue eyes, and the serious demeanor of someone who broods over things like photosynthesis and the cycles of greenhouse gases and the folly of man. He’s compact, not tall, but tall enough that living in 190 square feet is a squeeze. Still, he flatly turns down any offers of accommodations. “The bus is my home,” he’ll say, matter-of-factly. I sit in the bus and drink chamomile tea while he oven-dries (that is, he microwave-oven-dries) soil samples so as to measure soil density, a necessary factor in gauging the mass of carbon in the soil.
Peter’s school bus has a small woodstove, a solar water heater, and a sawdust bucket toilet. There’s a bed and sitting area, along with an Oriental carpet and a fine upright piano (Bach’s “Englische Suite” is on the stand) and a reading nook (awaiting attention: the latest translation of War and Peace). “The thing I love about living here is the light,” he says. “When you sit down, you have almost a 360-degree view.” A little before six it grows darker and he puts on a headlamp so he can see his way as he moves around. That panoramic light fades, and the bus becomes a cozy room.
Peter is quick to note that he is not a soil scientist, which he sees as both an advantage and hindrance to his efforts: “It’s hard to get funding.” Because he’s not associated with a known institution, he says, the coalition’s work seems to make people uncomfortable. “I get asked, ‘Are you with a university?’ ‘How do I know that what you’re saying is true?’”
At the same time, he says, he has the freedom to ask questions and make connections that an institutional affiliation might not support. For example, the Soil Carbon Challenge measures carbon levels over ten years. Someone at a university, completing a PhD or seeking publication, has incentives to do research projects of no more than a few years. In government agencies and nonprofits, soil carbon work is geared to the “so-called carbon market.” And all organizations—this is a pet peeve of his—tend toward fragmentation, so that soil conservation and climate mitigation are seen as separate, even competing, campaigns. All this means that stories that don’t fit into a short time frame, aren’t linked to profitable ventures, and/or can’t be neatly tucked into departmental divisions may not get told.
It’s a quixotic journey Peter’s embarked on, seeing the country through the flat, broad windows of a bus, promoting ecological knowledge from outside the research and nonprofit establishment. And a somewhat roundabout way that he got here. After graduating from the University of Chicago, he worked in eastern Oregon herding sheep and cattle. In the 1990s, he trained in Holistic Management (HM) and met Allan Savory, the Zimbabwean rancher, wildlife biologist, and all-around maverick who developed the model. HM is based on Savory’s observation that livestock can play a role in land restoration—that grazing animals, such as cattle, can be applied to land as a “tool” to improve it. (Savory officially enters our story in chapter 3, “The Making and Unmaking of Deserts.”)
“Everything Savory said made complete sense to me,” says Peter. Holistic Management became his intellectual base, informing his perspective on our advancing ecological plight. He traveled around the country and abroad, to Mexico and southern Africa, meeting HM practitioners, including Abe, and writing about his observations. Then in 2007, at a talk in Albuquerque, a researcher from the Natural Resources Conservation Service (NRCS), a government agency, told the audience that management made no difference to the accumulation of soil carbon and it was too hard to measure anyway. (That seems not to be the NRCS party line.) “That ticked me off,” he recalls. “It was sort of a call to action. Abe and I had been kicking around a lot of ideas, so we started the Soil Carbon Coalition.”
Abe, who has by now joined us after taking care of whatever mysterious tasks someone who manages a hundred-plus acres of land might have to do, grew up in central Vermont. In the 1990s, he lived in the community of Hard Rock on the Navajo Nation Reservation in Arizona where he studied and practiced agriculture, including approaches like permaculture and Holistic Management that have a regenerative component. “I did land restoration work with a group of Navajo men and women who started an organization called the Black Mesa Permaculture Project,” he says. “There the basic line was: Our way of life depends on the land. It was ‘common knowledge’ that cattle and sheep, the way we were keeping them, were ruining the land, but when I talked to the elderly Navajo, they all said that the land was much better back when there were big herds and people herded the livestock in big, seasonal migrations.” When he ran across Allan Savory’s work using mega-herds of livestock to heal deteriorating land, places like Arizona’s arid Black Mesa, which has been heavily mined, “the lightbulb came on in a big way.”
Collins moved back to Vermont to apply these ideas to home turf. He keeps cattle and grazes them on land he manages—moving them from field to field according to Holistic Management principles, so that the fields are regularly but not overly grazed, trampled, and manured, then given time to regrow before being grazed again. For the most part their usual products, meat and milk, are incidental. Rather than, say, a dairy farmer or cattle rancher, Abe would be likely to describe himself as a grazier, a grass farmer, or even a carbon farmer.
They acknowledge that the day’s soil measurements, as well as all those on Peter’s cross-country swing, will do little to change land or minds. But this initial “baseline tour,” as the Soil Carbon Coalition calls it, begins the process of putting together data: the Holy Grail of science-based environmental advocacy.
“Getting carbon baseline measures is not a practical thing to do,” Peter concedes. “But we need real data. Not because people will make decisions based on that—because people don’t necessarily do that— but if we’re going to make a shift toward considering soil carbon a key to land function, we’ll need a place to stand, for example in tons of carbon gained or lost per hectare per year over a decade. Right now there’s not a whole lot of data, especially in terms of changes over time. The thing about data is that it can change our beliefs about what is possible and not possible. It can work on our imaginations, which is important because in our society we have a lot of conflict between the defenders of the impossible, those who say, ‘We can’t do it,’ and the artists of the possible.”
“We’re talking about building topsoil,” Abe breaks in. He’s restless. He wants to fix something, now. At the very least, he wants me to understand the vast implications of soil carbon: that bolstering soil carbon means adding organic matter to the soil, which means building topsoil—the precious growable layer of the ground we ply, where the biological magic of food and forage occurs. It’s been accepted as a given that topsoil forms over geological time; the figures generally bandied about are that it takes five hundred to a thousand years to generate an inch of new soil. But this refers to the slow weathering of rock—nature left to its own devices, without human interference. Actively working to stimulate soil formation—through maintaining ground cover, increasing biological activity, imposing levels of disturbance that add oxygen and moisture, as can be done with livestock— can accelerate the process. That is, really speed it up, to an inch or more a year. In regenerative agricultural circles, it’s been done. (We’ll see how in chapter 2.)
“Accelerated topsoil formation is the great work of our time,” Abe says, as in a proclamation. “It’s the centerpiece for addressing the environmental security and economic development issues facing all of us in one fell swoop. Now, is there an opportunity to build topsoil, or are we stuck with a thousand years needed to build an inch? In any complex system, you need to measure. So that’s where we start.”
In a conversation with Peter, one phrase that often comes up is managing toward. What he means is that in any management situation, there’s a difference between “managing for” something and “managing against.” He believes that one reason we—that is, we humans, or at least we modern, Western humans—continually back ourselves into a corner is that our impulse is to manage against. As one example, our approach to medicine is managing against disease rather than managing for health. This has helped bring us to a situation where we need increasingly bigger guns to fight off infection while a huge chunk of the population suffers from chronic disease or unnamed malaise. Managing for health, by contrast, would emphasize diet, exercise, avoiding toxins, and building immunity (chapters 5 and 7; discuss how soil plays into these factors).
He believes that this is why our carbon problem—the need to do something about rising stores of carbon in the air—leaves us stuck. We’re trying to manage against tossing more carbon into the atmosphere. What we can and should be doing, Peter argues, is to manage for a carbon cycle that does more work: splits more water and carbon dioxide and results in more water-holding, fertility-enhancing soil organic matter. Our current approach, which worthy and well-meaning environmental organizations have signed on to, has been to plead with would-be polluters to stop polluting. As a friend of his wryly put it, this strategy amounts to: “Let’s wreck the world more slowly.” This is a valid effort compared with the alternative—protecting nature where we can is essential—but hardly a route to lasting ecological soundness. However, Peter believes that by a shift in our thinking, we will start asking different questions and emerge with different solutions to the problem of carbon levels run amok. What we need is to tell the story of our predicament in a different way and keep ourselves focused on the notion of managing toward.
In his various stops along his travels by bus—he’s done about fifty-four hundred miles when I catch him in St. Albans—Peter gives occasional soil carbon workshops. Since Bennington is on the way to the Boston area, his destination after Vermont, I arrange for Peter to give a workshop here in town, which the One World Conservation Center, a relatively new environmental education center and reserve, housed in an old Hojo’s, kindly offers to host. I am expecting a rehash of what I’ve already learned, all the good news about soil carbon and why we should promote the building of soil carbon. I could sit back and occasionally nod knowingly. But no, this is a full-on theoretical lecture on the carbon cycle, and the historical forces that have interfered with our ability to see this universal, ongoing process—a mainstay of any high school science class, if handled in a perfunctory way—as a key to environmental restoration.
I can hardly hope to do justice to this tour de force on the history of scientific thought, but I’ll give it a go. Actually, I’ll do it twice: First, I’ll highlight some ideas that surface in our sweep through the natural sciences. Then I’ll do the bumper sticker version.
Peter starts by posing a question: Where does most of the mass of plants come from? Plants grow in soil, so most people think the answer is soil. Wrong! This was proved in the seventeenth century by Jan Baptist van Helmont, who grew a willow tree for over five years and found that the weight of the soil it grew out of had hardly changed. Water? That’s what the Flemish van Helmont thought. Nearly a century and a half later, a Swiss scientist, Nicolas-Théodore de Saussure, refined this experiment by enclosing plants in glass and monitoring the water and carbon dioxide given to them. He demonstrated that carbon in plants—the basis for plant organic compounds—was obtained from carbon dioxide in the air; the hydrogen in these compounds came from water. This set the stage for an understanding of photosynthesis, a plant’s ability to take in solar energy and combine it with water and carbon dioxide to make food and mass.
Photosynthesis is one of those things we all kind of know about, but Peter wants us to appreciate just what a powerful force this building-plants-from-carbon-dioxide trick is. “Life doesn’t just sit there,” he tells the group. “It does work. Nature is a process, not a collection of things.” We tend not to think of biological processes as work because they’re always going on in the background, slowly and quietly, at least to the extent that we can observe. If we define work mathematically, as force over distance, day in and day out the work of photosynthesis exceeds the total of the world’s industry by a factor of nine. Plants, then, move many times more carbon molecules than does the burning of fossil fuels.
Now we’re ready to take a look at the carbon cycle:
The carbon cycle is what we generally call the cycle of life: birth, growth, death, and decay, in which photosynthesis plays an important part. Photosynthesis uses sunlight to split water and carbon dioxide, and builds compounds that become food, fuel, and biomass. The reverse reaction is respiration, oxidation, or combustion—which in the 1780s French scientist Antoine Lavoisier recognized as similar processes. This other side of the cycle turns carbon compounds back into carbon dioxide and water and releases energy.
When we look at the carbon cycle in the context of soil, this is what we see: If carbon-rich soil organic matter is being oxidized by common bacteria in the presence of oxygen, the soil is losing carbon. This creates a negative feedback loop, with soils losing more carbon and water and plants struggling to grow. If, however, we’ve got more carbon in the soil, we’ve got fertile ground for plants, more photosynthesis, and a positive feedback loop that takes carbon dioxide out of the air. In our biological system, soil functions as a hub, or intersection, for the carbon cycle.
Starting to make sense?
At this juncture we switch gears and consider our carbon dioxide problem—that “inconvenient truth” of having too much carbon dioxide in the atmosphere, due in no small part to human activity. Understanding of this problem has to a great extent derived from the Keeling Curve, which was featured in Al Gore’s landmark documentary on climate change, depicting the concentration of carbon dioxide in the atmosphere. It is named for Charles David Keeling, a scientist at the Scripps Institution of Oceanography at UC San Diego, who began gathering carbon dioxide data in 1958. Since then, readings have regularly been taken at Mauna Loa in Hawaii. It is arguably among the world’s most recognizable scientific images.
Keeling’s emblematic diagram depicts carbon dioxide as a continuously rising line, with slight fluctuations to account for seasonal variations. For example, the line dips when it’s summer in the Northern Hemisphere, since carbon dioxide is drawn from the atmosphere by newly growing plants; during the North’s winter, with the seasonal decay of crops dying back and leaves decomposing, the rate of emissions ticks up again. The visual image of that slender line, relentlessly climbing upward on into the temporal frontier, can only evoke in the observer a feeling of anxiety and helplessness if not outright dread. If I drew up a graph of what happens to my blood pressure while looking at the Keeling Curve, it would look very much the same.
As Peter sees it, the message we take from the Keeling Curve is this: Carbon in the atmosphere traps heat. This is a problem of atmospheric pollution. The cause of this is the burning of fossil fuels. Therefore the solution is to reduce fossil fuel emissions. The implication—and the conclusion we accept—is that by curtailing emissions we will be rewarded with a moderating curve. However, according to the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report, if, in 2007, we completely stopped emitting carbon dioxide, it would take nearly a century to bring concentration levels down to 350 parts per million.
In other words, we learn that the way to deal with our carbon dioxide problem is through technology (low-carbon energy sources; whiz-bang contraptions to capture carbon), political will, or both: strategies that aren’t getting us anywhere, create divisions among people and groups that should be working together, and, says the IPCC, won’t have much near-term leverage on atmospheric carbon dioxide.
What if, and this is a big “what if,” rather than wringing our hands over technology and politics, we looked to biology? And rather than flinging ourselves at the inexorable incline of the Keeling Curve, we tapped into the ongoing work of the biosphere, the carbon cycle? By burning fossil fuels, we’re basically short-circuiting the carbon cycle by using concentrated stores of energy created by photosynthesis long ago. What if we could work with natural processes, increasing photosynthesis and slowing down the oxidation of soil organic matter?
Peter likes a quote from Dwight David Eisenhower: “If a problem cannot be solved, enlarge it.” He relates this to our carbon problem: “We have to get beyond the question of pure climate and ask what makes the earth tick. And the answer is, the carbon cycle.”
Now that you’ve humored me through the last several paragraphs, here’s the bumper sticker equivalent: oxidize less, photosynthesize more. Feel free to stick it on your (yes, I know, carbon-dioxide spewing) car.
Bringing our story back to the visit to St. Albans, I return to the bus the next morning, carrying a round of pastries from the Cosmic Cafe. I pass up the monster, skeleton, and pumpkin cupcakes, each under a colorful solid inch of frosting. (This is one town that takes Halloween seriously.) Before the last turn in the road I see a group of brown cows, shades spanning from tan to near black. These are among the cattle that Abe moves from pasture to pasture grazing according to a dynamic plan, four-legged tools for boosting carbon in area soils.
Peter is organizing his traveling bag. He’s off to Saskatchewan to teach workshops and set up some more baseline plots. Abe’s driving him to the airport in Montreal, about an hour and a half away. After Canada, Peter’s plan is to travel south ahead of the bad weather, with scheduled stops in Massachusetts, southern Vermont, Pennsylvania, Maryland, Virginia, and North Carolina and on through Texas and the Southwest before making his way back to Enterprise. “The bus is not a place for cold weather,” he says.
Abe gets milk from the mini fridge, wary of the ceiling as he maneuvers. Peter smiles. “Of course I checked the height before I bought this bus,” he says. “My son is six feet and it doesn’t work for him.”
I ask Peter to reflect on his journey so far. “I’m 210 days in, and nothing too bad has happened,” he says. “I’ve had a number of visits from the police, just checking me out. Twice in Iowa, and once I was just about to cross the Mississippi into Illinois. I was camped at an information center. A cop came by and checked my ID, which interrupted my phone conversation.
“It’s been my intention to go slow, get to know some people and see some country. I’m a pretty experienced traveler—I’ve done thousands of miles on horses and mules. I saw a bunch of innovative farmer-grazers working toward soil health in a dedicated fashion. That was encouraging. But it was dismaying to drive through three or four states and see nothing but corn and soybeans.” Large industrial farms break the heart of people like Peter who care about soil carbon. Generally after harvest the land stands uncovered and the carbon in the soil oxidizes.
“Sometimes I think what I’m doing is crazy,” he admits when I ask. Yet he continues on for the opportunity to talk to people about the intimate connection between the soil and the sky, and the potential for healing this represents. “The opportunity we have to enhance the carbon cycle is a human opportunity, not a technological opportunity,” he says. “It’s easy to get sidelined by technology, but it’s about people: our beliefs, assumptions, and what we think is possible. Most of what we hear about carbon and the global carbon cycle is threatening and negative. It’s a bad situation and we don’t seem to have much power or leverage over it. All our environmental and economic concerns depend on the ways carbon and water move—and water follows carbon both into the air and into the soil. We need to understand that human decisions have an enormous influence on the way these cycles function.”
In order to get this point across, he has a new prop, which I later see on his visit to Bennington: a protest-style placard that reads: OCCUPY THE CARBON CYCLE. This is, after all, the autumn of 2011, the heyday of Occupy.
I see that Abe Collins is looking at his watch. But he isn’t urging me to leave just yet. “Every major advance in human economic and social life has been tapping a new carbon source,” he says. “Think of farming, oxidizing organic matter to release nutrients to grow crops, think of forestry—for timber and charcoal, think of coal and then oil. We’ve tapped the really rich energy sources. Now we’re at a point where we’ve tapped the soil. It’s tapped out. We’ve lost an estimated 50 to 80 percent carbon in our soils over the last 150 years. We’ve got to get people to make the fundamental link between our economic and ecological cycles.” And the importance of recharging the soil, to keep the ground covered and get a broader range of plants growing again. At least on that score, he believes he knows what needs to be done: “Let the animals and nature do more of the work.”
Cows, Methane, and All That Hot Air
If I mention that I’m writing a book that deals with climate change and anyone catches the word cows in the title, the first reaction is usually, “Oh, you mean it’s about how cows are causing global warming!” For some reason this myth has caught the public imagination. Let’s get this clear: The burps and farts of bovine animals are not to blame for climate change.
First, to understand how the rumor got started:
1. Cattle, like all ruminants, emit methane as part of their unique digestive process (from the front end, actually). According to the EPA, ruminant live-stock annually generate about eighty million metric tons of methane, which is approximately 28 percent of the global methane emissions attributed to human-derived activity.
2. Methane (CH4) is a greenhouse gas. In terms of heat trapping, it’s about twenty-five times more potent than carbon dioxide.
3. Therefore, we should cork those cows and then we won’t have such a problem with greenhouse gases.
This makes some degree of sense, right? At least until we look at cows-and-methane within a biological context:
1. That methane-is-twenty-five-times-more-potent figure is widely reported and accepted by many as fact. However, David Mason-Jones, an Australian journalist and author of Should Meat Be on the Menu?, says this metric “simply does not compare apples with apples.” CO2 and CH4 have different weights, with a carbon dioxide molecule nearly three times as heavy as a methane molecule. Rather than comparing the global warming potential of a molecule of carbon dioxide with a molecule of methane, the twenty-five number expresses the activity of a kilogram of methane versus a kilogram of carbon dioxide.2
Plus, methane in the atmosphere breaks down much more quickly than carbon dioxide; in the presence of oxygen CH4 turns into CO2 and H2O, or water.
2. As Mason-Jones points out, the methane cycle functions as a subsystem within the larger carbon cycle of growth, digestion, and decay: “The production of methane in a landscape should be recognized as an inevitable consequence of plant growth because, when plants grow, they inevitably get eaten by something . . . Methane is one of the biological consequences of this and will occur whether there are farm animals in the landscape or not.”
3. It’s not the cattle themselves that are making the methane. The gas is a by-product of enteric fermentation, the type of digestion ruminants perform, and released by bacterial symbionts in a cow’s stomach chambers in the process of breaking down cellulose. Humans can’t eat grass, but cattle, thanks to their microscopic partners, are performing the service of turning inedible grasses into protein that we can eat.
4. There seems to be little correlation between methane levels and the number of ruminants. A joint 2008 report from the FAO (the UN’s Food and Agriculture Organization) and IAEA (International Atomic Energy Agency) noted that since 1999 atmospheric methane concentrations have been stable while the population of ruminants worldwide grew at a rapid rate, raising the question of whether livestock play much of a role in the greenhouse gas situation.
5. The amount of methane cattle generate has a lot to do with how livestock is managed. According to Andrea Malmberg, director of research at the Savory Institute, when cattle are in crowded feedlots (concentrated animal feeding operations, or CAFOs) the manure is handled in liquid form, in lagoons or holding tanks—an ideal scenario for the production of methane. If, however, cattle graze on fields in lowered concentration, the manure becomes fertilizer. She adds: “These are human decisions, not the cows’.”
Biochar and Its Source (Fire)
If you scroll around on the topic of soil carbon, sooner or later you’re bound to bump into biochar. Biochar is charcoal used in an ecological context, primarily as a soil amendment, created by burning plant material (wood and crop residues) under low-oxygen conditions, known as pyrolysis. (It’s also sometimes known as terra preta, or “black soil,” after research in the Amazon showed that indigenous people there applied it to their soil more than a thousand years ago. It is stable, concentrated carbon that, when added to soil, enhances fertility and sequesters carbon. Advocates tout biochar as the answer to climate change. (The Guardian referred to proponents as “charleaders.”) For me, such grand claims triggered the too-good-to-be-true alert. So I contacted Steven Apfelbaum, a world-recognized expert on ecological restoration and the founder and chairman of Applied Ecological Services in Wisconsin. He’s my go-to guy whenever I need a scientific reality check. Here’s what he said:
Biochar is one of the ways nature has stored carbon. In most forest soils, there are chunks of it: coarse fragments of carbonized wood. Lots of it is easily 400 to 1000 years old. You’ll find this in northern forests, Midwest oak savanna systems, Coastal peatlands, the Pacific Northwest, all the way to up the Arctic—carbon stores, stable and protected.
Historically, the primary origin of biochar is wildfires, he said. According to Joel S. Levine, a senior research scientist at NASA, about 30 percent of global annual carbon dioxide emissions can be attributed to biomass burning.
Apfelbaum continues:
Today most wildfires—perhaps 90 percent—are human-ignited, and many occur under extreme conditions. Uncontrolled, catastrophic wildfires lead to major erosion, opportunistic species on scarred land, and greenhouse gas emissions—not to mention any other losses involved. However, there are also prescribed fires that can be administered as part of restorative management. One byproduct of a controlled fire is biochar. Another is greater land productivity. Carbon is sequestered in the soil and you have a more open, less competitive, environment conducive to plant growth.
Many forests have way more trees than the land can support. The soil is subject to erosion, and any biochar there is not stable. As the ecosystem deteriorates the soil carbon and biochar oxidize, combining with atmospheric oxygen to form CO2. Controlled burns can restore soil to stable condition and stimulate regrowth of grass, sedges, and other plants. The kind of burning I’m talking about [is] light ground fires to trim overgrown tree canopies that could otherwise be prone to wildfire. With prescribed burning, you slowly morph the ecosystem back to a healthy condition—rather than administer the near-death experience of an all-out wildfire.
I see prescribed burning as a low-hanging fruit for the biochar industry. That and using waste wood and other cellulose material to create carbonized products for agriculture. We should be using nature as a role model and look at conditions that have led to this and learn from that rather than fabricating products.
Right now, says Apfelbaum, biochar production is primarily experimental and small-scale, though he believes it holds promise.
One sometimes cited concern about biochar as an industry is that agricultural lands, particularly in the third world, might be turned into charcoal plantations, diverting millions of acres from food production and creating a new breed of monoculture. Plus, can we assume that commercial biochar will have the same soil-enhancing effects as that formed in nature? At least one study casts doubt on this. Then there’s a question of whether the production of biochar could generate more emissions than assumed, including the black soot that causes respiratory disease. Sounds like we should tread slowly with biochar. After all, it is playing with fire.