After Geoengineering

by Holly Jean Buck

  “I used to present to people about regenerative … and I had a constant feeling that people weren’t really understanding what I was saying.” He explains that it’s not that we can’t understand what “regenerative” means. It’s that we’ve lumped it into our preexisting container of things that are “environmental.” “And unfortunately our preexisting container … to put it bluntly, [is] not as epic as the regenerative container.” Our preexisting container is the “sustainable” container: the impulse to “do less harm, stop messing up the earth, stop taking too much.” The recycling symbol, with the arrows forming a circle, is emblematic of this sustainable container. “That recycling symbol is very easy to recognize. And most people will say, ‘Yeah. That’s where I’m at.’”

  We need to think outside the circle, Makepeace insists, and expand our thinking beyond mere sustainability. To be “sustainable” is more like rearranging the deck chairs on the Titanic. It doesn’t do enough to move us beyond an extractive, degenerate relationship with nature. A regenerative approach is thus not about doing less harm, but about healing and restoration. His way of explaining it is with a regenerative spiral. Regeneration goes beyond just letting nature recuperate; it’s about actively working to increase flourishing.

  “Carbon farming” is another term that’s erupted into the sustainable food movement, and it has similar aims as regenerative agriculture, though the term is narrower and more specifically focused upon storing carbon in agroecosystems. Journalist Michael Pollan called carbon farming agriculture’s secret weapon; environmentalist Paul Hawken called it “the foundation of the future of civilization.”4 Carbon farming advocates emphasize the role of agriculture in contributing to climate change. Conventional agriculture is presently a massive source of emissions, with land use change contributing 25 percent of total anthropogenic greenhouse gas emissions (10 to 14 percent from agriculture; 12 to 17 percent from land cover change).5 An increase in soil carbon is accomplished in these key ways: (1) switching to low-till or no-till practices, (2) using cover crops and leaving crop residues to decay, and (3) using species or varieties with greater root mass. Double-cropping systems, where a second crop is grown after a food or feed crop, keep more carbon in the soil, as well. Much attention has also focused on multistrata agroforestry systems, including edible forests or food forests, and silvopasture, which involves grazing animals below trees.

  Regenerative grazing is another version of regenerative agriculture. The idea is that grazing animals, such as cattle, are managed to mimic how animals grazed on the grasslands in pastoralist societies. They eat everything in one area as a herd, till the soil with their hooves, and then move on to another area, allowing the first to regrow. The practice is promoted by Allan Savory, a biologist from Zimbabwe who heads the for-profit Savory Institute. Savory’s TED talk, “How To Green the World’s Deserts and Reverse Climate Change,” made its debut in 2013 and is on its way to 3 million YouTube views. Yet regenerative grazing has faced skepticism. As one critique in a peer-reviewed journal stated, “The false sense of hope created by his promises, expressly regarding some of the most desperate communities, are especially troubling. Scientific evidence unmistakably demonstrates the inability of Mr Savory’s grazing method to reverse rangeland degradation or climate change, and it strongly suggests that it might actually accelerate these processes.” The scientists noted that rangelands are weak carbon sinks because plant production is water limited, and that the ecological benefits of “hoof action” to rangeland restoration were overstated.6 But Savory’s method has scores of passionate advocates. They believe that mainstream science is too reductionist to see the potential. He’s become a folk hero, and something of a counterpoint to modern, corporate-sponsored science. Geographer Rebecca Lave has described his work as an example of “free-range science”: “low-budget, informal, strongly regional, and without the trappings of professionalized laboratories and tools.” In this form of knowledge production, she writes, scientific authority stems from market take-up rather than exclusively from academic prestige or peer review.7

  “Allan Savory goes without shoes to pick up subliminal information about the land that he walks,” report L. Hunter Lovins and colleagues in A Finer Future: Creating an Economy in Service to Life (2018). The authors suggest that regenerative agriculture is “the one real shot we have to counter the climate crisis,” citing several sources who “believe that regenerative agriculture can displace all of the carbon emitted by humans each year and begin rapidly reversing global warming.”8 Indeed, it comes down to a matter of belief; there are a lot of bold claims about what tending the soil can accomplish. This book is not an outlier here; rather, it is one example of an emerging genre. If this potential is genuine, why is it being ignored? Another book, Charles Eisenstein’s Climate: A New Story (2018), explains that regenerative agriculture remains marginal despite its vast potential because it is incompatible with conventional regimes of measurement. Its dynamic and locally tailored practices are incompatible with scientific protocols, meaning that, much like holistic medicine, it can’t be studied.9 The data remains anecdotal, rather than quantitative, he notes, and so it can’t be translated into policy. Ultimately, Eisenstein writes, “we are being invited into a different way of engaging the world … A civilization that sees the world as alive will learn to bring other kinds of information into its choices.”10

  But what does the peer-reviewed science say about the potential of soil carbon sequestration approaches? The principles behind soil carbon sequestration are sound and fairly well understood. To grasp its potential, we have to understand the depleted state of soils today. Soils are vast reservoirs of carbon: they hold three times the amount of CO2 currently in the atmosphere, or almost four times the amount held in living matter. But over the last 10,000 years, agriculture and land conversion has decreased soil carbon globally by 840 gigatons, and many cultivated soils have lost 50 to 70 percent of their original organic carbon. Intensive crop cultivation can reduce soil carbon by 25 to 50 percent in just thirty to fifty years.11 The good news is that this can be reversed. The soil carbon sequestration initiative “4 per 1000,” announced at the 2015 United Nations Climate Change Conference in Paris, has the goal of increasing soil concentration 0.4 percent per year, which would increase the carbon sink by about 4.3 gigatons carbon dioxide equivalent (roughly equal to the emissions of a large emitter like the European Union). One policy brief points out that the 4 per 1000 initiative would cost $500 billion per year, which is in the same ballpark as current agricultural subsidies worldwide.12 New technological capacities could also play a role in reaching these goals—for example, designing crops to have root architectures that could store more carbon.13 Scientists at the Salk Institute, one of those La Jolla–based biotech research institutions, are developing an “Ideal Plant” with carbon removal traits that can be switched on either via traditional breeding or via the gene editing technology CRISPR. At the heart of their strategy is the effort to induce plants to produce more of a molecule called suberin, a biopolymer that’s the main component of cork, which could help roots resist decomposition and store more soil carbon.14

  However it is done, removing four gigatons of carbon dioxide a year via agriculture would be ambitious and fantastic. Even then, it’s only a tenth of what we’re currently emitting. Still, every bit helps.

  It’s important to understand, however, that soil carbon accrual rates decrease as stocks reach a new equilibrium.15 Sequestration follows a curve: the new practices sequester a lot of carbon at first, for the first two decades or so, but this diminishes over time toward a new plateau. Soil carbon sequestration is therefore a one-off method of carbon removal. When the potential is used up, this is called “sink saturation.” It’s also reversible, meaning the new practices must be continued to keep the carbon sequestered.16 And so, if negative emission technologies are expected to be needed later in the century—but we started these methods now—the sinks would already be saturated by mid centur
y.17 Calculations of yearly potential elide this fundamental aspect of the soil carbon contribution. On the other hand, regenerative farmers would argue that you actually gain from implementing these practices, and that since the transition costs are up front, there’s no reason why farmers would want to stop them once they’ve made the transition. What’s more, these are no-regrets solutions, as they simultaneously improve soil quality.

  The eventual climate restoration potential may be the wrong place to focus on right now. Kristin Ohlson is a writer whose book The Soil Will Save Us ranges through several farmlands, from North Dakota to Zimbabwe. She deftly addresses this issue of quantifying how much carbon is actually sequestered.18 As she notes, it’s a tough undertaking: there’s not enough research. “There certainly is a problem with ag departments and ag schools being heavily, heavily funded by businesses that have a stake in the status quo, have a stake in the kind of agriculture that uses a lot of chemicals, does a lot of tillage, and requires a lot of equipment and all of that,” she tells me. The soil is a complex system, and it’s hard to pull out one factor and change it, and then compare it to a control.

  “The soil health practitioners see such dramatic changes on their own land because they’re doing a lot of different things. They’re doing cover crops, and they’re doing compost, and they’re doing no-till, and they’re bringing in their animals to eat down the remaining vegetation. They’re doing all these things that build up life in the soil and carbon in the soil, so I think it’s natural that those people would feel very impatient with the slow and reductive pace of university science.” As she says, the soils do become carbon rich. Ohlson points to the benefits to the whole system: reduction in runoff of fertilizer and other chemicals that pollute waterways; decreased air pollution from blowing dust; and increased soil permeability, meaning the system can resist droughts and floods. “There are so many benefits that come with this,” she adds, “that the average person, even if they don’t have a number to hang onto for carbon storage, for carbon sequestration … should still support this shift—which is a paradigm shift in agriculture, because it has so many benefits.”

  This may be a challenge for those of us fixated on empirical data or climate change narrowly defined, but it’s a useful way of looking at reasons for pursuing soil carbon sequestration. Noah Deich, executive director of the nonprofit Carbon180, also emphasizes the importance of moving in the right direction; the need right now is to begin the work, rather than get caught up in extra-precise quantification. “The question might be a question less of what is the ultimate scale potential, but what are the incentives? What are the policy designs? What are the corporate action campaigns? What are the consumer engagement campaigns that can reward producers for managing their land in a way that sequesters carbon on them? That’s the first step … we need to just get started,” he says.

  Biochar

  Over 2,000 years ago, in the Amazon, indigenous people were managing soils to be carbon rich. Deposits of these dark, fertile soils, called terra preta, can still be found today. Terra preta soils have inspired many advocates for biochar, which is essentially carbonized organic material that benefits soils by making them more fertile and helping them retain water. The basic idea is that biomass—crop residues, grass, other plants or trees—is combusted at low temperatures (300 to 600°C) without oxygen. This process (pyrolysis) results in charcoal, which is a form of organic carbon that can endure.

  Permaculturist Albert Bates got turned on to biochar during his travels in the Amazon. Bates is an environmental rights lawyer, a cofounder of the Global Ecovillage Network, and a long-term resident at The Farm, an intentional community in Tennessee. He’s been concerned about runaway climate change since the 1980s, and in 1989 he wrote his first book on the climate crisis. “I’ve been searching for solutions,” he tells me over Skype from Mexico. “I was kind of despairing over everything, until I went to Brazil for a permaculture course … and got to travel into the Amazon and visit with some scientists there, and study the terra preta soils, and bring some back to Tennessee.”

  In their book, Burn: Using Fire to Cool the Earth, Bates and fellow biochar researcher Kathleen Draper describe various ways that biochar can be used to store carbon. They sketch out how we can go from wasting to banking carbon in virtuous cycles they call “carbon cascades.” The authors travel through the world of biochar projects, from a village-scale biorefinery in China to an eco-lodge in the Dominican Republic. One option for carbon removal is what Bates and Draper describe as bioenergy with biochar capture and storage (or BEBCS, in contrast to BECCS). In our conversation, Bates explains to me that there’s more that can be done with biochar besides enriching soils. Biochar can also go into road construction materials, and into aggregates used in cement and concrete. “Turns out that if you elevate the content in concrete with 8 percent to 12 percent biochar, it actually improves the quality of the concrete over what it had been with just sand,” Bates tells me. It can also be used to improve permeability of surfaces, as has been experimented with in Stockholm. “We’ve got roads; we can look at the bitumen in asphalt. We can look at bridges, airports. We can start to think about composites other than steel, concrete and asphalt; we can think about plastics, and the monomers and polymers that go into the plastics. Many of those are enhanced, it turns out, by carbonates. So you can add biochar, pyrolized carbon, into composites, and now you get a stronger polymer.”

  Using biochar in the built environment would make it possible to employ biomass energy without being reliant on forestry or biomass energy crops, because it would be possible to use things that wouldn’t normally go into agricultural soils. “When you start to talk about putting it in cement, putting it in highways, putting it in airports and roads and things like that, bitumen—now you can stand to add in plastics from municipal waste dumps and bio-solids from sewage treatment plants.” Expanding the feedstock possibilities in this way would be a real breakthrough. “You don’t divert from food or from biodiversity services of forests in order to feed your biomass energies,” he tells me. “You can get your energy from pyrolysis from your sewage treatment plants, from your municipal landfills. All of those can go to make energy for you in vast quantities.”

  In Burn, Bates and Draper look at the potential of biochar when one includes sources like municipal waste, landfills, and so on. With biochar in agricultural soils, Bates comments that the drawdown potential would be one to four gigatons of carbon dioxide equivalent (or, similar to that of soil carbon), when emissions are around forty gigatons. “It isn’t enough. We can talk about tree planting, we can talk about seaweed, we can talk about kelp farming … You sum them all together, and you’re lucky if you get to seven or ten or even twelve gigatons of CO2 per year removal.” But if you look at biochars in these new sinks, “concrete airports and buildings, carbon fiber cars, polymers of various kinds, it works out to closer to fifty gigatons.”

  And it could scale very quickly, Bates argues: “Now we can be talking drawdowns … with ten gigatons a year coming out of the atmosphere, you can begin to calculate how many parts per million we can go down. From 410 down to 400 down to 390 down to 380, 370 and so forth. Well, yes and no. There’s some problems with that approach to this. We’ve been adding carbon to the atmosphere for 100 or 200 years. We know that carbon added to the atmosphere makes it warm up; we know how the greenhouse effect works. We don’t know how fast it responds when we start to withdraw carbon. We deprive the atmosphere of photosynthetic carbon: How fast does the temperature respond? How fast does the chemistry of the atmosphere and the oceans respond? We don’t have any data set for the reverse of warming.” So, Bates cautions, we don’t actually have any proof of this. “That stands as a theory. That’s waiting to be tested.”

  There isn’t much peer-reviewed research on applications of biochar in the built environment, and virtually none of the scholarly meetings I attend on negative emissions science or governance discuss it. I ask Bates why it is that a writer
and lawyer, a self-described hippie who lives in an intentional community and crowdfunds his work on Patreon, is the one who’s looking into this. Bates, though, actually seems quite optimistic about the prospect that really good research universities and institutes will come in and up their game. Part of the promise of this idea, Bates points out, is that it flips the problem from just being about carbon to being about waste management. Another benefit is that it wouldn’t require all the injection of carbon that CCS projects entail. “We don’t need to gasify or liquefy carbon and pump it a mile under the earth or a mile down into the ocean, which would be a bad idea for a number of reasons,” he explains. “Instead we can just solidify it into hard-scape and build our cities of the future, roadways and things of the future, that way.” Rethinking our relationship with carbon and our view of waste is a beautiful vision. Their book is filled with frontline journalism documenting the creativity on the carbon frontier, where interesting ideas receive all too little attention from establishment science and policy, and hope blooms in unexpected places like sewage sludge or sidewalks.

  Planting forests

  Planting trees may be the most beloved option for dealing with climate change. There’s a beautiful kindergarten simplicity to the image. Planting a tree is touted as something that every community can do, and communities benefit locally from the psychological and climate benefits of the green space. Reforestation on climate-significant scales, though, is a different beast.

  One government that has been thinking about forest carbon sinks on a nation-state scale is Bhutan, the world’s first carbon-negative country. They manage this feat in part because of an abundance of hydropower, and because the country’s forests suck up more carbon than the nation produces. Bhutan’s constitution, enacted in 2008, mandates that a minimum of 60 percent of the country’s total land area must be forested at all times. It’s not just pure luck of geography, then, that keeps the country carbon negative; it’s also governance. What enables that kind of leadership?