The Soil Solution to Climate Change

May 16, 2019

The Nation:

Ninety people are gathered along a trench—maybe 20 feet long, five feet deep, and three feet wide—in the Montana prairie. It’s an overcast spring day, with a cool breeze stirring the grass. Children clamber around the edges of the trench while the adults crouch or stand, listening to a woman pacing at the bottom, pointing out roots and different layers of exposed earth, talking about how the soil can save us from a climate catastrophe. The speaker is Nicole Masters, an agroecologist from New Zealand, conducting a workshop on soil health for this audience of ranchers, farmers, and conservationists.
“Even if we stopped burning fossil fuels tonight,” Masters says, “we’d wake up tomorrow and still have 400 parts per million of carbon dioxide in our atmosphere.”
That figure has risen from approximately 280 parts per million in 1780, when the Industrial Revolution kicked in and burning coal became the way to power factories and trains. Over time, the use of such fossil fuels has triggered a greenhouse effect, trapping heat in our atmosphere and raising Earth’s surface temperatures to a level not experienced for some 150,000 years. Masters’s message is that while replacing fossil fuels with clean energy from the sun, wind, flowing water, and the planet’s own heat is certainly necessary, it is not enough. To stop runaway global warming, tame the fierce extremes of weather we are now experiencing, slow down and eventually reverse the melting of icecaps and glaciers, rescue drowning islands, and revive dying coral reefs, we must also find a way to remove excess carbon from the atmosphere and sequester it in the soil.

How do we get greenhouse gases out of the air?” Masters asks the people at this workshop.
Our host, a rancher named Steve Charter, answers, “Photosynthesis.”
“Right,” she says. Plants not only take in carbon dioxide but also create ground cover—and this gets carbon back in the soil.
“You are solar ranching,” Masters continues as she writes the chemical formula for photosynthesis on a whiteboard: sunlight + 6CO2 + 6H2O (water) = C6 H12O6 (basic sugar) + 6O2 (atmospheric oxygen). “Everything that grows here starts with sugar. Soil microbes eat sugar.” And feeding these soil microbes builds soil and sequesters atmospheric carbon in the ground “at a rate previously thought impossible.”

The message of agroecologists like Masters is taking root around the planet with the rapid growth of regenerative agriculture: creating the conditions for plants to retain as much carbon in the ground as possible. “Carbon farming” is one term for this effort, and we can add “carbon ranching” and “carbon gardening” because, to succeed, this practice must occur on many levels.
The key insight of regenerative agriculture is not new. Humans have long recognized that the soil is alive, teeming with diverse, interacting creatures: bacteria, fungi, algae, mites, nematodes, earthworms, ants, spiders, the roots of plants. Soil flourishes in that narrow zone between rock and air, transforming mineral to vegetable, inanimate to animate.
But for far too long—at least 8,000 years—we human beings have treated the soil badly in many parts of the world: setting fires to drive wild animals or to clear land; overgrazing grasslands with domestic animals; plowing, planting, and harvesting crops, then leaving the ground denuded and vulnerable to wind and water erosion.
Central Australia, the Sahara, and various deserts in Asia and the Americas were once semiarid grasslands. Old-growth forests have dwindled and, in many places, disappeared. Over the Great Plains of North America, vast herds of bison and elk roamed, spurred by predators (primarily wolves and, after we arrived, human beings) to bunch up in herds for self-defense, then move on, leaving urine, saliva, and dung to revitalize the land. In some places, the topsoil was six feet deep. Within the last century, however, this topsoil has been exhausted by farmers deep-plowing and planting grains, primarily corn and, more recently, soybeans.

PRI – Living on Earth:

While discussions about climate change usually center on reducing greenhouse gas emissions, Eric Toensmeier is focused on the other side of the equation: how to capture the carbon dioxide that’s already in the atmosphere. 
And he thinks the answer might be in his backyard garden.
At one-tenth of an acre, Toensmeier’s garden in Holyoke, Massachusetts, is not a large space. But with 300 varieties of perennial crops, his experiments on growing them in different configurations — to increase nutrients, slow erosion, provide cover from the elements and capture carbon — make it a valuable laboratory.

The techniques he has refined are the subject of his new book, “The Carbon Farming Solution.” Put simply, the practice of “carbon farming” is agriculture that captures carbon in the trees, plants and biomass of farmed crops, with the goal of curbing global warming.
In warm parts of the world, trapping carbon in crops is much easier, Toensmeier said. Some studies have even found tropical gardens can hold more carbon than nearby forests.
Without the advantage of tropical climates, farmers have to think differently if they want to sequester more carbon. Currently, large-scale commercial agriculture mostly grows commodity crops, like corn and soybeans, which are planted annually.
Toensmeier said this approach produces a lot of food in a relatively small space, which minimizes deforestation. But at the same time, it relies on chemicals that can be harmful to the environment. It also fails to capture additional carbon.
Toensmeier admits it is tough to persuade farmers they should spend money on their operations to help slow climate change. When it comes to global warming, he said, “In the United States a lot of our farmers don’t think it’s a real thing at all.”
“But, when you talk about the particular practices” that can help address the problem, he said, “many of [the farmers] are very excited about them and want to do them.”
And how much of a difference can be made by changing the way we farm and garden?
“We ran numbers at one point on our backyard,” Toensmeier said, and estimated the garden “offsets the emissions of one American adult in one year.”
“If all of us did this in our gardens it wouldn’t be enough to do the trick,” he said, “but it would be a huge contribution.”
For gardeners and farmers interested in carbon farming, Toensmeier recommends growing more perennial crops and mulching instead of tilling. He pointed out that by growing your own food, you are already cutting emissions — by reducing the distance it travels from the soil to your plate.

Very nice, long article here in New York Times magazine – well worth a look.

New York Times Magazine:

Dozens of land-management practices are thought to achieve this feat. Planting or restoring forests, for one: Trees lock up carbon in woody material. Another is adding biochar, a charcoal made from heated organic material, directly to soil. Or restoring certain wetlands that have an immense capacity to hold carbon. (Coal beds are the fossilized remains of ancient marshes and peatlands.)
More than one-third of earth’s ice-free surface is devoted to agriculture, meaning that much of it is already managed intensively. Carbon farming’s fundamental conceit is that if we change how we treat this land, we could turn huge areas of the earth’s surface into a carbon sponge. Instead of relying solely on technology to remove greenhouse gases from the air, we could harness an ancient and natural process, photosynthesis, to pump carbon into what’s called the pedosphere, the thin skin of living soil at the earth’s surface. If adopted widely enough, such practices could, in theory, begin to remove billions of tons of carbon dioxide from the atmosphere, nudging us toward a less perilous climate trajectory than our current one.
In a 2016 paper, Pete Smith, a soil scientist at the University of Aberdeen in Scotland, and the influential climate scientist James Hansen argued that land-management practices are one of the few affordable options available today for drawing down carbon. “What’s surprising to me is that we’ve not done it sooner,” says Smith, who is also a lead author on a recent U.N. report that explores carbon-dioxide-removal technologies. “This has the potential to make a huge difference.” Otherwise, Hansen told me, we’re leaving the problem to our grandchildren. “That assumption that somehow young people, and people later this century, are going to figure out how to suck it out of the air — that’s a pretty big burden to place on them,” he said.
The I.P.C.C. is preparing a special report on climate change and land use, to be finalized in 2019, that will consider in greater detail the potential of sequestering carbon in soil. But for now the biggest international effort to promote carbon farming is a French-led initiative called “four per 1,000.” The proposal aims to increase the amount of carbon in the soil of crop- and rangelands by 0.4 percent per year through a variety of agricultural and forestry practices. These include agroforestry (growing trees and crops together increases carbon retention), no-till agriculture (plowing causes erosion and carbon loss) and keeping farmland covered (bare dirt bleeds carbon). Doing so, the French argue, could completely halt the buildup of atmospheric carbon dioxide.
Few experts I spoke to think the impact would be quite that grand; Pete Smith, for example, estimates that soil could, at the most, store just 13 percent of annual carbon-dioxide emissions at current levels. “I appreciate that everyone wants to save the planet,” he told me, “but we shouldn’t fool ourselves that this is all we need to do.” Even so, the four-per-1,000 goal highlights how a relatively small annual increase in soil carbon could, on a large-enough scale, have a substantial impact. Increasing soil carbon could yield other benefits, too: Improvements in soil fertility, water retention and greater crop resilience would help agriculture adapt to a warming world. More soil carbon would also reduce the amount of fertilizer needed, decreasing emissions of the powerful greenhouse gas nitrous oxide, a byproduct of excess nitrogen fertilization. It would be profoundly appropriate if agriculture, whose modern practices have themselves contributed to climate change, could become part of its solution. Farming, responsible for the birth of civilization, could now help save it.


17 Responses to “The Soil Solution to Climate Change”

  1. rsmurf Says:

    I have well over 200 small, medium and large trees on my property up from maybe 1/2 that 30 years ago, we may all need to let those resource hungry lawns grow up into trees! Although here in Dallas we are loosing so many trees to terraforming it’s really sickening!

    • Terry Donte Says:

      Trees are a pretty short term storage of CO2. In the tropics the only actual storage is in the living trees as the soil bacteria break down the dead leaves and branches in nothing flat. In the amazon where I have been , there is essentially zero plant material in the soil below about 1/2 inch. In the temperate zones the deep loamy soil ideal for growing is a store of CO2 but that store is only a few hundred years old at most, in the arctic the store is larger but not much as the soil remains frozen below a few feet so the amount of material stored there is pretty shallow. The oceans are a much larger store as the CO2 gets taken out to form plankton shells and when they die the shells drift to the bottom to form a lot of the rocks we live on when they get pushed up to the surface.

      • rsmurf Says:

        We can grow trees very easily, and should. Plus we need to stop chopping them down. This is a fix we need to do. Everything has its pluses and minuses we need to do EVERYTHING WE CAN.

  2. Terry Donte Says:

    The increase in humans is the problem, not CO2. Per NASA research the world is greener due to increased CO2, the estimate is 8 percent which means 415 people are alive who otherwise would be dead from starvation. Taking care of the soil is good sense. Having been in South America, Africa, Asia, a whole lot of people are not taking care of the soil which is really going to hurt food production and already is. A whole lot of places, the middle east for example, eat more than they produce, Our farmers and others make up the difference.

    • rhymeswithgoalie Says:

      Per NASA research the world is greener due to increased CO2, the estimate is 8 percent which means 415 people are alive who otherwise would be dead from starvation.

      NASA citation definitely needed for context.

      For both agriculture and natural foliage, the stress from increased heat, pests, and/or reduced soil moisture far outweighs the benefits of increased CO2:

      • J4Zonian Says:

        Well, it is bad insects eat more plants at the higher CO2 levels expected by 2050. Fortunately, we’re taking care of that and there won’t be any insects by 2050.

    • sailrick Says:

      The main problem is burning fossil fuels, by which we release into the atmosphere and oceans, carbon that nature locked out of the fast carbon cycle for tens of millions and hundreds of millions of years. Now we are putting it all in the fast carbon cycle in just a few centuries. In a blink of an eye of geological time scales. 65% of our CO2 emissions are from burning fossil fuels. And they don’t belong in the fast or active carbon cycle.

      The Carbon Cycle

      “Without human interference, the carbon in fossil fuels would leak slowly into the atmosphere through volcanic activity over millions of years in the slow carbon cycle. By burning coal, oil, and natural gas, we accelerate the process, releasing vast amounts of carbon (carbon that took millions of years to accumulate) into the atmosphere every year. By doing so, we move the carbon from the slow cycle to the fast cycle. In 2009, humans released about 8.4 billion tons of carbon into the atmosphere by burning fossil fuel.”

      • sailrick Says:

        All the components of the fast cabon cycle give and take carbon – soils, oceans, atmosphere and living things.

        Not so with fossil fuels – a one way street, all give and not take back

  3. sailrick Says:

    My kingdom for a text editor

  4. Gingerbaker Says:

    ” “Everything that grows here starts with sugar. Soil microbes eat sugar.” And feeding these soil microbes builds soil and sequesters atmospheric carbon in the ground “at a rate previously thought impossible.””

    What the heck is she talking about here?

    Digestion of sugar produces carbon dioxide. This is basic biochemistry. The digestion of sugar is the *exact opposite* of how to build up carbon in the soil.

    Building up carbon in soil is done by increasing the cellulose concentration in the soil. While the breakdown of cellulose is pretty fast, soil could represent a gigantic increased carbon sink. But only with a huge global soil program. Not likely to happen.

    We could accomplish many year’s worth of such a global program in one fell swoop by killing off the termites in the newly discovered UK-sized colony in Brazil.

    And you gotta wonder if we could hack the genome of a universal prolific weed to modify its cellulose into a form that resisted microbial digestion.

    • redskylite Says:

      I remember from my industrious home brewing days, those hardworking yeast cells used to eat the sugars giving ethyl alcohol and CO2.

      “Termites add to the rising methane levels. . . Undark reports

      The Methane Detectives: On the Trail of a Global Warming Mystery
      The amount of heat-trapping methane in the atmosphere seemed to be leveling off when, in 2007, it began rising again quickly. Nobody yet knows why.

      Humans are directly responsible for about 60 percent of global emissions of methane. It seeps from rotting food waste in landfills, from anaerobic lagoons of pig manure, from rice paddies and exposed coal seams. Livestock belch it out as a byproduct of their digestion. It streams out of the vast metallic exoskeleton of oil and gas wells, pumping stations, pipelines, and refineries that entwine the globe.

      The balance comes from natural sources — wetlands, rivers and lakes, wildfires, termites, geological seeps, thawing permafrost. ”

    • dumboldguy Says:

      “Digestion of sugar produces carbon dioxide. This is basic biochemistry. The digestion of sugar is the *exact opposite* of how to build up carbon in the soil”, says GB, who obviously needs a refresher course in biochemistry.

      Masters perhaps oversimplified (or the reporter did it for her), but GB does so to the point of confusion. The “sugar” created through photosynthesis is not just “burned” but is the basic building block for the long chain polysaccharides such as cellulose, starch, and lignin. Look it up, GB.

      • Gingerbaker Says:

        Digested sugar doth not cellulose make, DOG. Drink your coffee before you comment.

        • dumboldguy Says:

          She was talking to members of the public and children, not a bunch of scientists, GB.
          Did I not say that it was oversimplified? Did I not use (“) marks to indicate?

          Do you not understand that the building of those compounds I mentioned locks carbon atoms into thousand-atom-long chain molecules and releases the OXYGEN we are so indebted to plants for?

          Take a course in biochemistry and STOP drinking your Vermont Maple Syrup Vodka before you waste our time with futile semantic exercises.

  5. redskylite Says:

    Its good that farmers and ranch owners are attending talks on improving the lands “carbon sink” abilities,and I’m sure agricultural academia stress on it too. We’ve got to get back in balance somehow, and avoid those madcap geoengineering ideas.

    Stop soil erosion now or face starvation soon, scientists warn

    “The world’s food production is in jeopardy because the fertile layer of soil that people depend on to plant crops is being eroded by human activities, scientists said on Wednesday.

    Climate change is likely to make it worse even as demand from a grown population is soaring, they said.

    Soil erosion happens naturally, but intensive agriculture, deforestation, mining and urban sprawl accelerate it and can reduce crop yields by up to 50%, according to the United Nations’ Food and Agriculture Organization (FAO).

    FAO also said the equivalent of a soccer pitch of soil is eroded every five seconds, and the planet is on a path that could lead to the degradation of more than 90% of all the Earth’s soils by 2050.

    “We’re approaching a critical point at which we need to start acting on soil erosion or we are not going to be able to feed ourselves in the future,” Lindsay Stringer, professor at England’s University of Leeds, said.”

    • redskylite Says:

      From: Microbial ecologist Janet K. Jansson
      Pacific Northwest National Laboratory

      As climate changes, so does life in the planet’s soils

      I’m concerned about how climate change will affect these highly productive regions of the world, especially with increasing droughts.

      Looking at the metaphenome, and the influence of the soil drying on the metagenome, we have found that the microbial community starts to shift its metabolism toward the production of metabolites that help them survive dryness, like sugars and different kinds of osmolites, molecules that help keep the cells from bursting when the soil gets dry.

      The thing that really impresses me is that we can now look at a whole community and dissect what the community is doing in response to drought.

      We have to conserve our soils. They are alive — they carry billions and billions of microorganisms in a single gram. So, this is a living resource that we have to protect from being eroded and degraded.

  6. dumboldguy Says:

    The “soil solution” should properly be titled “The Soil Distraction”. Good ideas all, but soil is being eroded and destroyed at a far greater rate than any of these “solutions” can be implemented. As long as we allow ourselves to be distracted from the FACT that we are NOT cutting back on fossil fuel use rapidly enough, the brightsided among us will say “Oh, there’s time yet—we can fix it—not to worry”. Sad.

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