Understanding How Soil May Save Our Planet: A Carbon Farming Breakdown

In 1937, amid the Dust Bowl crisis, Franklin D. Roosevelt delivered a speech with the following quotation: “A nation that destroys its soil destroys itself.” A 2012 article in Time written by the World Economic Forum pulls FDR’s line forward with an ominous portent for our global future: at the current pace of degradation, the world has roughly 60 years of topsoil left. However, with each problem comes opportunity. A relatively new movement embracing regenerative farming techniques is not only rebuilding the living soil beneath our feet, but might also provide a cost-effective answer to the dire planetary outlook associated with climate change.

WHY SOIL IS IMPORTANT

One handful of soil contains more microorganisms than people on the planet. These microorganisms rely on the basic building block of life: carbon. The earth’s soil actually contains more carbon than the atmosphere and all plant and animal life combined, about 2,500 gigatons. Modern industrial farming degrades our soil, leaching out the carbon and causes erosion. As a result it takes more and more water to produce less food, emitting more carbon into the atmosphere. Currently the earth’s soil removes about 25 percent of the world’s fossil fuel emissions each year, but as soil continues to degrade, the amount of carbon dioxide in our air increases.

HOW IT WORKS

Without getting too technical, plants suck CO₂, water, and sunlight from the air to create a simple sugar liquid during photosynthesis. This sugary drink is then discharged into the soil, where the carbon becomes sequestered. This process also increases biodiversity above and below the earth’s surface, while helping water retention. From a food perspective, carbon-rich soil is great for growing crops and pasture-raising animals, and reduces the need for any chemical fortification of overused farmland. From an environmental perspective, it’s critical to keeping that carbon from heating our planet.

WHERE WE STAND WITH CARBON

Converting the earth’s soil to rangelands and croplands has resulted in a loss of around 70 percent of its once-contained carbon. If reducing the rate at which we burn fossil fuels is a preventive approach to combating the release of carbon into the air, repairing the soil so that it can sequester carbon can be seen as a corrective approach. In other words, we need to prevent carbon from polluting the air, but we also need to do something with the carbon problem we already have. Rattan Lai, Professor of Soil Science at Ohio State University, uses a banking analogy: “You cannot withdraw more than you put in…Organic matter, or soil carbon, is the reserve of nutrients in the soil. When you do not replace what you have harvested, then the organic matter content is decomposed and nutrients are released.”

TO KNOW THE NATURE OF SOIL

A new movement aims to balance our soil bank account. Instead of mining the soil, these carbon farmers and regenerative agriculturists are rebuilding the health and biodiversity of soil through specific grazing and farming practices. A 2017 study published in Science magazine suggests that farmers that partner with nature are on the right track, stating soil could contain enough carbon to offset the annual output of the entire United States and that it could retain its carbon for almost half a century. Further findings show carbon sequestration has the potential to offset fossil fuel emissions by 0.4 to 1.2 gigatons of carbon per year, or 5 to 15 percent of the global fossil-fuel emissions.

RESTORATIVE AGRICULTURE AT A GLANCE

Basic practices of restorative agriculture:

1. Reduce or eliminate tillage: Tilling breaks up the land which releases the carbon it once stored, makes it difficult to retain water, and destroys the living microbial communities beneath which sustain it.
2. Cover to fertilize: Instead of using chemicals to create growing conditions, applying cover crops, manure, compost, and regularly rotating crops to promote nutrients in the soil reduces nitrogen leaching and wind and water erosion.
3. Promote biodiversity: Extending beyond crop rotation. Fungi, algae, earthworms, ants and just about any other critter you can imagine fill gaps in the food web, creating healthier soil and promoting resilience in the ecosystem.
4. Pasture animals: While industrial-scale concentrated animal feeding operations (CAFOs) destroy land and pollute water, well-managed grazing practices, such as rotational or Management Intensive Grazing, where animals graze a single paddock while others recover, and then are rotated quickly to another paddock, increase the insect and plant biodiversity, soil fertility, and carbon sequestration.

SOIL IS THE NEXT NEW THING

To bolster restorative environmental efforts, San Francisco, California and Cambridge, Massachusetts have enacted composting initiatives to reduce food waste and water runoff. According to The Marin Carbon Project, applying compost just once could increase the soil’s carbon content continually. Even General Mills, one of the world’s largest food producers, recently announced a plan to advance regenerative agriculture practices on one million acres of farmland by 2030 to build better soil, combat carbon-based emissions, and reduce water consumption.

There are many exciting plans out there to combat climate change and mitigate the damage to the environment caused by increased concentrations of negative greenhouse gases: ideas such as giant air purifiers and fertilizing the ocean with iron to promote carbon-capturing algae. But perhaps none are as scalable or affordable as improving soil through better farming techniques. Indeed, “despite all our achievements we owe our existence to a six-inch layer of topsoil and the fact that it rains.”