Can Dirt Save the Earth?
Originally posted on nytimes.com
Written by Moises Velasquez-Manoff
Nearly all the carbon that enters the biosphere is captured during photosynthesis, and as it moves through life’s web, every organism takes a cut for its own energy needs, releasing carbon dioxide as exhaust. This circular voyage is the short-term carbon cycle. Carbon farming seeks to interfere with this cycle, slowing the release of carbon back into the atmosphere. The practice is often conceptualized and discussed in terms of storing carbon, but really the idea is to change the flow of carbon so that, for a time at least, the carbon leaving a given ecosystem is less than the carbon entering it.
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.