I try, very consciously, not to begin too many sentences with, “I read in the New York Times that…” It’s a struggle (and frankly, my fallback—“I heard on NPR that…”—isn’t really much better). It’s not my only source of information in the world, but it is usually the one I check first in the morning. A few days ago, two headlines stood out to me. One promised to show me any number of ways to reduce my carbon footprint, the other asked if dirt could save the Earth. I read both with interest. In “Can Dirt Save the Earth?”, I learned about farmers in California experimenting with ways to make their land store more carbon, drawing it down from the atmosphere. “How to Reduce Your Carbon Foot Print” told me to fly less, reduce my meat consumption, and buy LED light bulbs. But nowhere did it explain to me that, like the California farmers, my home landscape could help me reduce that footprint by absorbing more of the carbon my lifestyle emits. Amid all the suggestions for ways to reduce my carbon footprint, discussion of how to suck up more of what’s already in the atmosphere was nonexistent, despite the fact that another article in the same paper had already clued me in.
The fact that plants take in carbon dioxide and use it to make important things like oxygen, water, and sugar is usually old news for people. The sugar serves as the plant’s food—they are autotrophs, meaning they never need the phone number for their local Thai place on a busy Tuesday night when no one has the time or energy to cook. Photosynthesis makes sugars in the plant’s leaves, which then move down into the roots. Some of the sugar is used to keep the plant alive, some is stored, and some actually leaves the roots and moves into the soil. Why take your hard-earned sugars and kick them out into the dark, damp earth around you? Because plants have worked out an evolutionary deal with mycorrhizal fungi and bacteria—carbon in exchange for other nutrients, everyone wins. The fungi then use the sugars to create a protein called glomulin that is a key part of healthy soil.
If you’re a gardener and you’ve ever dug into dark, crumbly soil, you’ve touched glomulin. That crumbly dirt has a formal name: humus (NOT hummus. One “m”. Critical distinction). And humus is where it’s at, if you’re a gardener or a microscopic soil organism or a bit of carbon that’s been pulled out of the air. Humus can store significant quantities of carbon, which is why some farmers in California are experimenting with ways to increase the amount of it on their land, and why they think dirt might save us from climate change. If there was more healthy, humus-rich soil in the world, it could store more of the carbon we so frequently emit, despite all those LED light bulbs. Those farmers are mostly looking at spreading tons of compost onto their lands to increase healthy plant communities above the soil and healthy microbial communities below it.
These farmers manage hundreds of acres, while I am responsible for a mere 0.2 acre lot in suburbia that is largely occupied by a house. But lawns, both in front of private homes and those in public and commercial spaces, take up 40 million acres of the United States alone. What if those 40 million acres were managed in such a way that they could store more carbon? Homeowners can replicate many of the same practices as these farmers and scientists. Apply compost, plant more deep-rooted herbaceous plants as well as trees and shrubs, minimize soil disturbances to the extent possible. These practices, taken together and widely adopted, could help our home landscapes transition from places that emit carbon due to mowing, fertilizing, and tilling into places that absorb and store carbon deep in the earth. And while no one would argue that America’s lawns can store enough excess carbon to fend off all of the impacts of climate change, we are in an “all hands on deck” moment. Every strategy counts, every tool has a place in the tool box. Ride a bike more often, eat lower on the food chain, and change your landscape practices to encourage carbon sequestration.