Soil has many incredible properties, perhaps none moreso than the ability to store a tremendous amount of carbon—soil can hold 2-3 times more carbon than the atmosphere.1 In a charming coincidence, carbon is the key to creating a healthy soil. William Albrecht, the godfather of soil health, wrote in 1953 that soil organic matter (which is primarily carbon) is: “the most neglected and most important chemo-dynamic factor of the soil . . . [it] may be said to be the constitution of the soil.”2
Now, I don’t know what chemo-dynamic factors are, but I do know that soil carbon, soil health, and plant health are all directly related. The more carbon in the soil, the healthier the plants that grow in it, the more nutritious their produce, and in turn the more carbon they are able to add back into the soil. It’s a positive feedback loop.
Ironically, traditional agriculture has had a devastating effect on soil carbon. Through erosion and mismanagement, up to 50% of the earth’s native soil carbon has been lost to the atmosphere.3 The good news is that regenerative practices can add that carbon (and more) back to the soil relatively quickly.
At the 2015 Paris climate conference, the French agriculture minister proposed an initiative called “4 per mille,” which called for adding carbon to the soil at a rate of 0.4% (or four thousandths, hence the French name) per year in all soils across the globe. This rate of carbon sequestration would exactly balance the annual growth in CO2 emissions (about 9 gigatons), buying us time to implement other, more aggressive, climate solutions. Soil has a limit to how much carbon it can store, but 0.4% growth could be sustained for a few decades before the soils became saturated.
The math behind 4 per mille relies on using all the earth’s soils to meet its goal. But every scientific article I’ve read about 4 per mille only considers farmland to be a realistic target for carbon sequestration—ignoring all other soils: backyards, highway medians, forests, soccer fields, etc. I’m all for encouraging farmers to adopt regenerative soil-building techniques. But the problem is that farmland only accounts for 45% of global soils, (41% in the U.S.); therefore focusing on farmland means falling woefully short of 4 per mille’s sequestration goal. And only 1.3% of Americans are farmers, leaving the remaining 98.7% of us to idly watch as the world cooks.
Ecologist Douglas Tallamy, in his case for getting everyday people to take ownership over wildlife conservation, identifies 600 million acres of privately-owned “wasted” land in the United States4 (By comparison, U.S. farmland totals about 900 million acres):
• Exurbia: 333 million acres • Suburbia: 101 million acres • Urban centers: 69 million acres • Rural residential: 50 million acres • Power and pipeline right of ways: 21 million acres • Roadsides: 17 million acres • Railroad right of ways: 3 million acres • Airports: 3 million acres • Golf courses: 2 million acres
Of course, many of those acres are covered by houses and parking lots and gazebos, but that still leaves an awful lot of soil with carbon sequestration potential.
Why is all that soil ignored by the experts? I came up with a few reasons:
Scale
The average farm in the US is 446 acres, whereas the average residential property is about ⅓ of an acre. So each farmer represents over 1300 times more sequestration potential than each non-farmer—a tremendously better bang for the buck in outreach and education.
Consistent Management
Soil can very easily lose its carbon back to the atmosphere, so in order to maintain any gain in soil carbon, management style must be consistent. If a farmer tries new methods that increase soil carbon by 0.4% year by year, and then sells her land to someone who returns to conventional management, all that carbon will quickly be lost to the atmosphere, and we’re back to square one.
But it doesn’t seem that farmland is more likely to be managed consistently than other types of land. Residential properties changed hands at a rate of 1.5-2% per year over the last 10 years.5 Meanwhile, farmland changed hands at 2% per year, and that rate is soon expected to increase to 3-4% as the current generation of farmers ages out of the profession.6 Meanwhile, commercially-managed land like power line right-of-ways or airports would presumably have the potential for even more consistent long-term management.
Return on Investment
The beauty of storing carbon in agricultural soils is that it’s win-win-win. More soil carbon makes healthier, higher-yielding plants, which lead to higher profits for the farmer. This makes carbon sequestration an easy sell to a savvy farmer.
The same return on investment cannot be claimed for a suburban lawn or highway median managed for carbon sequestration. However, we are already investing an awful lot in those spaces: lawncare in the U.S. is a $50 billion industry, and is growing quickly.7 Rather than looking for a return on investment, we could simply shift what we are investing in. I for one would welcome a nice greenwashed line of regenerative lawncare products alongside the massive piles of Roundup and NPK fertilizers (some of the most destructive chemicals to healthy soil) at my local garden center.
Active Management.
Farmers already spend lots of time managing their soils, so achieving 4 per mille just requires them to do what they are already doing, but differently. By contrast, roadsides don’t get much attention aside from a yearly trim.
But anyone who has lived in suburbia and watched their neighbors obsessively mowing an already-perfect lawn, edging an already-perfect driveway, or trimming an already-perfect hedge, will find it hard to argue that farmland is more actively managed, per square foot, than many other types of land.
Changing the Narrative
The essential problem with the narrative of climate change is that everyday people are blamed for its causes without being invited to participate in its solutions. You, you irresponsible profligate sinner, are to blame for destroying the earth because you drive your car and fly in planes and buy plastic thingamabobs, but you are too insignificant to do anything to help. We will leave that to the “policy-makers” (whoever they are).
In actuality, corporate greed is responsible for destroying the earth, and we everyday people are being cleverly manipulated by an extractive, destructive system. And the “policy-makers” are clearly incapable of fixing anything. The only solution presented to a common person is to swap their existing consumption with something else—to buy an electric car instead of a gasoline car, to buy a recycled plastic thingamabob—while retaining the fundamental structure of extractive corporate greed. This is a system that stops defining us as “humans,” “people,” or least of all, “embodied souls,” but as that delightfully malignant term “consumers.” Saving the world is fine, so long as we keep consuming within the existing framework to do it.
Can sequestering carbon in the soil save the world? Definitely not. If we did meet the 4 per mille goal, and every square foot of earth’s soil increased its carbon by 0.4% per year, we would still only offset the increase in annual emissions. Much more significant change would be needed to bring our climate into a liveable equilibrium.
But the beauty of soil sequestration is that every single person on earth has access to soil right now. Maybe you have a lawn, maybe there’s a park down the street, maybe your workplace has a little mulched median in the parking lot, maybe there’s a tree planted in a sidewalk grate outside your apartment. Maybe, like me, you are lucky enough to steward a few lovely acres.
By caring for whatever patch of soil you have, by sequestering carbon in whatever small way you can, you can begin to shift the narrative. You can participate in an act of direct democracy: a vote by show of muddy hands. You can show that humans, en masse, don’t have to be the problem but can be the solution. What if 8 billion people weren’t an unbearable burden for the earth, but the necessary size of labor force needed to steward every patch of soil on this earth? What if sustainable change can only be brought about by intense, careful, thoughtful, small-scale management?
Managing soil is a transformative act that requires no investment, no resources, and no reliance on anyone else. You don’t need to spend 50 grand on a Tesla. You don’t need to vote for an ineffective legislator. You don’t need to change the mind of your gas-guzzling neighbor. You can just go out and tend your garden, and begin to change how we as humans relate to the earth.
Now for the 9 gigaton question: how do you sequester carbon in your little mulched median? Well, why not start by making biochar, which has the ability to offset 12% of current anthropogenic CO2 emissions?8
Or why not subscribe to this blog? I will be writing a lot more about ways to sequester carbon at home, and if you subscribe, every post will be delivered right to your inbox.
Or, how about sharing this post with 1299 people? You will collectively equal one farmer in sequestration potential!
Or just share your thoughts on all this.
Minasny, Malone, et al. (2017). Soil carbon 4 per mille. Geoderma 292, Pages 59–86. https://www.sciencedirect.com/science/article/pii/S0016706117300095?via%3Dihub
William A. Albrecht, Albrecht’s Foundation Concepts. Acres USA, 2011. Page 61.
Paustian, Larson, et al. (2019) Soil C Sequestration as a Biological Negative Emission Strategy. Frontiers in Climate. 1:8. https://www.frontiersin.org/articles/10.3389/fclim.2019.00008/full
Tallamy, Douglas. Birds and Plants: A Virtual Presentation by Doug Tallamy. Time 16:30. https://www.facebook.com/watch/live/?ref=watch_permalink&v=464353414521403
Carolan, Michael. (2018). Lands changing hands: Experiences of succession and farm (knowledge) acquisition among first-generation, multigenerational, and aspiring farmers. Land Use Policy, Volume 79, Pages 179-189. https://www.sciencedirect.com/science/article/abs/pii/S026483771731222X
Woolf, Amonette, Street-Perrott, et al. (2010) Sustainable biochar to mitigate global climate change. Nature Communications 1, Page 56. https://www.nature.com/articles/ncomms1053
For those of you who cannot or have no desire to make biochar, Judd comments that it's easy to buy online or at your local garden center, which is a good way to encourage the growth of the biochar industry.
I will add that it is quite expensive to buy. For example, a 1.5 cubic foot bag online is $50. I made 20 cubic feet, or around $700 worth, and it took me 8 hours (which mainly consisted of standing around a bonfire sipping cocoa), for an equivalent of $85/hr (that doesn't include time to cut and gather wood, which is not insignificant, though equally pleasurable).
Great piece, John! Re: the "9 gigaton question" -- if I'm not up for making biochar, beyond amplifying this wonderful blog post, I'm curious what options are available. Does simply working the soil sequester more carbon than leaving it alone?