I have a piece on carbon farming in The New York Times Magazine. It tells the story of the people behind the Marin Carbon Project.
A lot ended up on the cutting room floor. At one point, the story was almost 50 percent longer than its current length. So a few things: First, if you want to know more about regenerative agriculture, I highly recommend David Montgomery’s book Growing A Revolution.
And if you’re interested in the bigger question of how civilizations have dealt with the inevitable decline of soil over history, his previous book Dirt: The Erosion Of Civilizations is fascinating on that front.
ABOUT GRAZING
There’s also a lot more to say about grazing. Some contend that, if done right, grazing can help to sequester carbon in soil. Some argue that grazing may even prompt grasses to exude more carbon into the soil, the idea being that as the plants try to recover from what amounts to a mauling by big animals, they offer carbohydrates to soil microbes in exchange for nutrients. So the right amount of grazing could, according to this line of thinking, accelerate the movement of carbon into the ground. I’d like to see some good studies on this fascinating idea.
Probably the most vocal proponent of the notion that grazing done right could help with the climate problem is Allan Savory. There’s lots of pushback against his argument. One problem is a lack of good, experimental science. See Oxford University’s recent report Grazed And Confused for a good counterpoint.
And yet, leaving aside the question of how many cows the planet can really support if they’re all grazing (as opposed to being fed grain in lots), I do think the idea that grasslands and grazers co-evolved—and that grasslands might be healthier with some amount of grazing—is intriguing and needs more research. After all, before they were plowed to make farmland, grasslands around the world sequestered enormous amounts of carbon. Think of the rich soil of the Great Plains or the Ukrainian steppe. Great herds of bison roamed the former. I’m not sure what roamed the latter before people dominated — perhaps horses and, before that, mammoths — but most grasslands, and even the tundra, do (or did) tend to host large, wild grazers. So it’s hard to imagine that some co-adaptation didn’t occur.
For anyone interested in a deep-time perspective on this, see paleontologist Gregory Retallack’s paper on how grazers and grasslands coevolved. They became so efficient at sequestering carbon, he argues, that together they cooled the earth and triggered the ice ages. Talk about draw down!
All that said, it’s worth remembering that John Wick, the protagonist in my story, did NOT find grazing to sequester carbon. His rangeland was bleeding carbon with just cows. It was compost, a soil amendment, that turned things around.
HOW MUCH CARBON CAN WE REALLY GET IN THE GROUND?
One final point about the estimates for how much carbon we can actually get in the soil. Right now, land and oceans absorbs nearly half of the carbon dioxide humans emit. The 4/1000 initiative (which, among soil scientists I queried, only Ohio State University’s Rattan Lal thought was realistic) assumes that land and oceans will continue to absorb this amount. What this means is that, according to 4/1000, carbon farming is only going to suck down roughly HALF of human CO2 emissions, not all of it. This detail didn’t make into the piece, but it’s worth keeping in mind. Even 4/1000 is not proposing complete carbon neutrality. It’s proposing that carbon farming can get us halfway there.
Some more nuances on the numbers. The UN’s recent “Emissions Gap” report points out that growing forests could suck up slightly more carbon than soils, which Pete Smith (more realistically, he claims) posits can sequester about 4.8 gigatons of CO2 yearly (see chapter 7). Meaning that, if we include forests — and if growing forests doesn’t conflict with growing food on cropland — forests and soils together could, very roughly, absorb perhaps 25 percent of human carbon dioxide emissions. Not bad. But here’s yet another thing to keep in mind. We’re contrasting this drawdown potential against just human-emitted CO2. That doesn’t include all human-emitted greenhouse gases (nitrous oxide, methane, etc.)
According to the “emissions gap” report, total human greenhouse gas emissions are 51.9 gigatons of CO2 equivalent yearly. Global CO2 emissions (just a subset of that) are 35.6 gigatons yearly. So in the context of All greenhouse gases, that 25 percent reduction I mentioned earlier shrinks to a measly 18 percent potential. As Smith says in the piece, we shouldn’t fool ourselves that this is all we need to do.
ABOUT FUNDING OF WHENDEE SILVER’S WORK
I noticed that a commenter faulted my piece for not revealing that Wick and Rathmann are wealthy, and that Rathmann is theoretically heiress to the Amgen fortune (her father founded the pharmaceutical company). These details on Rathmann’s background were in early drafts of the piece, but were ultimately cut. So goes journalism: you can’t include everything, and you don’t always make the decisions that other people think are right when cutting / omitting.
Even so, I need to point out the following. I state explicitly that Wick underwrote some of Silver’s early work. And the piece opens with the couple buying a 540-acre ranch, so the discerning reader will infer that these are people of some means.
The bigger issue here, though, is how science gets funded. Some of Silver’s funding came from the Rathmann Family Foundation, an organization that (like the Gates Foundation, which also funds science) gives grants out to causes it deems worthy. But Silver’s research was ALSO funded by the USDA, the 11th Hour Project, and the Lia Fund, among other orgs.
What you see here, I would argue, is the reality of what it takes to drum up funding to do potentially important science. There’s just not a lot of public money around, so foundations partly fill the gap.
Does it corrupt the science? Not necessarily. Would public funding be better? Perhaps, but that’s not always possible. Silver’s research IS published in peer-reviewed journals with funding sources plainly listed. And maybe most important for those who think that the Rathmann Family Foundation is corrupting, Whendee Silver’s research did NOT ultimately support John Wick’s hypothesis. In fact, her results argued against the idea that John Wick was so eager to see confirmed—that grazing sequestered carbon.
What’s so interesting about their collaboration is that, by following the evidence, they discovered something that neither of them anticipated.
However, as one skeptic points out in the piece, we DO need to see Whendee Silver’s research replicated — something that’s in the works — before we can assume that the finding is extremely robust. Meaning that, funding source aside, the reality of all science is that it needs to be repeated by different authors before we can treat it as something that, for example, is worth basing policy on. Until then, it’s just an interesting idea with SOME (in this case, quite good) evidence in its favor. But it hasn’t achieved the level of robustness, in my view, that would allow you to begin telling rangeland managers everywhere to spread compost on their land. That, of course, is noted in the article.
[Note: I changed the phrasing in the above graf 4/19/18]
