Dirt, Carbon, Shit & Saving the World

Image source: Beiler, K., Durall, D., Simard, S., Maxwell, S., & Kretzer, A. (2010) Architecture of the wood‐wide web: Rhizopogon spp. genets link multiple Douglas‐fir cohorts. New Phytologist. 185 (2). p543-553.

What on earth possessed me to move into an apartment without a damn dishwasher? I hate – really, it’s not too strong of  a word – I HATE doing dishes. It’s mind-numbingly boring task without end. Ugh. I guess I was bamboozled by the picture windows and the “old world charm.”

Anyway, the only thing that gets me through this onerous domestic task is listening to captivating podcasts. For a podcast to capture my antsy mind, it generally has to be (1) sciencey or philosophical in nature, (2) somewhat unpredictable, and (3) well-produced and scripted. I rarely have the patience to listen to any unscripted (i.e. rambling chit-chat) podcast all the way to the end, regardless of content. That said, I do sometimes enjoy Russ Roberts’ wide-ranging, off-the-cuff, nerdily-titled interview show EconTalk. He has a wonderful way of selecting interesting guests, and then just totally geeking out with them on their area of expertise in a really authentic way that I find endearing, and occasionally even captivating.

This week I scrubbed and lathered away to a lively interview with Moises Velasquez-Manoff about his recent article on regenerative agriculture and climate science in the New York Times Magazine. I actually listened to the end. (You could too!) Here’s my take on Velasquez-Manoff’s story.


Dirt’s kind of a big deal. Farmers have understandably been obsessed with it since more or less the dawn of agriculture, but maybe the rest of us should be too. Good dirt is more than an inert substance you have to scrape out of your fingernails and sweep off your floor on an annoyingly regular basis. It’s an active, complex matrix of microbes, root systems, mycorrhizae, minerals, and other components, all constantly interacting with – and thus influencing – the plants, animals, people, and even atmosphere up here on the surface.

Wait, what? Dirt affects the atmosphere?

Yes, and it’s something I never really thought about until hearing this interview: dirt affects the atmosphere. Woah. It should come as no surprise then that many people who work with dirt (farmers, ecologists, soil scientists, backyard gardeners) are currently dreaming up ways this powerful matrix can be harnessed to mitigate or slow down climate change.


As I’m sure you already know (because if you’re reading this blog you’re probably at least [a] literate and [b] alive in the 21st century), anthropogenic climate change is being largely driven by too much carbon (largely in the form of CO2) in the atmosphere. And where did most of that carbon come from? Well, from the dirt, in the form of fossil fuels and coal.

Don’t panic, but I’m gonna show you one little chemical equation as a visual representation of the basic idea:

Image source: Johnson, M. P., “Photosynthesis” in Essays In Biochemistry Oct 26, 2016, 60(3) 255-273.

Long story short, carbon either goes UP into the air or DOWN into the ground.

Carbon goes UP via respiration (breathing), decomposition (rotting), or the big nasty one, burning. Carbon goes DOWN via photosynthesis when plants, green algae, or anything else with chlorophyll make some magic whoopie with sunlight, CO2, and water and produce all kinds of yummy carbohydrates.

And you know who likes yummy carbohydrates? Well, all of us, perhaps especially this author, presently gorging on a delicious bunch of sweet, sweet grapes… But also soil organisms – all those microbes, root systems, and mycorrhizae I mentioned a minute ago. These hungry little guys are our pathway for potentially getting some of that extra carbon in the air back down into the ground. As Velasquez-Manoff says, soil organisms literally “eat the sky.”


The story discussed in the interview centers around an idealistic Marin county couple who were utterly confounded by some unexpected twists and turns in their back-to-the-land homesteading adventure. John Wick and Peggy Rathmann started out with this idea that they could just buy up some old dairy-farming land, fence out the bovines, and let it “return to nature,” thus presumably creating an enchanting, wooded retreat where they could frolic about and recover from years of city living. Well. The project quickly turned into a mess: invasive weeds spreading unchecked, the oak trees dying off, nasty thistles everywhere laughing in the face of the herbicides now being doused on the land in a futile attempt to rout them out.

It turns out some ecosystems benefit from – or even require – the presence of grazers such as elk, deer, or even lowly domesticated cattle to keep the system healthy. Don’t get me wrong: improperly managed grazing is usually an ecological nightmare. But it seems that in the right place, at the right time, with the right management, grazers can potentially do a great deal of good.

Grazers contribute in at least two huge ways: (1) they love to nibble on spring grasses and the fast-spreading plants we call weeds, which makes room for healthier and slower-growing plant communities, and (2) they shit. Oh, how they shit. All those weed-eating grazers, they shit in vast – nay, majestic – quantities. They’re like walking grass-processing plants. And all that shit – when properly composted – returns mega nutrients back into the soil, including nitrogen and carbon. Remember those hungry little soil microbes? They LOVE that carbon, and eat it right up, and reproduce like crazy, and increase the soil’s capacity to suck up even MORE carbon.

Wick and Rathmann eventually figured out the utility of grazers in their local ecosystem the hard way, by trial and error and lots of hard labor, but they wanted to find out if what they learned could be validated, quantified, and used more broadly. So they recruited ecologist Whendee Silver to science that shit. What Silver and her students discovered – and the techniques they used to figure it out – is pretty damn amazing. Their findings on the dynamics of soil ecology seem to be part of a pretty important paradigm shift happening in that field right now, and if you’re into that kind of thing, you might want to check out the work coming out of the Silver Lab right now.

Saving the World

Honestly, I admire Wick and Rathmann: where others would have thrown up their hands and moved back into the city, these two dug in, worked with some smart scientists, and started to really figure out what was going on. The once-baffled Marin couple have become an active part of a broader movement to explore – and implement – the potential for regenerative agriculture and carbon farming to increase climate stability, food sustainability, and even the financial profitability of farming.

Ultimately, getting carbon back into the ground may end up being a relatively minor way of mitigating climate change. And as Roberts alludes to in this podcast, the economics of facilitating or incentivizing such a project are still a little iffy at the moment. But I’m certain it’s going to take a lot of different people working  in a lot of different fields on a lot of different strategies experimenting with a lot of different economic models to create the kind of change and adaptability we need moving forward into our uncertain future. So based on what I’ve learned so far, I think carbon farming will be an important piece of the puzzle – and it sure is an interesting one.

Have a wonderful day, friends, and don’t forget to feed the microbes!

A weird sidenote:

If you listen to the whole interview, you’ll notice that Roberts stumbles a little on the topic of climate change and then calls himself a climate “agnostic.” I was initially shocked: how is this supposedly empirically trained, PhD-having professor guy a climate “agnostic” in the year of 2018???  Generally speaking, the guy is a social-scientist rather than a biological scientist, so I’m not too sure about the depth of his understanding of the biological sciences and the epistemology thereof…but I did kind of want to sit with this one and try to imagine how he might be thinking. So here’s what I think: Roberts is clearly an intellectual, and likes to pore through data himself, so I kind of suspect he thinks he just hasn’t had the time yet to go through all the climate  research himself, but he’ll get around to it sometime (ha), so in the meantime he’ll just be “agnostic.” I would like to suggest, however, that the wisest course of action in these kinds of situations is placing one’s trust in the the topic experts. Not one of us will ever pore through all the data for all the topics that are relevant to our lives, to say nothing of developing the analytical background to appropriately understand and digest it all. So we need better heuristics. That’s a whole ‘nother post though. Stay tuned.

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