“Carbon Positive by 2025!” reads a line of text on a carton of Horizon Organic Milk, a claim I’ve been seeing more frequently on the products of both large and small companies. Perhaps you have too. If so, I am here as the bearer of bad news. I aim to convince you that your default reaction should be skepticism.
When I set out to write this post I planned on using Horizon as a case study. But that has proved more difficult than expected. I can find a bit more detail about the project from old articles, like this one, that date from a few years back. But Horizon’s website itself has general language about sustainability, regenerative practices, and reducing carbon emissions, I can’t find anything about aiming to be net carbon positive, except in reference to one niche line of milk. The links in this press release from Horizon no longer work, meaning I can’t find the reports the carbon positive plan was based on. Perhaps Horizon has decided the target isn’t achievable and it’s just taking time to work through a backlog of packaging. Or maybe it’s the opposite. Perhaps the whole Horizon website will soon be updated to make the carbon positive claim central.
Still, there’s enough on the website to take a good guess at how Horizon is or was going about pursuing a goal of carbon positivity. By encouraging its farmers to adopt a suite of practices like eliminating tillage, rotating crops, and managing grazing, some carbon could be returned to the soil in the form of organic matter. The rest of the deficit would be made up by purchasing carbon offsets in the form of tree plantings.
The first problem is exactly what carbon capture number we ascribe to regenerative farming practices. I believe they can increase the amount of carbon stored in soil over the long term. But how much carbon, in what circumstances, and how long it stays there, are extremely contentious topics. Believe me, as a farmer I’d like nothing more than to be able to confidently make big claims about the quantity of carbon good grazing management has sequestered in my pastures. I’m reasonably confident it’s quite a bit. But as the article linked above and the others in the series should make clear, there are too many variables and nature is too adept at defying our expectations to model something as complex as the carbon cycle from atmosphere to plants to bacteria to soil and back. Even on the same farm what happened one year cannot predict what will happen the next.
To believe Horizon’s claims, I would want to see how they are measuring and modeling soil carbon sequestration. I am aware of no good study that comes close to proving carbon neutrality at any scale. I’m not an expert, so maybe I’m just unaware. If you know of such a study, please send it my way!
The second problem is carbon offsets. The logic goes like this: trees are mostly carbon. By planting trees, we extract carbon from the atmosphere and store it in plant form. It’s actually very similar to the process by which regenerative farming seeks to sequester carbon, though its superior in two significant ways. First, it’s much easier to calculate the carbon stored in trees than carbon stored in soil, since trees put so much of their mass above ground where it can be measured. Second, trees are long lived, meaning the carbon stays put so long as the trees don’t rot or burn. Of course, the benefit of good farming is that it can produce high value, nutritious food while also taking care of the land.
There’s an even bigger issue, one with the whole scheme. A moment ago I mentioned that trees are a fairly stable form of carbon storage. They are, when compared to agricultural land. Carbon sequestered in soil is ephemeral in that maintaining it relies on consistently excellent management, year after year. Plowing once or changing grazing for a single year can massively degrade organic matter, releasing much or all of the carbon that has been painstakingly added to the soil. But even trees, with potential lifespans measured in centuries, are transient when compared to carbon currently stored as coal and oil.
I’m just a simple farmer, but I can’t wrap my head around how we’ve agreed that this is a valid approach. We are taking fossil fuels — carbon that has been sequestered for millions of years and will remain so if left alone — and burning them. To offset this we are pulling carbon out of the atmosphere and turning it into trees, or (maybe) putting it in the soil, where it will only remain as long as the land the trees are growing on remains forest or the fields remain perfectly managed. When the land use changes, all of the carbon in trees and soil will join the carbon that it supposedly offset in the atmosphere.
It’s hard to articulate why I care so much about this. After all, I am glad that Horizon encourages its farmers to use good practices. I think planting trees is wonderful. Part of it is moral — I often take industrial agriculture to task for lying and obfuscation, so I don’t like to see it in my peers — and part of it is pragmatic — I don’t want people to think non-solutions work. But my biggest issue with it is that I just want clarity. I want us to at least try to use words and phrases to reflect reality. In the world at large as in farming the trend seems to be in the opposite direction, but I nevertheless think we should resist it.