These long, hot days have been full of weeding, transplanting, more weeding, breaking for ice water, and daydreaming of cross country skiing, reading books, and cooking feasts. During the winter months we take time to reflect on the previous year, plan for the upcoming season, and in general recoup. These past two winters Jeremy has sat down and calculated our carbon budget for us and the farm. A carbon budget, like a financial budget, is an inventory of our expenses (carbon costs, emissions), compared to our income (carbon sequestered through land management practices). We came to farming from a land health/environmental perspective and deep in our guts we feel like our practices are reaching towards our goals and values. Pulling the numbers together and working out our carbon budget has been a way to quantify our carbon emissions, assess the impact we’re making, and identify areas for improvement in management.
It was important for us to consider not just the farm business in our calculation but also our own personal carbon costs. Partly and feasibly, this done in response to the complexity of teasing the two apart. For instance, our electric meter doesn’t separate the air conditioner on the pack shed walk-in cooler, the heat lamps in the brooder, and the fans in the greenhouse from Jeremy’s loud reggae music on the record player. But further, and more importantly, we can’t ethically separate ourselves and our actions from our business. In this budget we also took into consideration our secondary carbon footprint including the carbon costs of shipping in materials, seed, feed, lifestyle choices, etc.
Our immediate carbon expenses over the past couple of years include electricity (coal), natural gas, gasoline for our car and Jeremy’s father’s truck, our farm laborers’ gasoline to-from work, and airplane travel for work and family/friend visits. We don’t have a tractor, tiller or mower, we do most work by hand and run errands by bicycle. Having grid-tied wind and solar power reduces our total emissions from electricity. Our secondary carbon emissions include things like the shipping and transportation of supplies to the farm over the course of the year as well as emissions of the manufacturer of those supplies (i.e. greenhouse plastic, drip tape, chicken feed). This also includes our personal secondary footprint (consumer habits, diet related emissions (damn Argentinian wines)).
These costs are added up to give us our total carbon emissions (expense) for the year.
Our carbon “income” is reliant on practices we employ on the farm that build long term stable soil organic matter. The driver of sequestering carbon in the soil is photosynthesis which takes carbon dioxide from the atmosphere and converts it into simple sugars that enter the soil profile either through decay of plant material or directly as root exudates. A large portion of this carbon is active, feeding soil biology and returning to the atmosphere in a relatively short period of time. But a portion of it becomes stable in the soil.Practices that we routinely use to build soil organic matter and sequester carbon include no-till/minimal disturbance, keeping the soil covered, having a living root in the soil as long as possible (YEAH – root exudates!), increasing diversity (different plants, different root types), including animals, applying compost, and planting perennials. We are constantly trying to improve our implementation of these practices on the farm.Quantifying how much carbon is sequestered in the soil through the implementation of these practices is the part of the carbon budget that requires the most estimation, approximation, squinting and pointing off towards the horizon. There are many studies that have looked at carbon sequestration across varied practices and we have taken conservative estimates from research on similarly managed land – organic, no-till, mixed annuals and perennials – in temperate zones.For the last two years (2016 and 2017), our carbon budget shows that we are sequestering more carbon in the soil over the course of a year than both our farm business and personal emissions combined. This includes our secondary carbon footprint. (AWYEAH!! …and more !!!!!)
We have a goal of increasing the amount of carbon we’re storing in the soil to the point where we are also sequestering carbon for one step forward from the farm, the emissions generated by our customers coming to pick up their produce at the farm stand. This can be done by either further reducing our emissions or by improving our land stewardship practices. We currently make deliveries to restaurants and natural food stores in town by bicycle and are enormously thrilled when customers are able to walk or bike to the farm to stock up on vegetables. We are just starting to figure out how to fit diverse cover crops into our vegetable rotation and from a carbon point-of-view still have a lot to learn about soil biology, pasture management, and so many other aspects of farming.The idea that we sequester more carbon in the ground than we emit over the course of the year through our actions seems like a little thing in the face of our mind-boggling climate crisis – increasing wildfires, rising seas and collapsing glaciers, displaced communities, vanishing forests, vanishing species. But it is something positive. Responding to climate change will take adaptation and mitigation, but over the long term will also require drawing down carbon from the atmosphere. Agriculture is guilty of being one of the largest emitters of CO2 over the past decades and it’s extremely empowering that well-managed lands are society’s best hope for sequestering enough carbon quickly enough to make a difference.
Here are some excellent resources we have found educational, helpful and inspiring:
Also, carbon comrades: If you are interested in specific numbers (well, specific ranges of numbers) and methodology, we’d be happy to send along our calculations. Because the range on estimating secondary footprints and carbon sequestration is so broad, we select higher estimates for emissions and lower estimates for sequestration from multiple footprint calculators and soil carbon studies.