Useful Resource: Low Carbon Diet Calculator
Thursday, June 25, 2009 at 9:32AM 
"Sustainable food" is food that has the least harmful impact on the earth, water and atmosphere, but calculating how sustainable a particular food is can be tricky business. There's more to sustainability than just greenhouse gas emissions, but when it comes to carbon emissions, one good starting point is a carbon footprint calculator.
Back in 2006, an anonymous British group launched the Food Carbon Footprint Calculator, and last year the food company Bon Appétit Management launched the Eat Low Carbon Diet Calculator, which I've been playing around with a bit. The site works with a drag-and-drop function that allows users to drag food items into a cast-iron skillet, and the thermostat at right rises according to the estimated abount of carbon it takes to produce that item.
There are a few notable omissions: The calculator doesn't differentiate between locally-grown and food that has been shipped thousands of miles, and although you can choose between seasonal and unseasonal menu items, it doesn't distinguish between factory-farmed and small-scale, family-farmed foods. Similarly, there is no organic vs. conventional rating on the calculator, which Bon Appétit explains in the FAQ section:
Just knowing a food is certified organic doesn't tell you whether the carbon points are lower or not. Organic foods are grown without synthetic pesticides or fertilizers, which does reduce the carbon points. However, many large scale organic producers use mono-crop systems and require other types of inputs (such as transporting bees long distances to pollinate crops or importation of grains to feed cattle). The types of food you choose to eat such as meat vs. dairy vs. vegetables and the amount of food you waste will probably influence your decision more.
The basic point is valid, and I accept that there are too many different types of farmers and producers under the organic umbrella to assign a specific carbon rating to the entire industry. However, simply because the industry and government oversight are imperfect doesn't mean that organics are no different than conventional foods, as Bon Appétit suggests. At least one long-running study from the Rodale Institute (PDF) shows that organic farming methods tend to create carbon "sinks" that remove carbon from the atmosphere and sequester it in the soil.
-Mark
Reader Comments (3)
Mark - I've got a little bone to pick.
I feel like things either are or they aren't sustainable. That you can't have gradations of sustainability, because the definition of an unsustainable practice is one that will eventually fail, if carried on.
Is something "more sustainable" if it takes longer to fail?
You say that "Sustainable food is food that has the least harmful impact on the earth, water and atmosphere." Is that right? I mean, what about food that has the SECOND least harmful impact on these things - is that not sustainable?
not to be a jerk or nothing.
I’m not a farmer, and I’m certainly not an expert, but I don’t think that any man-made agricultural system is ever perfectly sustainable. Nature is the model of sustainability that organic farmers and permaculturalists strive to imitate, but that they will never quite be able to reach. So my saying that sustainable food has the least impact on the environment is an acknowledgment that no agricultural system is perfect.
You say it’s more black and white than that, but where do you draw the line? How do you determine if something is or isn’t “sustainable”? By filling out a USDA checklist?
If ever there were a model of sustainability I think it would be something similar to the techniques of the Inca, which are still carried on by Peruvian farmers today. But even there, farmers have to introduce manure, ashes and compost to replenish the soil, and farmers are known to fallow their fields for as many as 6 out of every 7 years.
Is something "more sustainable" if it takes longer to fail? I'm not sure what you mean by "fail" here. From what I gather talking to farmers, farmers are constantly making mistakes (failing) and correcting for them, instead of setting a course and never veering from it.
I agree with everything you write - if anything is sustainable, then it's nature, and farmers are doing their best to imitate it. Natural process replenish soil because there are animals who poop and plants that die. Farmers bring poop in "artificially" to emulate that process.
What I'm saying is that when we talk about sustainability, we should make sure that we're not using a catchall term for "good for the earth". Because it means something specific, that's all.
By "fail" I meant that if the current process is carried out indefinitely, that it would collapse because of lack of resources to continue. Drilling for oil to drive cars is clearly in this category.
But when you describe the farmer who constantly updates her strategy, it's difficult to talk about sustainabilty, and instead we should talk about concrete things like carbon footprint (which is what the calculator above does) or economics (can this farm continue to be organic and green with these prices and these inputs.)
Does that make more sense?