A veritable slew of articles can be found online that discuss the carbon footprint of various diets, and all of them point toward a sizable reduction in carbon and other greenhouse gas output for people who don’t eat meat, with vegans having the smallest dietary carbon footprint of all. Looking at the numbers published in the above articles, we can estimate that the total dietary carbon footprint in the United States is about 800 million tonnes of carbon dioxide. The total carbon emissions by the United States is estimated to be about 5,300 million tonnes of carbon dioxide. Going just by these numbers, the dietary carbon footprint represents about 15% of the total.
The upshot from the articles about a vegan diet compared to a standard diet finds that the vegan diet results in about a 1.5 tonne reduction in carbon dioxide per year per person, from about 3.0 tonnes for the standard American diet down to 1.5 tonnes for vegans. As of 2012, vegans represented about 2% of the population of the United States. This is a rapidly growing demographic, but we will stick to that figure for now. This means that there are about 6.4 million vegans in the United States, in total contributing 9.6 million tonnes of carbon dioxide output per year. Despite being 2% of the population, they contribute only 1.2% of the total dietary carbon footprint. What if 10% of Americans were vegan? In that case, the total dietary carbon footprint would be reduced by 1.5 for the 8% of Americans who switch from the standard diet to a vegan diet. This would represent 25.6 million new vegans in the United states, each contributing 1.5 fewer tonnes of carbon dioxide output per year, for a total reduction in emissions of 38.4 million tonnes per year.
Compared to the total emissions of about 5300 million tonnes, this may seem like a largely inconsequential amount. But, emissions do not need to be brought to zero to eliminate excess carbon buildup in the atmosphere. According to the United States Geological Survey, a reduction in carbon emissions by 75% is required to bring emissions and sequestration into a sustainable equilibrium, where a net gain in carbon is no longer being added to the atmosphere. 75% of 5300 is 3975, meaning that if the United State’s vegan population rose from 2% to 10%, the 38.4 million tonnes in reduction of carbon dioxide output would represent about a 1% reduction in total output. That is starting to register, and it doesn’t even begin to take into account the other environmental plusses of fewer people consuming meat, such as lower total livestock water consumption, more efficient land use to feed people instead of livestock, and lower emissions of greenhouses besides carbon dioxide, such as methane which, pound for pound, is a bigger problem than carbon dioxide.
It of course isn’t realistic to hope that 25.6 million people will become vegans overnight, or even in a few years. Perhaps in a generation or two this could happen — and I think it will — but, our climate problems require faster, higher-impact solutions. Back in 2010, I caught this TED Talk by Graham Hill, discussing why he became a weekday vegetarian. His argument was, in essence, that cutting meat out of his diet for most of the week was a good way to lower his carbon footprint. I agree. Some vegans are militant, with an all-or-nothing approach to veganism and, while I respect their commitment, I am open to people dipping their toe in and making whatever positive changes they can. We can see that, mathematically, if everyone committed to one vegan day per week, that would be more effective than increasing the vegan population from 2% to 10%. That would represent the equivalent of 44.8 million new vegans (one seventh of the total non-vegan population of America). This, in turn, would result in a reduction in the country’s dietary carbon footprint by about 67.2 million tonnes. If everyone followed Hill’s advice, but went all the way to vegan instead of vegetarian five days out of the week, we’re looking at a reduction in the dietary carbon footprint of 336 million tonnes per year. That would represent 8.5% of the total carbon dioxide reduction needed to bring the country into a carbon neutral state.
We can compare this to how much your choice of car affects your overall carbon output. The typical American drives about 14,000 miles per year in a car that gets about 25 miles/gallon. What if these drivers switched to a car that gets 35 miles/gallon? Using the car carbon footprint calculator, we find that such a switch would result in a decrease of annual carbon emissions from driving from 4.65 to 3.32, or 1.33 tonnes per year. Of note, this is less than the reduction one sees from switching to a vegan diet. Not every American drives or has a car. There are approximately 180 million cars registered in the United States. This is not counting utility vehicles, construction vehicles, trucks, and so on, but generally just everyday cars owned by everyday people. If the average mileage of those 180 million cars jumped from 25 miles/gallon to 35 miles/gallon, we would see a national decrease in carbon emission from privately owned cars of about 240 million tonnes per year. This is less than what we would see from Americans switching to a vegan diet on weekdays. It is about equivalent to Americans eating a vegan diet 3.5 days a week, or half of the time. In other words, this would be equivalent to Americans choosing a vegan option for half of their meals, or Americans cutting their meat and dairy intake by about half and replacing that with vegan items.
It is an expensive proposition for Americans to buy new cars and improve their gas mileage. It is an entirely unrealistic proposition to suggest that Americans in certain areas with certain schedules switch from cars to public transportation. It is neither expensive nor unrealistic to eat a bowl of cereal with soy milk instead of milk, or to eat a veggie burger instead of a beef burger, or to have rice and beans instead of meat and potatoes. This is something everyone can accomplish at least half of the time.
Obviously, a major shift in dietary practices in the United States would be just one small change on the way to climate salvation, but it is not that hard, and it lessens the burden on the system elsewhere to make rapid changes. It is not hard to at least try this once a week, or just one meal a day, or just on the weekends, or just the weekdays. You don’t have to commit to an entire vegan lifestyle to make a difference. You will no doubt find that it is easier than you think to do more than you set out to do, too. I started by trying vegetarianism for two weeks, just to see if I could do it. I was a meat lover my whole life until then. I never looked back and now I have been a vegan for years.