Early in June, even before the results of this study were published, the UN issued a report suggesting that "a global shift towards a vegan diet is vital to save the world from hunger, fuel poverty and the worst impacts of climate change."
In a study published today in the peer-reviewed journal, Global Environmental Change, climate impact researchers modeled the impact of future changes in food consumption and technological mitigation of agricultural greenhouse gas emissions on the effect on climate in a scenario over the next 45 years, to 2055. The global model combined information on world population, income, food demand, and production costs with environmental data on potential crop yields. The calculations show that global agricultural greenhouse gas emissions (e.g., methane and nitrous oxide) increase significantly until 2055 if food energy consumption and diet preferences remain constant at 1995 levels. However, the agricultural emissions of greenhouse gases have increased steadily over time, and show no sign of slowing down. In fact, in 2005 they accounted for "14% of the total anthropogenic greenhouse gas emissions." Assuming world dietary preferences continue to shift towards animal-based foods, i.e., meat and milk, in regions and countries that have typically not favored these food sources, emissions will rise even more.
To gain an idea of how one person's food choices impact the climate, I consulted The Nature Conservancy's Carbon Footprint Calculator. As a baseline, "in 2004, the United States emitted 7074 million metric tons of carbon dioxide equivalent green house gases. This equals approximately 27 tons per person." An "average" American's carbon emissions from diet, calculated only on the basis of a predominantly meat-based, non-organic diet alone, is 4.1 tons of CO2 and carbon-equivalent emissions a year. When I changed the selections to more accurately reflect my diet, or the diet of any "average" vegan or vegetarian, ("I eat meat in my diet... never" and "I eat organic food... most of the time") the CO2 and carbon-equivalent emissions decreased to 0.6 tons per year, 85% below average. The cumulative power of vegans and vegetarians to positively effect the environment is easy to calculate, even if you're not great at math. Playing with the calculator is fun, and informative. Even simply reducing meat intake to "Rarely" from "Most days" and taking the middle road with respect to organics, "I eat it sometimes" reduces individual emissions (again, from diet alone) to 1.3 tons per year, 69% below average.
If you're curious about how the calculator actually works, this gives a very detailed explanation of how your carbon footprint is calculated. The following excerpt about "Food and Diet" outlines the impact one person's meat-heavy, non-organic diet has on greenhouse gas emissions in very clear terms.
"Average: Agricultural activity (crop, land, and animal including management, and including farm vehicles) accounts for 7% of all greenhouse gas emissions in the United States, with 91% of that being from methane and nitrous oxide emissions.
Behaviors: Vegan and vegetarian diets emit 72% and 42% less than the typical American diet, respectively. A heavy meat diet emits 24% more than the average. For the organic food responses, "Most of the time" reduces your emissions by 29%, "Sometimes" reduces emissions by 15%, and "Never or rarely" is the average emissions figure."
Behaviors: Vegan and vegetarian diets emit 72% and 42% less than the typical American diet, respectively. A heavy meat diet emits 24% more than the average. For the organic food responses, "Most of the time" reduces your emissions by 29%, "Sometimes" reduces emissions by 15%, and "Never or rarely" is the average emissions figure."
It's pretty clear that every small choice makes an incremental, yet measurably cumulative effect on the environment, and for our future. Something to think about the next time you're in the grocery store. Start small: eschew the hamburger for a veggie burger once in a while.
*Source: Potsdam Institute for Climate Impact Research (PIK) (2010, June 28). Conscious choice of food can substantially mitigate climate change, research finds. ScienceDaily.