Local omnivorous vs. long distance plant-based- Which is more environmentally 'disastrous'?
A recent Twitter interaction, where I was criticized about a picture of my weekly grocery haul, motivated me to write this piece. I will include a photo below. The thesis of the argument is that most of the whole plants I bought came from other parts of the country or other parts of the world and that the green house gas (GHG) emissions emitted to transport these foods were more environmentally damaging compared to that of someone eating a local omnivorous diet. I appreciate constructive critiques like this and it made me pause and think more critically about my choices.
Using the metric of GHG emissions, there is no question that plants are less resource intensive than animals to produce for the purpose of food (Figure 1, 2 & 3). Beef requires 20 times more land and emits 20 times more GHG emissions per gram of edible protein (Citation). Currently, most people are aware of the climate change problem and GHG emissions are factored in when considering our food, energy, modes of transportation and even building materials and modes of manufacturing. That said, what if plant-based foods were mostly imported or transported thousands of miles to their final destination? And what if "the environmentally minded carnivore", eats local, free range, regeneratively produced beef and local vegetables? Would these scenarios at opposite ends of the arbitrary food-carbon spectrum make such a difference to warrant local beef in favor of bananas shipped from Costa Rica, or a grocery haul like mine? This article attempts to explore those questions and serves as a deeper dive (although certainly not a review of the totality of the literature) to explore a not-so-general example when it comes to greenhouse gas (GHG) emissions and the food we consume.
Transportation's contribution to the total GHG life-cycle of food is somewhere between 5% and 11%. One study concluded "that for the average American household, “buying local” could achieve, at maximum, around a 4-5% reduction in GHG". But "Shifting less than 1 day per week’s (i.e., 1/7 of total calories) consumption of red meat and/or dairy to other protein sources or a vegetable based diet could have the same climate impact as buying all household food from local providers." Additionally "eliminating the transport of food for one year could save the GHG equivalent of driving 1,000 miles, while shifting to a vegetarian meal one day a week could save the equivalent of driving 1,160 miles" (Citation). Powerful findings that suggest that the type of food (i.e beef vs, beans) plays a much more powerful role than buying food locally.
On the other hand, this article written by British authors, did a comparison of several foods and found that "Analyses of green beans grown in Kenya and pineapples grown in Mauritius suggest that the emissions from flying these products from their points of production to the UK form the greatest proportion of the overall carbon footprint of the products (89 and 98%, respectively), and in the case of beans the overall footprint of Kenyan produce is 10 times greater than UK-grown produce." However, the article concluded "The results do not offer any support for claims that local food is universally superior to non-local food in terms of its impact on the climate or the health of consumers.
As a whole, "Food is responsible for approximately 26% of global GHG emissions (Citation)."
There are reports of farms like White Oak Pastures in Georgia and Carman Ranch in Portland, that are referred to as 'regenerative agriculture'. According to Regeneration International...“Regenerative Agriculture” describes farming and grazing practices that, among other benefits, reverse climate change by rebuilding soil organic matter and restoring degraded soil biodiversity – resulting in both carbon drawdown and improving the water cycle. A report, sponsored by General Mills, on White Oak Pasture found that their property provides a net carbon sequestration. Meaning, the farm puts more carbon into the ground than they are emitting. Quite a claim, especially for a farm that raises resource-intensive beef cattle. My own knee jerk reaction to this type of farming is positive. I am in favor of this. However, a solution is not viable if it's not scalable. Is this type of farm and farming scalable for most or all of the US, considering a growing population and demand for meat? And if it is plausibly scalable, what is the time table for this to happen?
However, this study throws cold water on the notion of grass fed beef being more environmentally sustainable and emitting a smaller carbon footprint. It looked at 3 different beef production cycles comparing conventional, natural and grass-fed. It found that conventional beef finished on a feed lot and given growth-enhancing technologies had the lowest carbon footprint because it required the "fewest animals, and least land, water and fossil fuels to produce a set quantity of beef". Where as the grass-fed beef had the highest carbon footprint. This article corroborates the findings above by stating "Modern, intensive livestock systems, especially for beef, offer substantially lower land requirements and greenhouse gas emissions per kilogram of meat than traditional, extensive ones." The chart (Figure 4) included in this study is impressive and shows that the GHG emissions of pulses and plant-based sources isn't in the same ball park as animal-based protein sources. A downside to this type of regenerative or grass-fed farming is that it is requires more land to produce the same amount of meat when compared to feed lot operations. Most of the beef sold in the US is not grass-fed either. "According to Dr. Dale Woerner, assistant professor with the Center for Meat Safety & Quality at Colorado State University, 97% of the beef produced in the U.S. is grain-fed feedlot beef, while the other 3% is grass-fed (Citation)." Not only is a very small fraction of the beef sold actually grass fed, but 75-80% of the grass-fed beef sold in the US is grown abroad in places like Australia, New Zealand and parts of South America (Citation). And even if you bought burger patties from the regenerative farms mentioned, unless you lived within driving distance, you would still have to have those items shipped to your house, further emitting carbon.
Realistically, if someone lived a couple of miles down the road from White Oak Pastures with their claimed net-carbon sequestration, and was also consuming local, in-season produce, by the numbers, it could be conceived that their carbon footprint would be lower than someone who eats an all plant-based diet that is imported or transported long distances. However this scenario is unrealistic for the vast majority of American's, let alone the global population. If the numbers on carbon sequestration at White Oak Pastures is to be believed, I would be in favor of more farming practices like this. But, it would take decades for farms to convert to regenerative agriculture. Transportation and energy are the largest sources of GHG emissions. As I've argued in the past, switching modes of transportation for many of us is not easy, whether that be riding a bike, taking the bus or buying a Prius. Additionally, equipping solar panels on your house is not frictionless or cheap. Believe me, we explored this option very recently and the hoops that one has to jump through relative to the benefits makes the process loathsome and discouraging. However, the food in your refrigerator turns over weekly and is extremely modifiable relative to modifying transportation and energy requirements. One week, you could buy beef, and the next week you could buy beans and make a significant impact on your personal carbon footprint. Multiplying that by your family, your community and the country could make significant changes. We can make a difference if we follow the science and vote with our wallets.
In Episode 69 of my podcast, World Resources Institute Vice President for Science and Research Janet Ranganathan said:
"Only about 6% of the green house gas emissions from the food system are actually from the transportation of that food. Where as 80% of them come from the agriculture and land use sector. You should think about food miles, but it isn't the largest driver of green house gas emissions. So maybe getting something that's produced further away that was produced more efficiently, is actually going to have lower GHG emissions than something that was produced more intensively that is locally sourced."
You can play this section of the podcast via the embedded player below:
Macro Four's observation that my food traveled a fair distance to get to my grocery cart is right. However, the argument that even a local, meat-based diet may be more environmentally friendly than a plant-exclusive diet that travels a fair distance is weak. The data that I found shows that plants have a low environmental footprint, that 'food miles' contribute a very small proportion of the total GHG emissions, and that the production of the food contributes the vast majority of the emissions. Please see Figures 1, 2 and 3 for a pictorial representation of the production costs of various foods. In reference to the tweet above (Figure 5), I feel strongly that this is not cherry-picked data and that not only are plant-based burgers significantly more environmentally friendly than traditional beef burgers, but the entire diet, regardless of where you get the food, is superior in terms of GHG emissions.
Action Items to lower one's carbon footprint:
Buy more in-season, local produce. I concede the argument that my groceries in the picture above could have been sourced more locally, especially in the summer in Upstate New York.
Eat less meat, in particular ruminant animals (beef). There's no way around this for the vast majority of us.
If meat is on the menu, search for local, regenerative agriculture farms. Make connections with local farmers at your farmers market.
Buy what you need and waste less food. " Approximately one-quarter of food produced for human consumption goes uneaten."