The Carbon Footprint of What We Eat

Today, we look at the carbon footprint of what we eat – starting with the findings of the Eat-Lancet commission – a collaboration between 37 experts from 16 countries that lays out the best diet for human and planetary health.

“Scientists have a [clear] moral obligation to clearly warn humanity of any catastrophic threat and to ‘tell it like it is.’” In November 2019, more than 11,000 scientists from 150 countries clearly and unequivocally declared “that planet Earth is facing a climate emergency.” CO2 levels are rising; the glaciers are melting; Antarctica is melting. The oceans are getting hotter, more acidic. Sea levels are rising, and so are extreme weather events. And yes, fossil fuel use is going up, like air travel––but so is per capita meat consumption. In fact, one of the solutions they offer to help the climate crisis is “eating mostly plant-based foods while reducing the global consumption of animal products.”

And what makes designing a sustainable diet so easy is that the same advice—like eat less meat—is good for both personal health––like reducing the risk of our number #1 killer––as well as for planetary health. The least healthy foods also cause the worst environmental impact. The foods with the most nutrition just so happen to be the foods that cause the lowest greenhouse gas emissions; so, you get this win-win effect.

So, let’s put it all together. If we are “to redesign the global food system for human and planetary health”—which is to say human health and future human health—what would it look like? Enter the EAT-Lancet Commission, “the result of more than two years of collaboration between 37 experts from 16 countries,” suggesting a cut in total meat consumption down to like an ounce a day—that’s like the weight of a single chicken nugget—all the while dramatically increasing our intakes of legumes (which are beans, split peas, chickpeas, and lentils), nuts, fruits, and vegetables––because we’re not just in a climate crisis, but a health crisis. Unhealthy diets cause more death and disease than smoking, more than unsafe sex, and alcohol, drug, and tobacco use combined. But we can address both crises at the same time by “increasing [our] consumption of [whole plant] foods and substantially reducing our consumption of animal source foods.”

Eating such a diet could save the lives of more than 10 million people a year and may just help save the world. The Paris Agreement had set out a boundary condition, an aspirational goal for a carbon budget to help prevent catastrophic impacts, and “staying within the boundary for climate change can be achieved by consuming plant-based diets.”

And the personal benefits may be comparable with or even exceed the value of the environmental benefits. The healthcare benefits alone for a healthy global diet—a predominantly plant-based diet, a vegetarian, or a vegan diet—could exceed the price of the carbon saved. We’re talking up to $30 trillion dollars a year saved from the health benefits alone.

Now, if the health of yourself, the planet, and your own children doesn’t quite motivate you, consider you may also be facing threats to the global beer supply.

And healthier diets don’t just reduce greenhouse gas emissions. Since “livestock production is the single largest driver of habitat loss,” reducing meat consumption is also the key to biodiversity conservation; ideally, perhaps, reducing demand for animal-based foods by increasing the proportions of plant-based food up to like 90 percent of the diet.

Livestock production is also a leading cause of soil loss, and water and nutrient pollution. Yet it appears to be a “blind spot in water policy.” “Despite the fact that animal products form the single most important factor in humanity’s water footprint, water managers never seem to talk about meat [and] dairy.”

But it’s not just animal products. I mean, yes, at least 80 percent of the deforestation in the Amazon is to raise cattle, and grow feed crops like soybeans to export to other farm animals––but also to make vegetable oil, most of which is from palm and soy. Both crops have been expanding, resulting in massive deforestation. It just seems “particularly egregious if that deforestation takes place for the sake of junk food.”

Not everyone agrees we should be moving to healthier diets, though. The World Health Organization actually pulled out of the EAT-Lancet Commission because of their promotion of a global move to more plant-based foods. See, if we focused on promoting predominantly plant-based foods, and excluding foods deemed unhealthy, including meat and other animal-based foods, such a diet could yeah, save 10 million lives a year, $30 trillion dollars, and help save the entire planet, but could lead to the loss of jobs linked to animal husbandry and the production of junk.

In our next story, we look at how much greenhouse gas is caused by the production of different foods — measured in miles driven or even light bulb hour equivalents. And yes, that’s a thing.

“Our eating habits are making us and the planet increasingly unhealthy.” Ours is a lose–lose situation; “a global transformation of the food system is urgently needed.” “In consideration of the mounting evidence regarding the environmental effects of foods,” for the 2015 to 2020 U.S. Dietary Guidelines, the scientific advisory committee “included for the first time a chapter focused on food safety and sustainability,” concluding: “a dietary pattern that is higher in plant-­based foods, such as vegetables, fruits, whole grains, legumes, nuts, and seeds, and lower in animal-­based foods is [not only] more health promoting [but also] associated with lesser environmental impact…” Despite unprecedented public support, this and other sustainability language was not surprisingly vanished from the Dietary Guidelines published jointly by the U.S. Department of Agriculture.

They’re not even sufficiently sticking to the science on healthy eating either, including no, or too lax, limits for animal-source foods, despite the available evidence. Even if they ignored planetary health altogether and just stuck to the latest evidence on healthy eating, it would have knock-on environmental benefits. Replacing animal-source foods with plant-based ones would not only improve nutrition and help people live longer, but could reduce greenhouse gas emissions up to 84 percent.

In general, plant-based foods “cause fewer adverse environmental effects” by nearly any measure. In terms of carbon footprint, all the foods that are the equivalent of driving more than a mile per serving are animal products. Here are the greenhouse gas emissions from various foods. Even though something like a lamb chop or farmed fish may be the worst, eating chicken still causes like five times the global warming than even something like tropical fruit. Though the climate superstars are legumes (beans, split peas, chickpeas, and lentils).

“For example, in the United States, substituting beans for beef at the national level could [alone] deliver up to 75 percent of the 2020 greenhouse gas emissions reduction target and spare an area of land 1.5 times the size of California” (not to mention the health benefits). And it’s not just greenhouse gases. Kidney beans required “approximately 18 times less land, 10 times less water, 9 times less fuel, 12 times less fertilizer, and 10 times less pesticide[s].”

So yeah, according to the prestigious EAT-Lancet Commission, more plant-based may be better, but even a shift towards a healthier dietary pattern “emphasising whole grains, fruits, vegetables, nuts, and legumes without necessarily [eating strictly-plant-based], would be beneficial.” In Europe, for example, just “halving the consumption of meat, dairy…, and eggs… would achieve [up to] a 40 percent reduction in nitrogen emissions” and greenhouse gas emissions and require about a fifth less land. “In addition, the dietary changes would also lower health risks,” reducing cardiovascular mortality, their leading cause of death.

Note, however, that “minimizing environmental impacts does not necessarily maximize human health.” Yes, animal products, dairy, eggs, fish, and other meat releases significantly more greenhouse gas per serving than foods from plants; eating added sugar and oil isn’t going to do your own body any favors.

In California, including more animal products in your diet requires an additional 10,000 quarts of water a week. So, that’s like taking 150 more showers a week. Even just skipping meat on weekdays could conserve thousands of gallons a week compared to eating meat every day, and cut your daily carbon footprint and total ecological footprint by about 40 percent.

Some countries are actually doing something about it. “The Chinese government,” for example, “has outlined a plan to reduce its citizens’ meat consumption by 50 percent,” whereas much of the rest of the world appears to be doing the complete opposite, pumping billions of taxpayer dollars into subsidizing the meat, dairy, and egg industries. We can certainly all try to do our part; however, an obstacle to dietary change may be “consumers’ underestimation of the environmental impacts of different types of food,” but may be aided by labeling. For example, imagine picking up a can of a beef noodle soup and seeing this. The carbon footprint of a single half-cup serving is like leaving a light on for 39 hours straight. And not some eco-bulb, an old-school 100-watt hot incandescent, compared to a meat-free vegetable soup—a difference of 34 light-bulb hours. You can imagine someone getting on your case for unnecessarily leaving on a light for 34 minutes, but this is 34 hours just eating a different half cup of soup.

Finally today, why don’t environmental groups advocate climate-friendlier diets? Let’s find out.

In what “was arguably the largest ever environmental protest in the world,” more than a million children, across more than a hundred countries, joined a “Global Climate March, demanding that governments act…” “The concerns of the young protesters are justified” and “supported by the best available science,” wrote a group of scientists and scholars. The enormous mobilization shows that young people have at least understood the situation, and “we strongly support their demand for rapid and forceful action.”

In terms of our food supply, there are all sorts of little tweaks, like feed additives that can reduce cattle belching, but put all those tweaks together, according to the prestigious EAT-Lancet Commission, and we’re only talking about reducing agricultural greenhouse-gas emissions in 2050 by about 10 percent; whereas, if we instead switched over to plant foods, we “could reduce emissions by up to 80 percent.”

All those cow, sheep, and goat burps only represent a fraction of the greenhouse gas emissions from animal agriculture; so, that’s why according to the IPCC, the official Intergovernmental Panel on Climate Change, becoming a so-called climate carnivore, just cutting down on ruminant products like beef, wouldn’t reduce greenhouse gas emissions as much as eating a healthier diet and limiting meat across the board. And, the fewer animal products the better.

“Which diet has the least environmental impact on our planet?” A systematic review found that eating completely plant-based may be “the optimal diet for the environment.” But it’s not all or nothing. Even just cutting down on meat to under an ounce or two a day could get you half the way there in terms of reducing greenhouse gas emissions. In terms of land use, a healthier diet, like a Mediterranean diet, may decrease your footprint by about a quarter, whereas even more plant-based diets can drop land use 50 percent or more.

In general, diets that include meat require about three times more water, 13 times more fertilizer, more than twice the energy, and 40 percent more pesticides than those that don’t. If you look even broader at the total environmental impact of omnivorous versus vegetarian versus vegan diets, looking not just at global warming, but ocean acidification, agricultural run-off, smog, ecotoxicity of the water and soil, and direct human toxicity of the air we breathe and the water we drink, and the soil we grow our food from, eating eggs and dairy may be nine times worse than plants. And, eating eggs, dairy, and meat may be 17 times worse than sticking to plant foods. Oh, and as a bonus, we could feed an additional 350 million Americans, like an entire extra country’s worth of people—more than if we eliminated food waste completely.

Changing meat-eating habits would seem to be a relatively cheap and easy way to mitigate climate change, in contrast to many other factors outside our control. However, surveys suggest few seem to recognize this option of eating less meat as a significant opportunity for helping. Research has shown that consumers often underestimate the impacts of meat consumption on the environment in general, and on climate change in particular. “The outstanding effectiveness of the less meat option (as established by climate experts) was recognized by… [only] 6 percent of [Americans sampled,],” and that’s after they were prompted to assume climate change is actually happening.

“There is an overwhelming scientific consensus that climate change is real and that we’re driving it,” but only about half of U.S. adults believe it. This is not by coincidence. Just like the tobacco industry tried to subvert the overwhelming evidence that smoking caused cancer, companies like “Exxon orchestrated climate change denial campaign[s] that stalled meaningful efforts… for decades.”

Certainly, environmental groups should know better, though. “None of the highest profile NGOs examined” appeared to want to feature the link between meat consumption and climate change. They were all aware of the evidence, of course, but evidently the science alone was not sufficient. It’s like another form of denialism that can become like a negative feedback loop, where it’s not popular to talk about, so you don’t talk about it, so it remains not popular to talk about, depriving the issue of the attention that it needs to break out.

And when they have messaged about it, environmental groups have tended to favor just asking for a moderate reduction in meat consumption––notable given the research demonstrating how much more powerful a lever it could be at the individual level to go even further. But, they don’t want to be seen as telling people what to do––instead advocating for small changes, like turning off your computer monitor at lunchtime or printing double-sided. But, “the cumulative impact of large numbers of individuals making [just] marginal improvements in their environmental impact” may end up constituting just a marginal collective improvement. Yet, we now live at a time when we need to make urgent and ambitious changes.