Can What We Eat Help Mitigate the Effects of Climate Change?

According to a number of studies, livestock production is responsible for a large part of global greenhouse gas emissions. 

In 2018, environmental researcher Joseph Poore and agricultural engineer Thomas Nemecek published a study in Science about the global impact of food production. Analyzing data from around 38,000 commercial farms in 119 countries, they calculated that a quarter (26%) of global emissions comes from food production, and more than half of this figure (58%) is due to animal production. More specifically, they found that 50% of emissions from farmed animals come from beef and lamb production. Other studies put the livestock sector as responsible for around 14.5% of total anthropogenic greenhouse gas emissions. 

Cows produce a lot of methane as their digestive systems process food. In fact, ruminant livestock can produce up to 500 liters of methane a day. This is estimated to contribute to just under 2% of global warming. Methane remains in the atmosphere for about 12 years — much less than CO2, but is more damaging in terms of global warming, due to its greater ability to trap heat in the atmosphere.  

According to Food and Agriculture Organization (FAO), cattle represent up to 65% of livestock-related emissions. Pigs, chickens, and small ruminants contribute to this by 9%, 8%, and 6%, respectively. 

Another damaging aspect to livestock is the deforestation and clear-cutting used to create pasture. Fewer trees and other plants limit the amount of CO2 which can be absorbed. Let’s not forget that animals must be fed too —and crop production for animal feed adds another 6% of carbon emissions.  

Combine the energy used for the processing of raw products, packaging, transport, and retail (such as refrigeration) — they all demand an extra use of energy that is not necessarily clean. Sure, we could try to reduce our individual environmental footprint by eating local, but total transport emissions account for only 6% of food-related emissions globally, so this would not be enough. 

So what can we really do to diminish our diet-related emissions?

Plant-based diets 

In August 2019, the United Nations’ Intergovernmental Panel on Climate Change (IPCC) published a report detailing human influence on global warming and climate change effects that are already being observed around the world. 

The document points to methane, carbon dioxide, nitrous oxide, and sulfur oxide emissions as the main anthropogenic emissions. And the production and consumption of meat and dairy products highly contribute to this. This is why the organization recommended that people switch to plant-based diets whenever possible. 

"We're not telling people to stop eating meat. In some places, people have no other choice. But it's obvious that in the West we're eating far too much," said environmental scientist Pete Smith to the BBC. 

Statistics from North American Meat Institute (NAMI) reveal that in 2017 alone, American meat companies produced 26.3 billion pounds of beef (11.9 bn tonnes), 25.6 billion pounds of pork (11.6 bn tonnes), and 150.2 million pounds of lamb and mutton (68.1 mn tonnes). But while 59% of Americans claim to be concerned about climate change, the consumption of meat in the country has increased by 40% since the 1960s. In fact, Americans eat more meat than what national dietary guidelines recommend and the U.S. holds the second place in meat consumption per capita.

Plant-based diets still have an impact on the environment. Researcher Joseph Poore warns that air-freighted fruit and vegetables, “can create more emissions per kilogram than poultry meat”. Even slower shipping methods can have a big carbon footprint. This is because many fruits and vegetables are shipped in refrigerated conditions. In fact, 15-20% of the fuel used to transport them is consumed by refrigeration.

Although large vessels, such as freighters, can transport a lot of produce, the carbon emissions depend a lot on how much refrigeration is used. For example, bananas can have low emissions as they are transported at 57.2ºF (14ºC), whereas an apple from New Zealand needs to be kept at 32.9ºF (0.5ºC).

But even if you always eat local, you need fertilizers for the plants to grow properly and these also have an environmental impact. The manufacture of synthetic fertilizers releases methane and CO2 into the atmosphere, and once they’re used on the land, they emit nitrous oxide.  

Furthermore, there is agricultural machinery involved in the whole process of planting and harvesting fruits and vegetables. Tractors generate their own greenhouse gas emissions, too.

But overall, the production of plant-based foods is less polluting than meat production. Productions of a kilogram of peas emit a kilogram of greenhouse gases (GHG), while production of a kilogram of beef emits 60 kilograms of GHG. This is why in the chart of food-related emissions, field-grown vegetables are at the bottom, according to the Journal of Cleaner Production.

Knowing this, some food companies are scrambling to introduce a wide number of meat-free products to the market, such as leghemoglobin-based foods. Leghemoglobin is a heme-containing protein found in legumes. Through bioengineering, it’s being used to create meat-free products that taste and look like real meat.

Sustainable agriculture

Avoiding meat is not a possibility for many people, especially those in developing countries where other sources of protein are scarce. And certainly, it wouldn’t necessarily be good news if the entire world became vegan overnight (What would we do with the animals? Where would meat producers work? Where would we get organic fertilizers? What about the ecosystems that rely on grazing animals?).

This is why scientists are working on several mitigation strategies. For example, UC Davis researchers are trying to reduce cows’ emissions by making them “less gassy”.  In 2019, they actually managed to decrease methane emissions by 60% when they added 1% of an easy-to-digest red seaweed to the cattle’s diet.

Similarly, Dutch health company Royal DSM created a molecule that restrains methane production. It hopes to include it in cattle’s feed in the future so that farmers can keep cattle’s methane from even forming. 

Meanwhile, in New Zealand, researchers have genetically identified microbes living in cattle’s stomachs which produce methane. If we could “attack” these microbes with a vaccine, we would effectively have an anti-methane vaccine. 

Less complicated options include selective breeding. The more "convenient" cow breeds for environmental purposes are those which grow bigger and faster. The reasoning is that cows which are slaughtered earlier spend less time releasing methane into the atmosphere. 

Right now, this may be the best approach for farmers and livestock companies until anti-methane vaccines and anti-methane feed are fully available in the market. Or until people begin to switch in larger numbers to meat-free meat products.

What about us, then?

You still can do a lot to reduce your individual environmental footprint through buying foods that use less energy to produce and transport, eating less meat overall, and trying to stick to foods that are grown locally and are less carbon-intensive. But the keyword here is “individual”. According to one line of thinking, it doesn’t really matter if it’s only you. Individual behaviors didn’t cause climate change and their contribution to reverse the situation —a situation that industries created — is minimal. 

As columnist Jay Michaelson wrote in The Daily Beast, “Cutting back on flying while allowing cars and trucks to operate as usual is like drinking diet soda with a bacon double cheeseburger.” 

If everybody agreed on becoming vegan, meat producers would surely be forced to migrate to other areas of food production and we’d have fewer amounts of GHG emissions linked to livestock. But given that it’s not really possible for everybody to agree on something like that, the choice to become meat-free is still personal — and therefore, perhaps not as significant as we’d like it to be. 

We do need cooperation to make a change, but individuals and small groups (only 6% of America are vegans) alone do not make much difference. The changes must be larger and systemic, and especially, they must involve the industries responsible for GHG emissions. Not only the livestock industry but also the transportation industry (which is already investing in cleaner vehicles), the energy industry, and others.

We may need more than good intentions for that. We may need new regulations and laws to induce industry to make the switch to less energy-intense methods of production. 

In any case, “us” should really be plural, in a structural sense, in order to fight climate change.