Does what you eat have a climate change impact? Yeah. Yes. Around one-quarter of the planet-warming greenhouse gases that humans emit each year are responsible for the world’s food system. This involves raising and harvesting all of the plants , animals and animal products we consume, including beef , chicken, fish, milk, lentils, rice and more, as well as refining, packaging and exporting food to markets across the globe.
Huge reserves of carbon are released into the atmosphere, which heats up the earth, as forests are cleared to make way for farms and livestock. When their food is digested by cows, sheep and goats, they burp methane, another strong greenhouse gas. Also, large sources of methane are animal waste and rice paddies. Finally, fossil fuels, both of which create emissions, are used to run farm machinery, manufacture fertiliser and ship food globally.
Meat and dairy, particularly from cows, have an outsized effect, with livestock accounting for about 14.5% of the world’s annual greenhouse gases. That’s about the same amount as the total emissions of all the cars , trucks, planes and ships in today’s world.
The average greenhouse gas emissions associated with various foods is estimated by a major study published in 2018 in the journal Science. In general, per gram of protein, beef and lamb have the greatest climate footprint, while plant-based foods such as beans, pulses, grains and soy appear to have the smallest effects. Somewhere in the middle is pork, ham, eggs and molluscs, including oysters and scallops.
There are averages only. The carbon footprint of beef, for example, depends on nutrition and farming systems. Certain cheeses may have a greater effect on greenhouse gases than a lamb chop. And some experts suggest that these figures may potentially underestimate the impact of farming-related deforestation.
Is there a easy option of food I can make that would reduce my footprint on the climate? For most people in affluent countries, eating less red meat and milk would usually have the greatest effect. A number of studies have concluded that by switching to a vegetarian diet, people who currently eat a meat-heavy diet could shrink their food-related footprint by one third or more. Giving up milk will further decrease those emissions. Only consuming less meat and milk will minimize pollution if you don’t want to go that far.
Bear in mind that food intake is often just a small fraction of the overall carbon footprint of a person: driving, flying, and home energy usage need often to be taken into account. Yet dietary changes are also one of the easiest ways for many individuals to mitigate their impact on the planet. It’s true that in the global climate crisis, one person alone can make just a tiny dent. Food is not even the largest contributor to global warming; much of it is caused by power , transportation and industry burning fossil fuels.
On the other side, that might begin to add up if several individuals made adjustments to their diets. If the world’s population continues to increase, to reduce deforestation, farmers and graziers would need to curb their emissions and grow more food on less land. Experts also argued that if the world’s heaviest meat eaters cut back even modestly, it would make a huge difference, helping to free up land to feed everyone else. Growing crops for humans to eat is much more successful than growing crops for animals to eat, and then converting those animals into food for humans. A 2017 UN Food and Agriculture Organization study found that , on average, one kilogram of meat needed around three kilograms of grain to be grown.
For another reason, beef and lamb have a particularly large climate footprint: the stomachs of cows and sheep contain bacteria which help them digest grass and other foods. But these bacteria make methane, which is then released (and a bit of flatulence) through burps.
A number of studies have established that poultry has a lower effect on the environment than other livestock. To turn feed into meat, modern-day chickens are bred to be extremely successful. That doesn’t mean that chicken is fine. Industrial-scale poultry practices also produce water contamination and have caused significant animal welfare issues. Chicken, however, typically generates far less emissions than beef and a little less than pork.
Will humans entirely stop eating meat? Not necessarily, however. A variety of experts have argued that abundant animals can and should still be included in a sustainable food system. After all, cows and other livestock will also be raised on pastures that would otherwise be unfit for crops, and they consume residues of crops that would otherwise be lost. They create manure that we can use as a fertiliser. And for some 1.3 billion people worldwide, animal agriculture offers livelihoods. Meat, eggs and milk provide a crucial source of nutrition in many countries when there are no good alternatives available.
That said, according to a recent study in the medical journal The Lancet, there are still millions of people around the world who actually consume even more meat than they need to for a balanced diet. New replacements of plant-based meat made from vegetables, starches, oils and synthesized proteins aim to imitate meat’s taste and texture. While the jury is still out on whether these foods are any better, they could have a smaller effect on the climate.
Advances in livestock raising, health treatment, feed quality and grazing systems are helping to reduce livestock operations’ environment footprint. There’s plenty of space to change further. By adding seaweed or other feed additives to their diet, some researchers are also trying to find out how to get cows to emit less methane. To place meat production on a more sustainable basis, these efforts will be crucial.
Wild fish also have a relatively small footprint in the atmosphere, with the fuel consumed by fishing boats being the main source of pollution. One recent study found that , on average, small, oily fish (anchovies, sardines and herring) have a lower carbon footprint than chicken or pork. Molluscs are excellent low-carbon alternatives, too.
Wild prawns and rock lobster, on the other hand, can have a greater impact than chicken or pork, since extra fuel for fishing boats is needed. All wild seafood, however, has an enormous caveat: most fisheries are fishing at their highest sustainable level, while others are being over-exploited. So there isn’t a lot of space in the world for everyone to raise their intake of wild fish.
Fish farming, especially for mussels and oysters, can be a climate-friendly choice, but it is not always so. Farmed fish may have a relatively low effect in areas like Norway that have strict environmental regulations. But factories are clearing away mangrove forests in parts of Southeast Asia to make room for shrimp farms, leading to a significant rise in pollution. And enormous amounts of methane have been produced by some fish farms in China. Promising efforts are underway to make fish farming more climate-friendly, but in many parts of the world, there is still a long way to go.
Almond, oat and soy milk all have a lower footprint of greenhouse emissions than cow’s milk does. But there are caveats to remember and trade-offs. In order to grow, almonds need a lot of water. As long as the soy is sustainably farmed, soy milk appears to be reasonably low-impact.
A vegan diet has the smallest climate footprint around, if you’re interested in taking the plunge. You can go vegetarian: no meat, no poultry, no fish, no milk and no eggs allowed. The rules are plain, and to accommodate vegetarians, food producers and restaurants are used. It can be a good compromise to incorporate seafood to a vegetarian diet.
Try cutting down to one serving of red meat a week to keep some meat in your diet, substituting chicken, pork, fish or plant protein for the rest. Overall, what you consume is much more important than where it comes from, as transportation accounts for just about six percent of the overall climate footprint of food. That said, a few aspects have to be considered. Anything you live in during the season, whether you buy it at a small market for farmers or at a supermarket, is typically a good option.
When it comes to out-of-season produce, things get trickier. A shockingly strong carbon footprint can be found in some perishable fruit and vegetables transported by plane. That may include asparagus or blackberries during the winter. By comparison, onions and garlic, which are more fuel-efficient, are mostly transported by boat.
In certain situations, however, food that’s flown in from abroad may have an benefit. It might be cheaper to purchase a tomato shipped in from elsewhere during the winter than to purchase a local variety grown in an energy-intensive heated greenhouse.
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