Eat Well, Save the Planet

How to shop, cook and eat in a warming world

How our daily diet contributes to global warming – and what we can do about it.

Does what I eat have an effect on climate change?

Yes. The world’s food system is responsible for about one-quarter of the planet-warming greenhouse gases that humans generate each year. That includes raising and harvesting all the plants, animals and animal products we eat – beef, chicken, fish, milk, lentils, rice and more – as well as processing, packaging and shipping food to markets all over the world.

How does food contribute to global warming?

When forests are cleared to make room for farms and livestock, large stores of carbon are released into the atmosphere, which heats up the planet. When cows, sheep and goats digest their food, they burp up methane, another potent greenhouse gas. Animal manure and rice paddies are also big methane sources. Finally, fossil fuels are used to operate farm machinery, make fertiliser and ship food globally, all of which generate emissions.

Which foods have the largest impact?

Meat and dairy, particularly from cows, have an outsize impact, with livestock accounting for around 14.5 per cent of the world’s greenhouse gases each year. That’s roughly the same amount as the emissions from all the cars, trucks, planes and ships combined in the world today.

A major study published in 2018 in the journal Science calculated the average greenhouse gas emissions associated with different foods. In general, beef and lamb have the biggest climate footprint per gram of protein, while plant-based foods such as beans, pulses, grains and soy tend to have the smallest impact. Pork, chicken, eggs and molluscs like oysters and scallops are somewhere in the middle.

These are only averages. For example, the carbon footprint of beef depends on diet and farming systems. Certain cheeses can have a larger greenhouse gas impact than a lamb chop. And some experts think these numbers may actually underestimate the impact of deforestation associated with farming.

Is there a simple food choice I can make that would reduce my climate footprint?

Consuming less red meat and dairy will typically have the biggest impact for most people in wealthy countries. A number of

studies have concluded that people who currently eat a meat-heavy diet could shrink their food-related footprint by one-third or more by moving to a vegetarian diet. Giving up dairy would reduce those emissions even further. If you don’t want to go that far, just eating less meat and dairy can reduce emissions.

Keep in mind that food consumption is often only a small fraction of a person’s total carbon footprint: there’s also driving, flying and home-energy use to consider. But dietary changes are often one of the quickest ways for many people to lighten their impact on the planet.

I’m just one person! Can I really make a difference all by myself?

It’s true that one person alone can make only a tiny dent in the global climate problem. Food isn’t even the biggest contributor to global warming; most of it is caused by burning fossil fuels for electricity, transportation and industry.

On the other hand, if many people made changes to their diets, that could start to add up. As the world’s population keeps growing, farmers and graziers will need to curb their emissions and grow more food on less land to limit deforestation. Experts have argued that it would make a big difference if the world’s heaviest meat eaters scaled back even moderately, helping to free up land to feed everyone else.

Why does meat have such a big climate impact?

It’s often more efficient to grow crops for humans to eat than it is to grow crops for animals to eat and then turn those animals into food for humans. A 2017 study by the UN Food and Agriculture Organization found that, on average, it takes about three kilograms of grain to raise one kilogram of meat.

Beef and lamb have an especially large climate footprint for another reason: the stomachs of cows and sheep contain bacteria that help them digest grass and other foods. But those bacteria create methane, that is then released through burps (and a bit of flatulence).

What about chicken?

A number of studies have found that poultry have a lesser climate impact than other livestock. Modern- day

chickens are bred to be extremely efficient at converting feed into meat. That’s not to say chicken is perfect. Industrial-scale poultry operations still create water pollution and have prompted major concerns about animal welfare. But chicken usually produces far fewer emissions than beef and a bit fewer than pork.

Should humans stop eating meat altogether?

Not necessarily. A number of experts have argued that a sustainable food system can and should still include plenty of animals. Cows and other livestock, after all, can often be raised on pasture that would otherwise be unsuitable for growing crops, and they eat crop residues that would otherwise go to waste. They produce manure that we can use as fertiliser. And animal agriculture provides livelihoods for some 1.3 billion people worldwide. In many countries, meat, eggs and milk offer a vital source of nutrition when there aren’t good alternatives available.

That said, there are also millions of people around the world who currently eat far more meat than they need to for a healthy diet, according to a recent report in the medical journal The Lancet.

What about ‘fake meat’?

New plant-based meat substitutes made from vegetables, starches, oils and synthesised proteins attempt to mimic the taste and texture of meat. While the jury is still out on whether these products are any healthier, they may have a smaller environmental footprint.

Are there other ways meat could become more climate-friendly?

Yes. Advances in animal breeding, veterinary care, feed quality and grazing systems are helping to shrink the climate footprint of livestock operations.

There’s a lot of room for further improvement. Some scientists are even trying to figure out how to get cows to emit less methane by introducing seaweed or other feed additives to their diet.

These efforts will be critical for putting meat production on a more sustainable footing.

What kinds of seafood should I eat?

Wild fish often have a relatively small climate footprint, with the main source of emissions being the fuel burned by fishing boats. One recent analysis found that small, oily fish – anchovies, sardines and herring – have, on average, a lower carbon footprint than chicken or pork. Molluscs are also great low-carbon choices.

On the other hand, wild prawns and rock lobster can have a larger impact than chicken or pork, because pulling them in demands extra fuel for the fishing boats.

There is a huge caveat to all wild seafood, though: most fisheries are being fished at their maximum sustainable level, while others are being overexploited. So there’s not a lot of room for everyone in the world to increase their wild fish consumption.

Is farmed seafood a good long-term plan?

Fish farming can be a climate-friendly option, particularly for mussels and oysters, but it isn’t always.

In places like Norway that have tight environmental regulations, farmed fish can have a relatively low impact. But in parts of Southeast Asia, producers are clearing away mangrove forests to make way for shrimp farms, which leads to a big increase in emissions. And some fish farms in China have produced enormous quantities of methane. There are promising efforts underway to make fish farming more climate-friendly, but there’s still a long way to go in many parts of the world.

What’s the impact of dairy products on climate change?

A number of studies have found that milk typically has a smaller climate footprint than chicken, eggs or pork per kilogram. Yoghurt, cottage cheese and cream cheese are similar to milk.

But many other types of cheese, such as cheddar, or other hard cheeses can have a significantly bigger footprint than chicken or pork, since it typically takes about four kilograms of milk to make 500 grams of cheese. If you decide to go vegetarian by, say, eating cheese instead of chicken, your carbon footprint might not fall as much as you expect.

Which non-dairy milk is best?

Almond, oat and soy milk all have a smaller greenhouse gas footprint than cow’s milk does. But there are caveats and trade-offs to consider. Almonds require a lot of water to grow. Soy milk tends to be fairly low-impact, as long as the soy is sustainably farmed.

So are you saying I should become a vegan?

If you’re interested in taking the plunge, a vegan diet does have the smallest climate footprint around.

I don’t think I can go vegan. What else can I try?

You could go vegetarian: no meat, poultry and fish, but dairy and eggs are allowed. The rules are simple, and food manufacturers and restaurants are used to accommodating vegetarians. Adding seafood to a vegetarian diet can be a good compromise.

To keep some meat in your diet, try cutting back to one serving of red meat per week, replacing the rest with chicken, pork, fish or plant proteins.

Should I worry about whether my produce is local and seasonal?

In general, what you eat matters a lot more than where it comes from, since transportation accounts for only about six per cent of food’s total climate footprint. That said, there are a few things to consider. Anything that’s in season where you live, whether you buy it at a local farmers’ market or at a supermarket, is usually a good choice.

Things get trickier when it comes to out-of-season produce. Some perishable fruit and vegetables that are shipped by plane can have a surprisingly hefty carbon footprint. During the winter, that may include asparagus or blackberries. By contrast, onions and garlic are often shipped by sea, which is more fuel-efficient.

In some cases, though, there can be an advantage to food that ’s shipped in from elsewhere. During the winter, it can be better to buy a tomato shipped in from elsewhere than to buy a local variety that was grown in an energy-intensive heated greenhouse.