Your Questions About Food and Climate Change, Answered – The New York Times

Your diet affects climate change. Here’s what you need to know about eating meat, dairy, seafood and produce, and preventing food waste.
Meat and dairy, particularly from cows, have an outsize impact, with livestock accounting for around 14.5 percent of the world’s greenhouse gases each year. That’s roughly the same amount as the emissions from all the cars, trucks, airplanes and ships combined in the world today.
In general, beef and lamb have the biggest climate footprint per gram of protein, while plant-based foods tend to have the smallest impact. Pork and chicken are somewhere in the middle.
Holy Cow!
The average greenhouse gas impact (in kilograms of CO2) of getting 50 grams of protein from:
Beef
17.7
 
Lamb
9.9
Farmed
crustaceans
9.1
Cheese
5.4
Pork
3.8
Farmed fish
3.0
Poultry
2.9
Eggs
2.1
Tofu
1.0
Beans
0.4
Nuts
0.1
Beef
17.7
 
Lamb
9.9
Farmed
crustaceans
9.1
Cheese
5.4
Pork
3.8
Farmed fish
3.0
Poultry
2.9
Eggs
2.1
Tofu
1.0
Beans
0.4
Nuts
0.1
Beef
17.7
 
Lamb
9.9
Farmed
crustaceans
9.1
Cheese
5.4
Pork
3.8
Farmed fish
3.0
Poultry
2.9
Eggs
2.1
Tofu
1.0
Beans
0.4
Nuts
0.1
Beef
17.7
 
Lamb
Farmed
crustaceans
9.9
9.1
Cheese
5.4
Pork
3.8
Farmed fish
3.0
Poultry
2.9
Eggs
2.1
Tofu
1.0
Beans
0.4
Nuts
0.1
Beef
17.7
 
Lamb
Farmed
crustaceans
9.9
9.1
Cheese
5.4
Pork
3.8
Farmed fish
3.0
Poultry
2.9
Eggs
2.1
Tofu
1.0
Beans
0.4
Nuts
0.1
Now, these are only averages. Beef raised in the United States generally produces fewer emissions than beef raised in Brazil or Argentina. 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 and ranching.
But most studies agree that plant-based foods usually have a lower impact than meat, and beef and lamb tend to be the worst offenders by a considerable margin.
Consuming less red meat and dairy will typically have the biggest impact for most people in wealthy countries. That doesn’t necessarily mean going vegan. You might just eat less of the foods with the biggest climate footprints, like beef, lamb and cheese.
It varies from person to person. A number of studies have concluded that people who eat a meat-heavy diet — including much of the population of the United States and Europe — could shrink their food-related footprint by one-third or more by moving to a vegetarian diet. Giving up dairy would further reduce those emissions. But even eating more plants, and less dairy and meat, particularly red meat, can help: According to a World Resources Institute analysis, if the average American replaced a third of the beef he or she eats with pork, poultry or legumes, his or her food-related emissions would still fall by around 13 percent.
Still, food consumption is often only a small fraction of a person’s total carbon footprint. And, ultimately, the most important thing we can all do is vote, as policy changes have an enormous impact. But dietary changes are often one of the quickest ways for many people to lighten their climate impact, and if many people collectively made these changes, it could start to add up.
Think about it this way: 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.
In their defense, cows, chickens and pigs often eat a lot of things that humans wouldn’t otherwise eat, like grasses or crop residues, and meat can be rich in key nutrients like protein and iron. But, in general, it takes more land, energy and water to produce a pound of animal protein than it does to produce a pound of plant protein.
It’s hard to say with confidence that grass-fed beef is consistently more climate-friendly than conventional beef.
Some scientists have suggested that grass-fed beef, if managed properly, can be a more sustainable option: As the cattle graze, they stimulate grass to grow deep roots and pull more carbon into the soil, helping to offset their climate impact. But, on the flip side, grass-fed cattle also take longer to reach slaughter weight, which means they spend more time burping up methane into the atmosphere. Because of this, some studies have suggested that grass-fed beef can actually be worse for the climate over all, though the debate about this continues.
A number of studies have found that chicken and other poultry have less of a climate impact than other livestock. 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 if you’re solely focused on climate change, chicken usually produces far fewer emissions than beef and a bit fewer than pork.
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 also produce manure that we can use as fertilizer. 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 — in places like the United States, Europe and Australia — who eat far more meat than they need to for a healthy diet, according to a 2019 report in the medical journal The Lancet. And if we want to feed a growing population without adding to global warming or putting increased pressure on the world’s forests, it would make a difference if the heaviest meat eaters cut back.
Plant-based meat substitutes are increasingly showing up in supermarkets and even fast-food chains. Made from vegetables, starches, oils and synthesized proteins, these products attempt to mimic the taste and texture of meat more closely than traditional substitutes like tofu and seitan.
While the jury is still out on whether these products are any healthier, they do appear to have a smaller environmental footprint: One 2018 study estimated that a Beyond Burger had just one-tenth the climate impact of a beef burger.
In the future, researchers may be able to “grow” real meat from animal cell cultures — work is continuing on this front. But it’s too early to say how helpful this will be from a climate perspective, not least because it could take a lot of energy to produce cell-cultured meat.
Yes. If meat production around the world were to become more efficient, farmers and ranchers would be able to feed more people while reducing their emissions.
This is already happening in many places: The United States, for example, produces more beef today than it did in 1975 even though the total number of cattle has declined by about one-third. Advances in animal breeding, veterinary care, feed quality and grazing systems are already helping to shrink the climate footprint of livestock operations around the world, and 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.
Since it’s unlikely that the whole world is going to go vegetarian anytime soon, these efforts will be critical for putting meat production on a more sustainable footing.
Wild fish often have a relatively small climate footprint, with the main source of emissions being the fuel burned by fishing boats. A 2018 analysis found that a number of popular wild fish — anchovies, sardines, herring, tuna, pollock, cod, haddock — have, on average, a lower carbon footprint than chicken or pork. Mollusks like clams, oysters and scallops are also great low-carbon choices. (We have dozens of good recipe options for you here.)
On the other hand, wild shrimp and 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: At this point, the world is already catching about as much as it possibly can — most fisheries are being fished at their maximum sustainable level, while others are being overexploited. So there’s not a ton of room for everyone in the world to increase their wild fish consumption. (If we are going to eat more seafood in the coming decades, most of that increase will probably come from fish farms, also known as aquaculture.) For now, you can check with science-based sources like Seafood Watch to see if the fish you buy is being harvested sustainably.
Fish farming can sometimes be a climate-friendly option, particularly for mollusks, but it isn’t always. It often depends on farming practices and geography.
In places like Norway that have tight environmental regulations, farmed fish can have 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 plenty of promising efforts underway to clean up fish farming and make it more climate-friendly, but there’s still a long way to go in many parts of the world.
A number of groups, like the Aquaculture Stewardship Council and Friend of the Sea, are starting to certify fish farms that adhere to environmental standards and can be a good starting point. But a note: Critics have warned that these labels often don’t account for the full climate impacts of farmed seafood.
Still, a recent study found some general trends: Farmed mollusks (oysters, mussels, scallops) tend to be protein options with some of the lowest emissions around, and farmed salmon has, on average, a lower impact than chicken or pork.
On the other hand, farms for catfish and shrimp often require a large amount of energy to recirculate water and can sometimes have a larger climate footprint than even beef. But there’s a lot of variation from farm to farm.
You could incorporate more mollusks into your diet. Most Americans don’t often eat them at home, but mussels, clams and scallops are familiar, succulent and easier to cook than you might think. We have recipes for you right here.
As for farmed or wild fish, they can often be a good low-carbon option, but it’s a good idea to check first whether a product is certified as sustainable.
A number of studies have found that milk typically has a smaller climate footprint than chicken, eggs or pork per pound. Yogurt, cottage cheese and cream cheese are similar to milk.
But many other types of cheese, such as Cheddar or mozzarella, can have a significantly bigger footprint than chicken or pork, since it typically takes about 10 pounds of milk to make one pound of cheese.
It depends on the cheese. But broadly speaking, yes, if you decide to go vegetarian by, say, eating cheese instead of chicken, your carbon footprint might not fall as much as you expect.
The short answer is that you can’t count on organic milk being better for the climate.
To date, studies have disagreed on whether organic dairy farms produce more, less or about the same amount of greenhouse gas emissions as conventional farms do, per gallon of milk. Most likely, it varies a lot from farm to farm. The trouble is that there’s nothing about the organic label that tells you anything specific about the climate impact of the carton of milk you’re holding.
Almond, oat and soy milk all have a smaller greenhouse gas footprint than cow’s milk does. But, as always, there are caveats and trade-offs to consider. Almonds require a lot of water to grow, and this has been a problem in places like California. Soy milk tends to be fairly low-impact, as long as the soy is sustainably farmed.
Milk vs. ‘Milk’
Environmental impacts of different types of milk, per liter.
Emissions (kilograms CO2)
Land Use (square meters)
Water Use (liters)
Cow
3.2
9.0
628
Rice
1.2
0.3
270
Soy
1.0
0.7
28
Oat
0.9
0.8
48
Almond
0.7
0.5
371
Emissions (kilograms CO2)
Land Use (square meters)
Water Use (liters)
Cow
3.2
9.0
628
Rice
1.2
0.3
270
Soy
1.0
0.7
28
Oat
0.9
0.8
48
Almond
0.7
0.5
371
Emissions
(kilograms CO2)
Land Use
(square meters)
Water Use
(liters)
Cow
3.2
9.0
628
Rice
1.2
0.3
270
Soy
0.7
1.0
28
Oat
0.9
0.8
48
Almond
0.7
0.5
371
Emissions
(kg CO2
Water Use
(liters)
Land Use
(meters2)
Cow
3.2
9.0
628
Rice
1.2
0.3
270
Soy
1.0
0.7
28
Oat
0.9
0.8
48
Almond
0.7
0.5
371
Emissions
(kg CO2
Land Use
(meters2)
Water Use
(liters)
Cow
3.2
9.0
628
Rice
1.2
0.3
270
Soy
1.0
0.7
28
Oat
0.9
0.8
48
Almond
0.7
0.5
371
If you’re interested in taking the plunge, a vegan diet does have the smallest climate footprint around.
If you like pasta with tomato sauce, hummus, avocado toast or peanut butter and jelly sandwiches, you actually do like some vegan food. Eating a fully vegan diet is hard for many Americans to imagine. Some assume that a vegan diet has to include meat “substitutes” like tofu, but that’s not true: There’s ample protein in beans, grains and nuts. And as more people become vegan, plant versions of ice cream, butter and even burgers are getting better all the time. For home cooks, the challenge is often producing a vegan dinner that everyone at the table will eat. We’ve got recipes that can help.
Another approach would be to simply eat less meat and dairy, and more protein-rich plants like beans, legumes, nuts and grains. (Here are recipes that go heavy on beans and grains.)
You could go vegetarian: no meat, poultry and fish, but dairy and eggs are allowed. The advantage here is that the rules are simple, and food manufacturers and restaurants are used to accommodating vegetarians. (We have vegetarian recipes for you that you can cook on a weeknight.)
Eating as a pescatarian, adding seafood to a vegetarian diet, can be a good compromise, and makes it easier to get protein into your meals.
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. This approach is more flexible, but it means more planning ahead and keeping track of what you eat.
Climate-Friendlier Diets
The average drop in food-related emissions when people switch from a typical Western diet to lower-impact ones:
–50%
-40
-30
-20
-10
0
Average
reduction
Vegan
Reduction range
Vegetarian
Partly replace meat
and dairy with plants
Replace beef and lamb
with other meat
–50%
-40
-30
-20
-10
0
Average
reduction
Vegan
Reduction range
Vegetarian
Partly replace meat
and dairy with plants
Replace beef and lamb
with other meat
–50%
-40
-30
-20
-10
0
Average
reduction
Vegan
Reduction range
Vegetarian
Partly replace meat
and dairy with plants
Replace beef and lamb
with other meat
–50%
-40
-30
-20
-10
0
Average
reduction
Vegan
Reduction range
Vegetarian
Partly replace meat
and dairy with plants
Replace beef and lamb
with other meat
–50%
-40
-30
-20
-10
0
Average
reduction
Vegan
Reduction range
Vegetarian
Partly replace meat
and dairy with plants
Replace beef and lamb
with other meat
–50%
-40
-30
-20
-10
0
Average
reduction
Vegan
Reduction range
Vegetarian
Partly replace meat
and dairy with plants
Replace beef and lamb
with other meat
Organic produce is grown without synthetic fertilizers or pesticides, which is important to a lot of people. But that doesn’t mean it’s necessarily better from a climate perspective. In some cases, it can be a bit worse: Organic farms often require more land than conventional farms. That said, organic farms’ climate impact can vary widely from place to place, and the organic label, on its own, doesn’t give you great information on the food’s carbon footprint.
In general, what you eat matters a lot more than where it comes from, since transportation accounts for only about 6 percent 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 fruits and vegetables that are shipped by plane can have a surprisingly hefty carbon footprint. During the winter, that may include asparagus or blackberries — produce that’s perishable and needs to move quickly between distant places. By contrast, apples, oranges and bananas are often shipped by sea, which is more fuel-efficient. Plenty of cold-climate vegetables, like carrots, potatoes and squash, can be stored after the fall harvest and last through the winter.
In some cases, though, there can be an advantage to food that’s shipped in from elsewhere. If you live in the northern United States during the winter, it can be better to buy a tomato trucked in from California or Florida than to buy a local variety that was grown in an energy-intensive heated greenhouse.
By some estimates, Americans end up throwing out roughly 20 percent of the food they buy. That means that all the energy it took to produce that food was wasted. If you’re buying more food than you actually eat, your climate footprint will be bigger than it needs to be.
But there are many ways to reduce waste. Start with meal planning: Take 20 minutes to lay out three weeknight dinners, so you buy only the food you plan to cook. (And don’t order more than you need, if eating out.) Trim and wash produce before putting it away, to make it easier to use. And be vigilant about eating or freezing the food in your refrigerator, instead of letting it spoil. Certain items also don’t go bad as quickly as you might think: “Sell by” labels are usually manufacturer suggestions for peak quality. Many foods (with the exception of baby formula) can still be safely consumed after that date.
Beef, lamb and cheese tend to do the most climate damage. Pork, chicken and eggs are in the middle. Plants of all kinds typically have the lowest impact.
What you eat matters a lot more than whether it’s local or organic, or what kind of bag you use to carry it home from the store.
You don’t have to give up meat altogether to make a difference. Even small shifts, like eating less meat and more plants, or switching from beef to chicken, can reduce your climate footprint.
Waste less. Buying what you need and actually eating it — instead of tossing it out — means that the energy used to produce your food has been spent efficiently.
Vegan
Vegan
Seafood
Vegan
Vegetarian
Vegan
Additional design and production by Aliza Aufrichtig.

An earlier version of this article included an incorrect citation for a scientific publication by Aleksandrowicz et al about climate-friendlier diets. The study appeared in the journal PLoS One, not PNAS, Proceedings of the National Academy of Sciences. 
An earlier version of a graphic accompanying this article about the average greenhouse gas impact of various foods included a value for milk that was based on a different measurement than the other foods. The 1.6 kilograms of CO2 impact for milk is per half-liter, not per 50 grams of protein, which is the measure used for the other foods in the chart.
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