Between a quarter and a third of all the emissions mankind is producing comes from agriculture. Despite a range of estimates, the ultimate figure seems to always be around the 25%-35% figure, but a ten percent difference in global emissions is a huge deal. So where does this difference come from, and what can we do to reduce these emissions?

Why so much greenhouse gas?

Although people are becoming increasingly aware of the environmental impact their food has, it can come as quite a shock to see just how much of our emissions are caused by our food. How is it that so much of the global emissions, with everything that’s involved, comes from agriculture? Meat alone is responsible for more emissions than all the cars and planes in the world put together, where does all that come from?

From planting a seed to having something served on a plate, our food undergoes quite the journey, and we don’t often think about everything it involves. Our food’s emissions can roughly be split into four categories:

• Land use: even before a single calorie has been consumed, deforestation and land clearing can produce emissions. The drainage and burning of soils, and the degradation of peatlands and other carbon-rich soils also contribute.
• Agricultural production: everything from fertilizer to fuel used for machines, methane from cows, burning of agricultural waste, etc.
• Packaging and distribution: food processing, packaging, transport, and retail also produces a hefty chunk of emissions.
• Cooking and waste: this part sometimes gets left out of studies, but cooking food and throwing it away can also produce substantial emissions.

Overall, this is what a breakdown of our food’s emissions would look like:

Why estimates differ

The chart above, compiled by the folks from Our World in Data, is based on a 2021 study by Crippa et al. Overall, the study found that a third of our total emissions comes from agriculture. It was a landmark study that clearly highlighted just how big of a role agriculture plays in the ongoing climate crisis, and how if we want to truly address the crisis, we need to look at more than just electric cars and renewable energy.

This was, at a basic level, not surprising at all. Previous studies have also warned that agriculture is a major contributor to emissions, and in general terms, the main takeaway message is the same. But beneath the takeaway message, why are the estimates different?

For instance, a 2018 study by Poore and Nemecek claimed that about a quarter of our emissions comes from agriculture, as opposed to a third, as per Crippa et al.

The difference between ‘a third of our emissions’ and ‘a quarter of our emissions’ may not seem like much, but it is a huge difference. That gap is four times largerthan the entire aviation industry, and about as much as India’s entire emissions. Going into the nuts and bolts of this difference may be unglamorous, but it’s what can help us better understand how to address this problem. So where do the differences come from?

For starters, Poore and Nemecek don’t always include cooking and post-consumer emissions. That alone is a big difference between the numbers, but not the only one. Poore and Nemecek only looked at food agriculture, whereas the other study also looked at non-edible agricultural products, like cotton and leather. Other differences also come from different estimates used, like for instance how much deforestation each study attributes to agriculture.

A comparison between the two studies would look like this:

So which is it? How much emissions actually come from agriculture? Well, if you include all agriculture, with not just food, it probably produces around a third of our emissions. If you don’t and only look at food, then the figure is probably somewhere over 25% — because the 26% figure of Poore and Nemecek doesn’t include post-retailer emissions. Hannah Ritchie, Head of Research at Our World In Data, sums it up thusly:

“The amount of uncertainty in these estimates means it’s helpful to understand where the differences come from, and that they all fall within a reasonably narrow range. If someone asks me, my response is usually “around 25% to 30% from food. Around one-third if we include all agricultural products.””

Meat is a problem, eating local doesn’t help much

Being aware of the problem is important, but it can only do so much. At the end of the day, we also need solutions. When it comes to reducing agriculture emissions, meat seems like the first place to strike.

An important finding of the Poore and Nemecek study is that meat’s emissions are more than just direct emissions. For instance, crops grown for animal feed amount for 6% of total food emissions, and land use for livestock amounts to 16% of total food emissions. In other words, that’s 22% of food emissions that were camouflaged under other categories. When you add it all up together, livestock and fisheries make up more than half our food’s emissions.

No matter how you look at this, this is a lot. A kilogram of beef emits 60 kilograms of greenhouse gases (CO2-equivalents) while peas, for instance, emits just 1 kilogram of gas per kg. Sure, meat can be very calorie-rich and has a lot of proteins, but it’s still disproportionate. Some meat is worse than others but, alas, alternatives fare much better environmentally.

The good, the bad, and the ugly

The world has pledged to do its best and keep the planet from heating more than 2 degrees Celsius over pre-industrial levels. Virtually all the countries on the planet have pledged to this. The bad news is that we’re really not on course to do this. If current trends continue, we’re headed for a disastrous warming.

By now, hopefully, it’s become clear that agriculture is a big part of this problem. To put it this way: we have an emissions budget, and a third of that budget goes to food and such. If we’re trying to cut expenses, it would make a lot of sense to look for cheaper food (read: less carbon-intensive food).

This is the good news: we know what needs to be done, and it’s already starting to happen. According to one recent report, Europe and the US are on track to reach “peak meat” by 2025, thanks especially to plant-based alternatives. It seems that as people pass a threshold of income and awareness, they start to shift to more plant foods — that’s great.

The ugly problem is that only a small part of the world seems to have reached that threshold, and before they do reach it, meat consumption actually grows. Simply put, the highly developed countries are starting to eat less meat; the other countries are eating more and more as they become more developed, and meat consumption grows as they become richer.

Overall, meat consumption is growing worldwide, especially in Asia.

There are, of course, other things that can be done. Reducing deforestation is one way, using fertilizers more sustainably is another. Having on-farm renewable energy and electric tractors will also help, as will paying more attention to crop rotation and sustainable agricultural practices that keep the soil healthy and prevent erosion. As consumers though, we have little control over that, other than choosing from producers who implement sustainable practices.

As consumers, the only real power we’ve got is what we choose to eat. Sometimes, carbon-intensive food is cheaper, more accessible, or takes less time to cook. Understandably, it can be easier to simply not look at this side of things. But if we want to truly address the climate crisis, this is the type of thing we need to look at.