Explainer
Agriculture — Especially Cattle Feed — Uses Most of Earth’s Freshwater
Climate•7 min read
Explainer
Eating less meat is one of the most straightforward approaches, but it’s also harder to implement.
Words by Seth Millstein
In an unexpected but no-less-depressing development, NASA has announced that 2024 was the hottest year on record. This wasn’t an anomaly, as every one of the past 10 years has been one of the 10 hottest years in the planet’s history. Climate change is a serious problem in need of a serious solution — but what counts as a viable climate solution, and what doesn’t?
It’s not an easy question to answer. In fact, you might even say it doesn’t have an answer, at least not a single one. While there is certainly widespread agreement about the need to decarbonize, there is also an ongoing debate among climate scientists about which solutions to prioritize and when. That debate is important, as there’s no single “silver bullet” for bringing down global temperatures, so we have to have these difficult conversations.
“This is pretty hard, right?,” University of Hawaii Oceanography Professor David Ho tells Sentient. “If we’re talking about carbon dioxide removal, basically, you’re talking about the largest thing that humanity has ever done.”
This illustrates the enormity of the task at hand. It’s the “largest thing humanity has ever done” — and Ho isn’t even talking about reducing our emissions across the board. He’s merely talking about carbon dioxide removal, which as we’ll see, is just one element.
Although there’s disagreement around how best to fight climate change, the contours of these disagreements are illuminating, because they’re often about deeper divides and tough decisions.
First, let’s talk about basic definitions. When we talk about climate change, we’re usually talking about rising global temperatures. Greenhouse gases — primarily carbon dioxide, methane and nitrous oxide — are the main reason temperatures are rising.
That’s why Amanda Smith, senior scientist at the climate organization Project Drawdown, argued in a 2024 webinar that any climate change solution must, by definition, reduce the concentration of greenhouse gases in the atmosphere.
This can be accomplished in two ways: by reducing the amount of carbon dioxide we emit in the first place, and by trapping and storing carbon dioxide that’s already been emitted. The first approach is commonly referred to as decarbonization, while the second is known as either carbon capture or carbon removal, depending on the method used.
Here’s where things get trickier. Although many burgeoning climate technologies and innovations have potential, Smith argues that only the ones that can effectively be deployed now can truly be considered solutions. High costs, logistical burdens, legal hurdles and other obstacles mean that many potential solutions aren’t yet ready for prime time.
Smith also argues that a climate solution isn’t much of a solution if it simply offloads carbon emissions to another sector — or causes other environmental damage that isn’t strictly emissions-related, like freshwater pollution. Or, if you advocate for better treatment of farm animals, you might argue that just switching from beef to chicken isn’t a great solution either, because it increases suffering for billions of chickens.
Humanity is facing some tough choices, Ho says. In his opinion, it’s not necessarily a dealbreaker for a climate solution to cause some collateral damage to the environment, so long as the net environmental impact is positive. Climate change will eventually render our planet unlivable if left unchecked, and so we can’t afford to reject effective solutions just because they have negative side effects that, in the grand scheme of things, are less consequential than the consequences of doing nothing.
“It’s the whole trolley problem thing,” Ho says, referring to the philosophical thought experiment that poses a quandary about whether it’s worth diverting a trolley to save five people at the expense of one. “Climate change is going to affect a lot of organisms. If we deploy a solution and it negatively affects, you know, one whale, versus if climate change kills 10 whales, which one do we choose?”
Climate research suggests there is no way to stave off the worst of global warming without addressing food-related emissions. Our global food system is responsible for around a third of all greenhouse gas emissions, and most of that third is fueled by the meat we eat, especially from cows.
The vast majority of meat comes from factory farms. But to be clear, all kinds of meat production, whether industrial or small-scale, have a negative impact on the environment. Even so-called extensive farming operations, like regenerative or organic, that tout better treatment of animals and reduced use of synthetic chemicals, exact an unavoidable climate cost in the form of enormous land usage — at least, if we’re talking about beef.
Although all types of meat production pollute the environment to some degree, beef is responsible for the largest climate impact, and there are two big reasons why.
First, there’s the removal of trees (and other uncultivated landscapes like peat bogs) that are staving off the impacts of climate change. Agricultural expansion is the culprit behind 90 percent of deforestation, and beef farming in particular is the leading driver of deforestation worldwide.
When trees are removed and peat bogs are drained, the carbon dioxide that’s so helpfully trapped there is released back into the atmosphere. Worse than that, we also miss out on the climate protection these landscapes would have provided for well into the future, something scientists call the “carbon opportunity cost.”
The biology of the cows themselves is the other factor here, as they are a huge contributor to factory farms’ climate pollution. Cows’ burps, farts and waste all emit methane, one of the most potent greenhouse gasses there is, and so cattle ranches and dairy farms continually release massive amounts of greenhouse gases into the air on a daily basis.
On a more positive note, the flip side of this is also true. Tackling methane emissions, whether by fixing gas leaks or eating less meat, is an opportunity to curb climate pollution quickly.
There is plenty of agreement about many of the broad strokes of climate action — curbing dependence on fossil fuels, the need to electrify the grid and even the benefit of plant-forward sustainable diets, for instance. Yet there is also debate about what the path to a better future should look like.
Some favor modest changes to existing systems, whereas others insist on full-scale reform, or even abolition, of those systems. Some focus squarely on one high-emissions sector — for instance, agriculture or fossil fuels — while others support what Smith calls a “tapestry” of solutions across many industries. There are also fierce debates about the role of technology, whether the solution is cultivated meat, nuclear energy or carbon storage pipelines.
Let’s take a look at the debates over a few proposed climate solutions, as each illuminates a deeper philosophical divide.
As mentioned earlier, there are two ways to bring down the concentration of CO2 in the atmosphere: reducing emissions at the source, or removing CO2 that’s already been emitted. Both approaches are necessary if we want to eventually reach net-zero carbon emissions, because some emissions — such as those from airplanes — will never be eliminated entirely.
A lot of companies have invested heavily in technology that removes carbon dioxide from the air. That’s one of the upsides to carbon removal as a strategy: it has a lot of buy-in and money behind it, including from major polluters like Exxon. This is largely because it doesn’t require them to actually reduce their carbon emissions.
The various methods we have for trapping carbon from the atmosphere don’t do so nearly fast enough to compensate for the amount of carbon we emit on a daily basis. It’s like using a teaspoon to empty out a boat that’s rapidly filling up with water: it won’t work.
For this reason, Ho argues, we first need to dramatically reduce how much carbon we emit before deploying technology to remove it from the air.
“It will always cost more energy to do the removal than to not emit it in the first place,” Ho tells Sentient. “So we really should concentrate our energy on decarbonization, and not putting the CO2 into the atmosphere [in the first place].”
Digesters are essentially large, oxygen-free containers that take organic waste, like animal manure, and turn it into something else, kind of. The digester, or reactor, contains microbial communities that are specifically designed to break down the manure and convert its emissions into biofuel. This fuel can then be used by cars and other vehicles.
The dairy industry has been a particularly vocal proponent of digesters, which received millions in funding from the Biden administration through the Inflation Reduction Act. Much like carbon removal technology, digesters have buy-in from polluting industries like pork, dairy, oil and gas, and don’t require any large-scale change to how these industries function.
But in practice, digesters come with plenty of downsides that cast doubt on their efficacy.
To begin with, the biofuels digesters create are still a form of gas. They still emit carbon when they’re burned. As such, many environmentalists argue that producing them perpetuates our reliance on gas-powered vehicles, and forestalls a transition to zero-emission electric vehicles, and away from factory farms.
Due to their expense, digesters are only practical for use on the largest factory farms, and they rely on the continued use of manure lagoons, which have a host of negative environmental and social impacts themselves.
Rebecca Wolf, a senior food policy analyst at the nonprofit Food & Water Watch, argues against digesters and biofuels on the grounds that they allow the factory farm system itself to continue chugging along without meaningful reform, while continuing to emit significant amounts of greenhouse gasses.
“They require factory farms to continue to produce large amounts of waste,” Wolf tells Sentient. “And so they’re perfect to put on top of a factory farm, and then keep that waste stream going.”
Digesters, Wolf says, “bring together Big Oil and Big Ag,” as they allow both industries to “greenwash their waste products” while continuing to emit prolific amounts of greenhouse gases.
Feed additives are similar to digesters in that they’re designed to reduce methane emissions on animal farms. But while digesters do this by capturing methane that’s emitted from animal waste, feed additives reduce the amount of methane animals emit in the first place by altering the way their bodies digest food.
Although most feed additives haven’t yet been subject to rigorous testing, one exception is a compound known as 3-NOP. Studies of 3-NOP suggest that it could reduce enteric methane emissions by as much as 32.5 percent.
In order to work, animals need to eat feed additives every day; this works for cattle who are fed concentrates, but for those that feed via grazing, ensuring that each of them eat enough additives every day is a logistical nightmare.
Moreover, these additives aren’t cheap. While fighting climate change benefits all of humanity in the long run, buying expensive feed additives doesn’t benefit individual farmers in the short run; it hurts their bottom line, and this is a major obstacle to the widespread adoption of feed additives.
Lastly, because most feed additives haven’t yet been sufficiently studied, it’s unclear what other effects they might have on animals or humans. There’s even some research that 3-NOP, ostensibly one of the most promising feed additives, actually increases carbon dioxide emissions.
“Animal agriculture has a lot of negative environmental impacts,” Ho tells Sentient. “It’s not just the CO2 emissions. If you feed some seaweed to cows, you’re still going to get the other negative environmental impacts. Those aren’t going away, and so it does seem like we should do something that will reduce all of those impacts, not just the CO2 or the methane.”
There’s an elephant in the room when we talk about animal agriculture as a driver of climate change: our appetite for animal products. Per-capita meat and dairy consumption have been steadily rising over the decades, and with it, our reliance on factory farms as a food source. Climate “solutions” like feed additives and digesters do nothing to stem this appetite. In fact, they seem to help entrench our current food system even further.
Many climate research groups, like World Resources Institute and Project Drawdown, have pointed out that if global north countries simply ate less meat, especially beef, this would make a huge dent in the climate problem. In practical terms, such a reduction would have to take place primarily in middle- and upper-income countries, which consume a disproportionate amount of meat on a per-capita basis.
“The choice of what people eat matters a lot,” Ho says. “If we stop eating beef and cut down on dairy, or just cut out dairy altogether, that would make a huge difference.”
Ho is optimistic about cultivated meat as a potential climate solution. The prospect of being able to create real meat in a laboratory without needing to clear away land, house, feed and slaughter millions of animals is an incredibly appealing proposition in the fight to bring down carbon emissions and reduce global temperatures.
Cultivated meat technology is still in its infancy, though. As it stands, it’s still much too expensive to scale; this means it can’t be deployed now, which means it doesn’t yet meet Smith’s criteria for a climate solution.
Just as significantly, cultivated meat — and any climate solution that entails people replacing traditional meat in their diet — faces cultural hurdles. Many people, including some powerful elected officials, are skeptical of meat that’s created in a laboratory, and in the U.S., some Republican governors have even signed laws banning its sale within their states.
But Ho is supportive of the technology, which may well become more affordable and practical as future research brings down its production costs.
“I know that some people are not really into cultivated meat, but I would get more excited about that than like, reducing methane emissions from cows,” Ho tells Sentient. “It also deals with the animal suffering part of it, which I think is huge.”
There are contentious debates happening around climate action — how much should we invest in technologies, versus fundamentally remaking the way we produce things — especially food. There are deep divides, yet there is also a lot of agreement on simpler strategies, like eating less meat and more beans; a diet that remains healthier for the planet and its inhabitants, animals and people alike.