Global livestock emissions should peak by 2030 or sooner to meet the Paris climate agreement target of limiting the global temperature increase to 1.5 degrees Celsius, the surveyed climate experts said. In high- and middle-income countries, which produce and consume the overwhelming majority of the global meat and dairy supply, livestock emissions should peak much earlier than in low-income countries.
“We need to see major changes in livestock production and consumption — really deep and rapid changes over the next decade,” said Helen Harwatt, an environmental social scientist and lead author of the survey report, which was published last week by Harvard’s animal law and policy program, where Harwatt is a fellow. The survey was also co-authored by researchers Matthew Hayek, Paul Behrens, and William Ripple.
Asked how rapidly global livestock emissions should fall after they peak, the experts’ most common response was a 50 percent or more decrease within five years after peaking. And the most effective way to do that, most survey respondents agreed, is by reducing the amount of meat and dairy humanity produces and consumes.
But such a peak, let alone a swift reduction in the amount of meat we eat, is nowhere in sight. Rising global meat consumption, along with vanishingly little government policy designed to change diets or cut pollution from factory farms, means we’re all but guaranteed to miss even the least ambitious targets suggested by climate and agricultural scientists in the Harvard survey.
Last year, a United Nations and OECD analysis predicted global meat consumption — a good but imperfect proxy for livestock emissions — won’t actually peak until 2075.
Livestock emissions are primarily generated by cows’ methane-rich burps, animal manure, and the corn and soy produced to feed farmed animals. Globally, the sector accounts for around 15 to 20 percent of greenhouse gas emissions and is the leading driver of deforestation, which further exacerbates climate change.
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But animal agriculture has largely evaded environmental regulation, and only 12 of the 175 countries that have signed on to the Paris climate agreement have committed to reduce livestock emissions.
Nearly two decades ago, a United Nations report marked the livestock sector as one of the most polluting industries on the planet. Ever since, there’s been a steady drip of research on the need to scale back meat production in high- and middle-income countries.
Industry is fighting back. A well-oiled PR machine composed of shadowy communications groups, industry-funded academics, and pro-meat influencers all push out the message that livestock aren’t so bad for the planet. Their claims have ranged from misleading scientific arguments to hollow corporate greenwashing to outright disinformation.
Harwatt’s survey cuts through all this noise, revealing a consensus among climate scientists that the annual slaughter of around 80 billion land animals for food is simply unsustainable.
How to slash meat’s carbon footprint: produce a lot less of it
As pressure increases for the livestock industries to reduce emissions, companies and governments have announced a slate of technologies and farming practices they claim will help reduce meat and dairy’s carbon footprint. This includes things like improving manure management, changing animals’ diets and genetics, and “regenerative agriculture,” a type of farming that aims to sequester and store carbon dioxide from the atmosphere inside the soil.
But according to the new survey’s respondents, these industry-touted practices won’t do nearly as much to cut pollution from cow burps and chicken poop as raising and eating fewer animals.
Around three-quarters of respondents said reducing livestock production and consumption would make a large or very large contribution to shrinking the livestock sector’s carbon footprint. Less than half of respondents said the same about the practices often promoted by industry.
“We need to drastically reduce livestock numbers, particularly in high- and middle-income countries — the evidence shows that clearly,” said Pete Smith, a survey respondent and climate scientist at the University of Aberdeen in Scotland. Smith is an authority on the issue, acting as a lead author on United Nations environmental reports for over two decades.
Almost half the survey respondents said that replacing beef with lower-emissions meats like pork, poultry, and farmed fish would make a large or very large contribution to emissions reduction. But Smith warns against this because raising those species still requires a significant amount of farmland to grow corn and soy to feed them. In other words, they’re still far more carbon-intensive than plant-based foods.
“They’re eating products that are grown on land that could be growing food for humans instead, so it’s still a really inefficient thing to do to swap out ruminant [beef, lamb, goat] products for other different types of meat,” Smith said.
It would be far better for the environment and animal welfare to transition to growing “plant-based products that can be consumed directly by humans,” he said. “I think that’s got to be the way forward. And that’s the one that will free up the most land that will allow us to create the carbon sinks that we need.”
One survey question asked how our diets would need to change if the livestock sector were required to reduce emissions to align with the 2015 Paris climate agreement. Participants answered on a sliding scale, with minus five meaning a more animal-based diet, zero meaning maintaining current diets, and five meaning more plant-based diets.
On average globally, respondents said, we’d need to adopt a diet much richer in plant-based foods. But scientific consensus is often no match for politics.
Navigating the politics of meat
In the US, there’s been no legislation passed to meaningfully reduce livestock emissions, as industry has lobbied hard against proposed regulations. European policymakers seeking to regulate animal agriculture have been met with fierce opposition. In the Netherlands, farmers have jammed up highways with tractors and set fire to hay bales in protest of new limits on livestock pollution.
“As we have seen by the recent protests in Europe, it’s really becoming a left/right, or a liberal/conservative dividing line,” said Lukas Fesenfeld, a researcher at ETH Zurich and lecturer at the University of Bern who studies environmental and food policy. Fesenfeld did not participate in the survey.
Fesenfeld said it’s also a political economy issue, meaning that there aren’t many actors who would benefit economically from a radical reduction in livestock numbers. Meanwhile, the powerful meat lobby has a strong interest in maintaining the status quo. There’s also the personal element: People like meat, and government policy designed to reduce its supply would be highly unpopular.
A solution, Fesenfeld said, is to implement policy in a certain sequence — first carrots, then sticks — that could help reduce political blowback and ensure a more just transition.
First, governments could fund research and development to make meat and dairy alternatives taste better and become more affordable, while supporting farmers growing crops for a more plant-based food supply chain. Denmark, Germany, and other countries are experimenting with such policies.
Second, there’s a lot the public sector could do to change the food environment to be more climate-friendly. For example, buying more plant-based meals with government dollars — like at schools and hospitals — and working with restaurants, grocers, and cafeterias to offer more plant-based options (and better market them).
Over the last two years, for example, New York City’s hospital system served 1.2 million plant-based meals, which it says reduced its food carbon footprint by 36 percent in 2023, saved money, and had high reported satisfaction from patients.
These two approaches could eventually make more aggressive policies, like reducing agricultural subsidies for livestock production or making large meat companies pay for excessive pollution, more politically digestible.
“It’s a really challenging thing, actually, for policymakers and the industry to think about the kind of depth and pace of the reductions that the experts are saying are needed,” Harwatt said. But after decades of inaction, we’re left with two options: aggressive policy to achieve that required depth and pace of reductions, or a dire level of global warming.
