Two new studies are making the case that people in high-income countries need to cut back on livestock-based foods, but they're also suggesting that one-size-fits-all recommendations won't work in all cases.

Though each advocates a major transformation in how the world eats and produces food in order to slow climate change—including a shift toward plant-based diets—they also say that consuming meat and dairy products in certain parts of the world, by certain populations, is critical for meeting nutritional goals.

One report explores the economic case for changing current food production and consumption habits, estimating that they cause about $12 trillion a year in damage to the environment, human health and development. If countries invested just half of 1 percent of global GDP in carbon-friendly agriculture, food waste reduction, reforestation and prescribing more plant-focused diets, among other measures, the world could sustainably feed itself and reduce the climate-related damage, the authors found.

"What over 9 billion people choose to eat and how they make these choices are at the heart of how our food and land use systems evolve," the report finds, adding: "The right animals, in the right places and raised in the right conditions can continue to play an important role in sustainable food and land use systems."

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In a second report, published Tuesday in the journal Global Environmental Change, researchers at Johns Hopkins University found that modest shifts toward plant-based diets globally could cancel out the increase in greenhouse gas emissions from helping undernourished populations get adequate nutrition, including protein. The number of malnourished people in the world—roughly 820 million—remains stubbornly high.

"So many countries are dealing with under-nourishment. They're going to have to increase food consumption, and accordingly their carbon footprints are going to have to go up," said Keeve Nachman, director of the Food Production and Public Health Program at Johns Hopkins' Center for a Livable Future and one of the report's authors. "We have a responsibility as a global community to make sure they have enough food. What that means is that high-income countries that typically consume more animal products are going to have to more rapidly consider some of these plant-forward dietary shifts."

Their study took nine different plant-focused diets and determined what the carbon impacts of each would be for 140 different countries around the world. The idea, Nachman explained, was to help policy makers in those countries understand how potential dietary shifts might impact nutritional needs and their carbon footprints.

The study comes in the wake of a series of reports, including one from the United Nations, calling for a global shift toward plant-based diets. During the negotiations on that report's language, some developing countries argued that it was unfair to call for a broad, global reduction in meat consumption when some populations still lack enough protein.

"We recognize that every country has its own complex set of situations and priorities, so we're presenting these nine plant-forward diets in the hopes that we're giving decision makers options that are benchmarked to these climate and water footprints," Nachman said. "If we come barreling in with statements about how we need to reduce animal products, that could fall on deaf ears. All countries can be part of the solution."

Different Plant-Based Diets, Different Impacts

Nachman and his colleagues analyzed common, recognizable diets including "lacto-ovo vegetarian," in which people eschew meat and fish but eat dairy and eggs; a "two-thirds" vegan diet, in which people consume one-third of their diets in animal-based protein; strictly vegan diets; and diets in which people ate mostly plant-based foods but also some proteins low on the food chain, like mollusks and small fish.

They found that a shift to vegan diets reduced per capita greenhouse gas footprints by 70 percent, having the lowest per capita carbon impact in 97 percent of the countries.

They also found that lacto-ovo vegetarian diets had a higher carbon footprint than diets in which vegans consumed meat in moderation but avoided dairy, largely because of the greenhouse gas emissions from dairy production. And they found that low-food-chain diets had less than half the greenhouse gas emissions of lacto-ovo vegetarians in more than 90 percent of the countries.

"These findings suggest populations could do far more to reduce their climate impact by eating mostly plants with a modest amount of low-impact meat than by eliminating meat entirely and replacing a large share of the meat's protein and calories with dairy," the report said.

It added: "The country-specific results presented here could provide nutritionally viable pathways for high-meat-consuming countries, as well as transitioning countries that might otherwise adopt the Western dietary pattern."

Overhauling a Food System

In the economics-focused report released Monday, the Land and Food Use Coalition, a group of scientists, economists and environmental groups that formed in 2017 to help overhaul food and land use systems with the goal of achieving global climate targets, lays out 10 strategies for transforming food and land use systems, including a more diverse diet that's lower in livestock-based foods, particularly in high-income countries.

It recommends that global consumption of meat from cattle and sheep "should be halted and gradually reduced," but "in some cases this means people will need to eat more meat, and in others less." For example, the report says, children and women of childbearing years in sub-Saharan Africa who are among the world's undernourished populations, will need more protein to meet their nutritional needs, while people in high-income countries will need to cut back for both health and climate reasons.

The coalition found that if governments and societies invested about $350 billion a year—about 0.5 percent of GDP—in carbon-friendly agriculture and other sustainable food and farming measures, the world could save $10.5 trillion annually in environmental and health costs by 2050.

"The productive potential of the earth is plenty big enough to return 1.2 billion hectares of land to nature and produce healthy food for a growing population," said Per Pharo, the report's lead author and director of Norway's Climate and Forest Initiative. "There are no technical, financial or biophysical barriers to doing this."

Farmers Have Important Roles to Play

There are, however, political and systemic barriers.

"The goal of this report is to say this can be done, it should be done," Pharo said. "We haven't been able to mobilize the political will."

The report points out that governments spend about $700 billion supporting agriculture globally, but only about 1 percent of that is directed toward beneficial environmental practices. Governments need to substantially increase their support for farmers in ways that incentivize regenerative and carbon-friendly farming, the authors write.

"We are extremely aware that [farmers] will be part of solving this," Pharo said. "We have asked them to deliver and they've delivered. ... This is not about blaming farmers. It's a question of aligning more people behind the mission of transformative change."

Published Sept. 18, 2019