How can eating less meat help fight climate change?

LONDON - Cutting back on meat can be good for human health and for animal welfare, but it is also one of the best ways to fight climate change and nature loss, scientists say.

Meat eating is rising globally as incomes rise in poorer and middle-income nations, though consumption is falling in some places due to the growing popularity of vegetarian or vegan diets and a boom in the supply of tastier meat substitutes.

So why is cutting down on meat so important for the environment? Here are a few key reasons - and some ideas on how a bigger shift towards plant-based diets could be achieved:

Livestock uses up 70% of agricultural land

Crops used to feed livestock - including corn and soybeans - eat up 40% of the world's total cropland, according to a study published in the Annual Review of Resource Economics journal in April. 

Another 2 billion hectares (4.9 billion acres) of grasslands around the world - about four times as much land as is used to grow crops - are dedicated to livestock grazing, it found.

That means about 70% of the world's agricultural land is used for producing meat and dairy goods - even though those products amount to less than 20% of the total food calories available globally.

Animal farming also soaks up a quarter of the freshwater used each year, and is responsible for as much as two-thirds of climate change-fuelling emissions from food production, the report found.

Animals such as cattle, sheep, goats and buffalo that ferment the food they eat in the process of digesting it are also major producers of methane gas, a powerful climate change driver.

Pressure on forests, biodiversity

With the world's growing population on track to reach 8 billion people next month, the need for more land to feed livestock is putting pressure on forests and other uncultivated, natural areas that are rich in biodiversity.

In Brazil, the expansion of pastures for grass-fed cattle and soy plantations - used largely to feed chickens, pigs and other farm animals - are the major driver of soaring Amazon forest losses. 

"Land expansion for pastures and cropland is a major contributor to climate change but is also the predominant driver of natural habitat destruction, with serious negative effects on wild biodiversity," the Resource Economics study noted.

About 13 billion hectares (32 billion acres) of forest is lost globally each year to expansion of grazing and cropland, to feed both animals and people, according to the U.N. Food and Agriculture Organization. 

Less meat means more wheat

Russia's invasion of Ukraine this year has slashed exports of wheat from what was once a major wheat-producing region, leading to rising global food prices and shortages or high costs in major importers from Africa to the Middle East.

But with about half of European grain production going to feed animals, a small cutback in meat eating just in Europe -equivalent to 8% of grain produced on the continent - could effectively make up the global difference in wheat availability, environmental group Greenpeace said in a March analysis. 

To respond to war-related wheat shortages and rising prices, many governments around the world have tried to ramp up production.

But lowering demand for grains - by reducing the number of grain-fed animals - is a simpler way to solve the problem, said Laura Wellesley, a food security and sustainable diets expert at London-based think-tank Chatham House.

"The elephant in the room with policy responses is no discussion of the vast quantities of grain and fertiliser going into the livestock system," she told a conference in Exeter last month.

"There's enough supply of staple crops if they're not diverted to livestock (and) biofuels," she said.

What might reduce meat consumption?

Increasingly tasty and more widely available meat alternatives are helping many people make the switch towards a plant-based diet, despite questions about the new products' carbon footprints, health benefits and affordability.

Government policy that requires meat alternatives in schools or other public procurement, that makes eating less meat part of national dietary guidelines or bans the advertising of meat products can also help ramp up a shift to plant-based diets, said Scarlett Benson, of the global Food and Land Use Coalition.

China's new five-year national plan includes heavy investments in lab-grown meat, for instance, Benson said - a move that could help curb the country's fast-growing demand for meat and its huge appetite for imported animal feed.

China is currently the largest importer of Brazil's fast-expanding soybean production.

Affordable, delicious meat alternatives "could take the carpet out from under livestock farming", said Tim Lenton, director of the Global Systems Institute at Britain's University of Exeter.