Land-use change from livestock occurs mainly through the conversion of forests and grasslands into pasture for grazing animals and cropland to grow livestock forage and feed; many “pasture-raised” and “grass-fed” animals are still fed supplemental forage.
Beef cattle use nearly 60% of the world’s agricultural land but account for less than 2% of global calories and 5% of global protein consumed. Compared to common plant proteins such as beans, peas and lentils, beef requires more than 20 times more land and emits 20 times more greenhouse gas emissions per gram of edible protein.
While some sustainable food advocates propose shifting to “grass-fed” beef and dairy, there is only enough pasture land in the United States to support 27% of current beef production.
A recent Harvard study found that shifting to exclusively pastured systems would require 30% more cattle and increase beef’s methane emissions by 43% just to keep up with current demand. A 2012 study found that a shift to all grass-fed beef in the United States would require an additional 200,000 square miles of land — an area larger than the states of New York, Pennsylvania, Florida and Ohio combined. Industrial meat production in factory farms and feedlots is unquestionably unsustainable, exploitative and inhumane, but there’s simply not enough land to shift current levels of production to a grass-fed system.
Indeed, unless there is a major shift in dietary trends, scientists estimate that by 2050 global agricultural land will need to expand by 31%, with most of that extra land used for pasture for meat and dairy. Experts have warned that in order to feed the global population and meet the minimum climate targets, we will need to produce 50% more food by 2050 on the same amount of land or less, and reduce GHG emissions from agriculture by two-thirds.
This will not be possible without major reductions in meat and dairy production. A global shift to plant-based diets could free up 75% of agricultural land and still plentifully feed the world, according to Oxford researchers.
The conversion of forests, grasslands, and other ecosystems to livestock pasture and feed cropland is a leading driver of deforestation, biodiversity loss, GHG emissions, increased wildfire incidence, and zoonotic disease transmission.
These impacts are frequently embedded in a negative feedback loop whereby the intensification of one exacerbates and increases one or more of the others. More deforestation, for example, means more global warming, which leads to hotter temperatures, more frequent and longer droughts, and more vegetation drying out, which increases the risk of wildfires, which leads to more deforestation.
According to the Food and Agriculture Organization of the United Nations, deforestation is the second leading cause of climate change after the burning of fossil fuels and accounts for almost 20% of all GHG emissions.
Forests function as carbon sinks — trees absorb about one-third of carbon emissions produced worldwide — but when forests are destroyed, that carbon is released into the atmosphere as CO2, a GHG. Trees also remove CO2 from the air through photosynthesis, but deforestation vastly reduces the amount of trees providing this service, further increasing the carbon dioxide in the air.
More than 18 million acres of the Earth’s forests are currently lost every year — the equivalent of 27 soccer fields of forest lost per minute. About 10,000 years ago, 50% of Earth’s land surface was covered in forests. But a full half of those forests have been lost due to human pressures, with much of the destruction occurring from agricultural intensification in the last century alone. Indeed, clearing land for cattle pasture is now estimated to be the number one driver of deforestation worldwide.
Cattle pasture currently occupies 111 million acres of land deforested between 2001 and 2015, accounting for 36% of all tree cover loss associated with agriculture in that span of time. During that same period, the conversion of forests to pasture resulted in five times more deforestation globally than for any other leading deforestation-driving commodities, with the bulk of forest replacement by cattle occurring in tropical forests.
Most familiar perhaps are the hundreds of thousands of fires that have seen the Amazon rainforest in a near perpetual state of burn for the past several years. The overwhelming majority of these fires have been deliberately set to clear land for cattle pasture, in what is commonly known as “slash-and-burn” agriculture. Cattle grazing alone is responsible for a shocking 80% of current deforestation rates in the Amazon.
But it’s not just rainforests being decimated. Some 42% of global pastureland used to be forests or woody savannas.
And while people are increasingly aware of the association between grazing and destruction of the Amazon, far fewer are aware of the destructive ways livestock grazing has dramatically altered Earth’s landscape globally.
In the western United States, cattle ranching has quietly been devastating old-growth forests for decades. More than one-third of U.S. land is used for pasture, making grazing the single largest user of land in the contiguous 48 states.
Much of this grazing happens on federal public lands overseen by the Bureau of Land Management, which leases it out to livestock owners in the West. Livestock currently utilize more than 70% of lands managed by the BLM and the U.S. Forest Service — nearly 400,000 square miles annually.
In order to create more pasture for cattle in the United States, millions of acres of native pinyon-juniper forest and iconic sagebrush steppe have been systematically eradicated for decades and reseeded with non-native grasses for cattle. These massive deforestation projects are falsely framed as “Fire Suppression” and “Rangeland Restoration” programs, funded by taxpayers who are kept in the dark via obfuscating stewardship jargon.
From the woodlands of the American West to the Amazon rainforest, from the grasslands of Argentina to the pastures of Madagascar, with Eastern Australia designated a full-blown “beef deforestation hotspot,” and much of Iceland, even, irreversibly transformed to desert owing to tree-clearing for sheep pasture, the conversion of land for grazing is ravaging ecosystems on a global scale.
Restoration of native ecosystems, including forests, could remove significant amounts of carbon dioxide from the atmosphere. But the land use requirements of our current food system limit ecosystem restoration potential, thereby imposing a “carbon opportunity cost,” that is, the potential for natural CO2 removal.
Animal food production particularly, with its disproportionate land use, incurs a major sequestration opportunity deficit. Harvard researchers calculated the total carbon opportunity cost of animal agriculture to be 152.5 (94.2–207.1) gigatons of carbon, with pastures for ruminant meat and dairy production representing the majority — 72% — of the total carbon opportunity cost. A U.N.-backed report published in 2021 concluded that if all pasture around the world that was once forest was returned to its native state, it would store 72 billion tons of carbon — roughly equivalent to seven years of global emissions from fossil fuels.
Climate scientists have urged that conserving forests and planting more trees could provide nearly one-third of the climate mitigation needed in the next 10 years.
Mass reforestation especially has been promoted as one of the most promising carbon sequestration solutions, with the potential to store as much as two-thirds of all the carbon released into the atmosphere since the Industrial Revolution. But tree-planting at this scale will only be possible through major reductions in food-related land use.
Researchers estimate a global shift to plant-based diets could release enough agricultural land by 2050 to sequester 332–547 GtCO2, with a projected 66% chance of limiting warming to 1.5°C. In the United States, a switch from beef to beans would free up an estimated 42% of U.S. cropland that could be used for rewilding.
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