A meat-inclusive diet often comes with a side of environmental caveats, including livestock’s contribution to global warming, its contribution to deforestation, and the stress it places on a bevy of increasingly precious resources, from water to land. Now, a group of researchers want to add another concern to the meat-eater’s plate: worldwide species extinction.
According to a recent study published in Science of the Total Environmentby researchers at Florida International University in Miami, livestock production’s impact on land use is “likely the leading cause of modern species extinctions” — a problem the researchers think will only get worse as population growth increases the global demand for meat.
The study is particularly interesting to scientists because research linking livestock’s relationship to biodiversity loss has been lacking, Gidon Eshel, a geophysicist at Bard College who was not involved in the study, told Science.
“Now we can say, only slightly fancifully: You eat a steak, you kill a lemur in Madagascar. You eat a chicken, you kill an Amazonian parrot,” Eshel said.
To understand livestock production’s impact on biodiversity, researchers at Florida International University mapped areas that have exceptionally high percentages of native plants and animal species — known as biodiversity hotspots.
The researchers then mapped areas where livestock production is expected to increase in the future, and determined how much land would be lost as a result of expanding meat operations, using data from the Food and Agriculture Organization and other studies about historic livestock production and land use conversion in those areas. Then, they compared the biodiversity hotspots with the expected expansion of meat production.
They found that of the areas expected to have the greatest conversion of land use for agriculture — from forest to land dedicated to livestock production — 15 were in “megadiverse” countries that have the greatest diversity of species. The study concludes that in the 15 “megadiverse countries,” land used for livestock production will likely increase by 30 to 50 percent — some 3,000,000 square kilometers (about 741 million acres).
“These changes will have major, negative impacts on biodiversity,” Brian Machovina, the study’s lead author, told Science. “Many, many species will be lost.”
Several studies have suggested that the Earth is currently in the midst of thesixth mass extinction, caused largely by human activities. Animals are hunted and sold for trade, climate change is disrupting migration and mating patterns, extreme weather is threatening animal populations, and deforestation is fragmenting crucial habitat. But all of those causes, Machovina and his colleagues claim, pale in comparison to the threat of habitat loss driven by demand for meat, which the study claims “will cause more extinctions than any other factor.”
And though meat consumption in the United States has fallen steadily since peaking in the 1970s, meat consumption worldwide continues to rise, driven by technological advancements, liberalized trade, and growing economies. Livestock production is also an incredibly important source of economic security for millions of the world’s poor, providing stable income for 987 million around the world.
Machovina and his colleagues do suggest some mitigation efforts that could curb the loss of biodiversity from meat production — namely, eat less meat. The study says that in order to limit the worst biodiversity losses, the average diet should get no more than 10 percent of its calories from meat, and that pork, chicken, and fish are less resource-intensive options for meat eaters.
But while meat production can have a negative impact on species biodiversity and climate change, it’d be unwise to quit meat production altogether, Clayton Marlow, a grassland ecologist at Montana State University, Bozeman, told Science. He argues that the real issue facing biodiversity loss isn’t the expansion of meat production, but the expansion of urban sprawl, which takes away land that could potentially be used for agricultural production.