Over the Last 40 Years, We've Squandered More Than a Third of the World's Farmland
A lot of particulars need to be considered when choosing a piece of land to farm. Preferably, a plot will be relatively flat, have good drainage, and will be layered with plenty of rich organic matter that will nurture the crops to be grown there. In many parts of the world, such land is hard to come by—and ensuring that a good piece of farmland remains a good piece of farmland for years to come is no easy task.
The food we eat (and the food that feeds the meat we eat) is grown on some 5.4 million square miles of such arable land globally, which together is roughly the size of the Lower 48 and Mexico combined. While that may seem like an enormous global farm, that land is disappearing—and quickly. According to research presented Wednesday at the Paris climate talks, more than a third of the world’s arable land has been lost to erosion and pollution over the last 40 years.
The researchers, who arrived at their conclusion after analyzing a decade's worth of studies, called it a “catastrophic” loss.
“It takes about 500 years to form 2.5 cm of topsoil under normal agricultural conditions,” Duncan Cameron, professor of plant and soil biology at the University of Sheffield, said in a statement. A standard plowed field loses topsoil at 10 to 100 times that rate.
With yields expected to decline as climate change causes temperatures to rise and turns dramatic, erratic weather patterns into a new normal—both flooding and drought can result in topsoil loss—the global food supply depends not only on vastly reducing the loss of topsoil but turning to agricultural practices that help to build it back up.
Many of the potential solutions suggested by Cameron and his fellow researchers from University of Sheffield’s Grantham Centre for Sustainable Future will be familiar to some: no-till farming, intensive crop rotations, compost use, cover crops, and other practices championed by sustainable agriculture advocates. But when it comes to industrial-scale agriculture in the United States, except for no-till farming—which has been widely adopted across the corn belt in the last decade or so—these practices are far from being the status quo. In the U.S., only 3 to 7 percent of farms use cover crops, for example, according to the USDA Economic Research Service.
The researchers also point to biotechnology as a potential solution. Instead of glyphosate-tolerant commodity crops, they envision new plant varieties that would be altered to thrive on soil nutrients made available through symbiotic relationships with soil microbes rather than chemical fertilizers. They also propose unlocking new sources of non-chemical fertilizers, such as human waste.
The recommendations would represent nothing short of a full-scale upheaval of contemporary global agriculture—but with more topsoil washing off fields every day, the stakes are undeniably high.