The World’s Farms Are Hooked on Phosphorus. It’s a Problem
Disrupting Earth’s chemical cycles brings trouble. But planet-warming carbon dioxide isn’t the only element whose cycle we’ve turned wonky—we’ve got a phosphorus problem too. And it’s a big one, because we depend on this element to grow the world’s crops. “I don't know if it would be possible to have a full world without any mineral phosphorus fertilizer,” says Joséphine Demay, a PhD student at INRAE, France’s National Research Institute for Agriculture, Food and the Environment.
Since the 1800s, agriculturalists have known that elemental phosphorus is a crucial fertilizer. Nations quickly began mining caches of “phosphate rock,” minerals rich in the element. By the middle of the 20th century, companies had industrialized chemical processes to turn it into a form suitable for supercharging crops, hardening them against disease and making them able to support more people and livestock. That approach worked remarkably well: The post-World War II “Green Revolution” fed countless people thanks to fertilizers and pesticides. But sometimes there’s too much of a good thing.
We have liberated Earth’s caches of phosphorus so rapidly that the element now pollutes freshwater ecosystems, where excesses cause harmful algal blooms, infiltrates the snowpack, and decreases levels of dissolved oxygen in lakes and rivers. Studies suggest that humanity has grown too dependent on it for feeding the planet—and we are running out of this nonrenewable resource, which comes from geologic deposits that take millenia to form. When it washes from soil into waterways, it essentially disappears forever. A looming “peak phosphorus” moment threatens to increase prices and foment political tension if demand eclipses supply, as a large majority of reserves exist only in one corner of North Africa.
