The biggest problem you've never heard of

Tuesday, August 17, 2010
by Margaret Coulombe, illustration by Adrian Smith

Phosphorus is a key component of fertilizers used to grow foodThe mineral phosphorus (P) is critical for growing bones, teeth and DNA. “P” is also a key component of the fertilizers used to produce our food, as important to agriculture as water. But is P, like oil, peaking? Could we run out of this essential resource? Scientists in Europe, Australia, the United States and elsewhere see growing evidence that the answer is yes. But when? That is the question.

 Scientists predict that we will start seeing a decrease in P production starting as early as 2034 to as late as 2070 or beyond. According to Arizona State University ecologist James Elser, most people don’t realize that phosphorus comes from mines and that these mines are limited.

“Our current use of phosphorus is not sustainable,” Elser says.

Putting real numbers on predictions for “the biggest problem you’ve never heard of” has spurred the creation of the “Sustainable P Initiative” at ASU, the first focused effort in the United States to examine growing concerns about “phosphorus, food and our future.”

The initiative is a partnership with the Arizona Science Center. It is aimed at motivating change and advancing the design of new technologies, conservation strategies, recycling measures, and agricultural and wastewater practices to close the human-P cycle.

“Globally, farmers use more than 17 million tons of mined P on their fields to produce their crops, at a cost that represents nearly 30 percent of their budget,” says Mark Edwards, an ASU agribusiness expert.

Nearly 90 percent of P reserves are located in only five countries: Morocco and Western Sahara, China, South Africa, Jordan, and the United States. With only 12 mines in the U.S., which will be depleted within 20-30 years, people should be concerned. “Sustainability needs to become a priority. Many regions of world are completely dependent on imports for fertilizer. We need new ways to recycle, reclaim, and reuse what we have,” says Daniel Childres, a sustainability researcher at ASU.

Rising energy costs complicate predictions on when mines might run out. So does limited knowledge about the reserves themselves. Donald Burt, an ASU professor of geology, believes that peak phosphorus production might actually happen considerably earlier than 2034, depending on oil supplies. “Energy use impacts not just mining, but also packing, storing, transporting and applying phosphate rock and fertilizers,” says Burt.

Another concern is inefficient use and overuse of fertilizers. There are also problems with runoff from urban and agricultural sites, which dumps P into waterways, creating ecological and economic damage, such as massive coastal “dead zones.”

The ASU scientists hope to work closely with partners in agriculture, industry, government and the community to find solutions to the P problem.

“The solutions are out there. We just need to start thinking now,” Elser says. “Conservation of P is one effective strategy. In the pathway from mine, to farmer, to fork, and beyond, there is significant P waste.” For example, ‘waste’ P in urine, feces, and agricultural runoff could be transformed into a valuable source of fertilizer. A vegetarian diet would also reduce waste.

Learn more about the Sustainable P Initiative: http://sustainablep.asu.edu/