What’s the most common element in Earth’s atmosphere? Did you guess oxygen? You’d be absolutely wrong. The correct answer is nitrogen. Everyone breathes it all their lives. But when nitrogen combines with other chemicals, especially when those compounds make fertilizer, they threaten the sustainability of humans and a lot of other organisms.
The May 2013 edition of National Geographic magazine includes the article, “Our Fertilized World.” It explains how the deployment of nitrogen-based fertilizers from factories worldwide is threatening our water supplies. That creates the irony of food creation threatening the lifeblood of virtually all living things.
More than a hundred million tons of nitrogen fertilizer is employed in agriculture each year in order to feed our rapidly expanding population. “Our planet’s soil simply could not grow enough food to provide all seven billion of us our accustomed diet,” says the article’s writer, Dan Charles. “In fact, almost half of the nitrogen found in our bodies’ muscle and organ tissue started out in a fertilizer factory.”
In our book Enough of Us, we describe how runoff of these fertilizers contaminate groundwater, enter rivers and streams and find their way to lakes; even the Great Lakes. Eutrophication is the term used for the process by which a body of water becomes enriched in dissolved nutrients that stimulate the growth of aquatic plant life usually resulting in the depletion of dissolved oxygen in the water. This can be fatal for other plants and fish. Charles asks the succinct question, “How much clean water and air will survive our demand for fertile fields?”
As China had increased its productivity in all economic arenas, and as it must feed its growing populous, it has embraced the use of nitrogen fertilizers. And it has gone whole hog in doing so, because of the fear of that the famines of days of old might return. Some estimates put China’s over usage at 60 percent. The consequences have been calamitous as it has overused fertilizers that contaminate water supplies and air.
As far as locations go, however, the overuse of nitrogen compounds is becoming a worldwide problem. And it’s not just the need for food that’s to blame. Combustion engines, like those in generators and vehicles release nitrogen oxides into the atmosphere. When those compounds fall with the rain, they become unintended fertilizers as well.
While agricultural scientists work on alternative fertilizers, “populations continue to expand, and meat is growing more popular. Feeding pigs or cattle demands several times more agricultural production than does using that grain to directly nourish people.”
In the United States, the effects of all this over-fertilizing have been dramatic . . . and unfortunate. The photo from the May National Geographic (http://ngm.nationalgeographic.com/2013/05/fertilized-world/essick-photography) shows Lake Erie in 2011 when a third of it was covered with an algae bloom that made it look as much like a field of clover as a freshwater lake. The enormous dead zone in the Gulf of Mexico is fed by a nutrient-rich flow from the Mississippi.
Africa, whose population is growing rapidly, has the opposite problem, which is a good thing environmentally speaking, but a nightmare for much of its population. “Many in Africa’s rural villages have fallen into a set of vicious circles. Fearing hunger, they concentrate on crops like rice or corn that deliver maximum calories but that tend to strip nutrients from the soil. Depleted land delivers increasingly poor harvests, leaving farmers too financially strapped to afford fertilizer … And since there is little demand for commercial fertilizer, no one makes it locally, so it’s imported and expensive.”
The question for Africa is whether farmers there will learn techniques for balancing nutrients by planting a wider variety of crops, or move into the sphere of those who add fertilizers to the soil at the jeopardy of water resources.
Whatever the agricultural future brings, however, will be greatly influenced by the increasing demand for crops resulting from a population expected to grow by more than 40 percent by the end of the century. Along with that growing population will come increased demand for livestock that consumes crops inefficiently, and crops grown for ethanol to power motor vehicles.
As long as human populations grow and poor strata of society move into the resource-gobbling middle class, we can just add fertilizer pollution to the list of demons threatening human sustainability and planetary health.