To his dismay, he found that the world had actually passed peak phosphate back in 1989! Until now, humanity has been comforted by vague predictions that there is a fifty to one hundred years’ supply of P, and we have been negligently content to bequeath the worrying to our grandchildren. But the point about peak theory is that the trouble begins well before the supply is exhausted— in fact, it starts at the point when demand begins to outpace supply, which is where prices start to jag about, reflecting people’s apprehension over approaching scarcity.
Scarier still is the fact that, although there may be energy substitutes for oil or gas if supplies run low or become too expensive, there are no substitutes for phosphorus. It is fundamental to the chemistry that supports all forms of life. It is essential to crop and pasture No phosphate, no food. When plants do not have enough P to grow, scientists refer to them as “phosphorus- limited.” You can throw all the other nutrients you like at them and they will not grow. Unless humanity can find twice as much P to sustain a doubling in food output or, better, recycle the sources we already have, the blunt truth is that human civilization as we know it is phosphorus- limited. Any biologist can tell you that this means “headed for trouble.”
The FAO suggests that there is no need to panic just yet— there remains a market surplus of nutrients, including P. But such observations breed complacency: already demand is outrunning the discovery of new resources. And as food demand rises inexorably as we approach midcentury and as farming systems modernize and intensify, the quality of rock phosphate reserves will decline as the best ones are mined out, driving up prices to the farmer and escalating international tensions over what’s left. People talk about the wars over oil, diamonds, or water; that nations could go to war over phosphate or potash so they can feed their children has not yet surfaced on the global agenda. It will.
For nitrogen the case is somewhat different. There is an abundance of N in the air that can be extracted to make fertilizer. Also, peas, beans, lentils, and other legume crops can add nitrogen to the soil for other crops to benefit from. The industrial production of nitrogen fertilizers as well as their use involves the liberation of large volumes of green house gases, however. Conventional means of producing N industrially may thus eventually have to be phased out in favor of more sustainable systems, including, for example, the ge ne tic modification of crops so they can fix their own nitrogen from the air, the development of improved strains of legumes and better crop rotations, and the design of suites of soil bacteria that enhance soil nitrogen. All this will require a global research effort into alternative ways to increase nitrogen fertility in agriculture no less massive and urgent than what is now being devoted to clean energy.
Leaky Farms
