As much as it might seem one of the more obscure of the basic elements, with little uses that everyday people would be able to name, phosphorous is essential to our existence, as a building block of DNA and, essential to modern civilization, a key ingredient in industrial fertilizers. It is also running out.
Phosphorous is the 6th most common element on Earth, and 90% of its use by humans is in food production. There is no phosphorous cycle, no natural means for restoring and recycling it once it’s used. In our world, once it’s gone, it’s gone. And it’s currently going. Fast.
Since the 1960s, phosphorus use has gone up by five times and is set to double in the next thirty years, as the global population continues to boom, while known stocks of phosphorous continue to dwindle with, by some estimates, just 80 years worth left.
In response, a group of international experts has come together to issue a warning about the perils we face, published in the journal Environmental Science & Technology. They are urging government and industry worldwide to train a new generation of professionals with a focus on preserving and sustaining stocks of vital nutrients.
Ecologist Kaspar Reitzel, one of the experts behind the report, insisted that such people should be more than phosphorus specialists, instead of being “system thinkers” who involved inappropriate decision-making around the uses of phosphorus. Such a group, the experts suggest, could secure international phosphorus management and a clean environment for our future.
One of the key issues is how poor we have been at caring for our limited stock of phosphorous. Mining techniques have changed very little over the decades, and the fertilizers which account for much of our phosphorous use are generally only used once before they are swept off the land by the water cycle and into the sea (incidentally causing pollution problems in the process).
The US began the race to deplete phosphorus supplies in order to fertilize farmland in the 1970s and 80s. The USSR was quick to follow, the race is dominated by the two Cold War superpowers for decades, but now the rest of the world is catching up. Already China and India account for 45% of the world’s phosphorous use.
The estimates of 80 years of remaining phosphorous stocks are based on current use remaining stable. In reality, we can see developing countries using ever more phosphorous-heavy fertilizers, meaning those stocks will be diminished even faster.
The corollary of this in the near term would be increasing food prices, hunger, internal and geopolitical instability, and, in the long term when those stocks are gone, mass starvation.
The 40 experts writing in Environmental Science & Technology have suggested that one response to this would be to create a so-called closed-loop recycling system. This would be a system whereby phosphate could be reused approximately 46 times in different guises; as fuel, as fertilizer, and as food.
This was how farming used to be, with plants grown on farms fed to working and food animals whose manure, in turn, replenished the phosphorous in the soil.
Some suggest traditional agricultural methods, particularly crop rotation, could help keep phosphorous on agricultural land more efficiently, without needing to draw more from artificial sources. Fungus, such as arbuscular mycorrhizal fungi, can also be useful in affixing and recovering usable phosphorous.
One other recycling option is the use of struvite. This is a hard, white substance, technically known as magnesium ammonium phosphate, that is a by-product of human waste, often found blocking sewage systems.
In pipes, it can create blockages in human kidney stones, but in farming, it actually outperforms conventional fertilizers, although its costliness means it has so far rarely been used.
But the experts argue that this, as well as the other options presented, need to be acted on, no matter the current cost. With phosphorous stocks already dwindling, and usage rapidly increasing, as billions more mouths to feed are due to be born in the coming decades, something will need to be done as the costs of running out of phosphorous, with no way of returning it to human use, are far greater than the expense of extracting it from difficult sources.
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