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Oliver Morton

The Music of Science

Nitrogen fertiliser magically transformed agriculture. Today we need a new spell to clear up the results

Oliver Morton | November/December 2015

The most important thing about Mark Sutton is his contribution to the world’s efforts to clean up nitro­gen pollution, but that is not the most striking thing about him. With the earnest air of an English schoolboy of yesteryear, an ability to get into great detail about his enthusiasms very quickly and, on occasion, socks with his sandals, he is, give or take a scar and a few decades, the spitting image of Harry Potter.

Young Potter’s saga is about facing up to consequences: his life is entirely shaped by the unfinished business of great struggles fought at and before the time of his birth. So is Sutton’s saga. A professor at the Centre for Ecology and Hydrology just outside Edinburgh, he is devoting his career to reining in the adverse effects of one of the most profound transformations of the 20th century.

In the late 1800s leading chemists such as William Crookes, Henry-Louis le Châtelier, Wilhelm Ostwald and Fritz Haber realised that if Europeans were to continue to enjoy the benefits of higher output of both wheat and ammunition (the manufacture of which needs reactive nitrogen), new sources of nitrogen would have to be found. Nitrogen is not exactly hard to come by — it makes up 80% of the atmosphere — but that atmospheric form of the element is inert and living things can use it only when it is in reactive form. Lightning can make the necessary changes; but before humans took a hand in it the hard graft of providing nitrogen in a form that could be used to make vital protein and DNA was mostly undertaken by microbes.

But the needs of a growing technological civilisation outstripped what the bacteria could offer; it was time, as Crookes put it, for “men of science” to take a hand; if they did not the world faced “a catastrophe little short of starvation…and even the extinction of gun powder!” The problem of making reactive nitrogen from the air was solved a decade later by Fritz Haber, and both munitions and agriculture were changed for ever. After the second world war nitrogen fertilisers were fundamental to huge increases in rich-world farm productivity; at the core of the “green revolution”, they transformed agriculture in many poor countries. That a population twice as large as that of 1970 is now better fed with no more agricultural land used in the process is down to this great fertilisation.

The world’s factories now produce 144m tonnes of reactive nitrogen annually, far outstripping all the microbes of the Earth’s soils. This deliberate commandeering of the nitrogen cycle is arguably the most profound of the many impacts humanity has so far had on its home planet. To capture the ambition of the undertaking Sutton and his colleagues sometimes refer to it as a form of geoengineering – a deliberate technological intervention on the scale of the great cycles of nature. (It is an analogy I develop in my new book, “The Planet Remade”.)

The world-changing benefits of this geoengineering have come with enormous costs. In the wrong places – which range from the inside of people’s lungs to the ozone layer, by way of dead zones in coastal seas, polluted drinking water and damaged soils – reac­tive nitrogen can do a great deal of harm. According to “The European Nitrogen Assessment”, a hefty tome Sutton and his colleagues produced four years ago, pollution by nitrogen-based compounds then cost the European Union between €70 billion and €320 billion a year; the whole world’s bill might handily top a trillion. Were it not for climate change, this would probably be the environmental problem the world discussed the most.

Clive Hamilton, an Australian philosopher, sometimes invokes the “sorcerer’s apprentice” sequence from Walt Disney’s “Fantasia” to illustrate the dangers of using geoengineering to avert climate change. Told to clean up his master’s chamber of secrets, Mickey enchants a mop and pair of pails. As they set to work the mouse nods off, only to be woken from a reverie of omnipotence by the Stakhanovite mop’s flooding of the workshop. Things are completely out of control when the magus returns, goes Charlton Heston on the waters, and disciplines his errant disciple. The lesson for geoengineering is that there are powers with which the Mickeys of the world should not meddle.

If you accept the nitrogen revolution as a form of geoengineering, though, this story gets stood on its head. It is the great magicians who cast the spell (Crookes’s rather fine beard and whiskers, along with his keen interest in spiritualism, would have made him at home in the Hogwarts staffroom), and the consequences of their magic are even greater than they intended. But these effects, though galling and costly, are not irreversible.

It is possible to clean things up – and this is what the sorcerers’ latterday apprentices are trying to do. Rather than dreaming on the job, they are taking a realistic look at the problem and putting together a grimoire of practical solutions. Instead of Fantasia’s thoughtless catastrophe, we see a mindful, incremental amelior­ation of unanticipated harm. Given that human sorcery is sure to change the planet further, and that no such intervention, any more than any other great magic, can be free of consequences, the example of diligence provided by apprentices like Sutton offers a modicum of comfort.

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