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millennium essay
Detonator of the population explosion
WIthout ammonia, there would be no inorganic fertilizers, and nearly half the world would go hungry. Of all the centurys technological marvels, the HaberBosch process has made the most difference to our survival.
Vaclav Smil
What is the most important invention of the twentieth century? Aeroplanes, nuclear energy, space
flight, television and computers will be the most common answers. Yet none of these can match the synthesis of ammonia from its elements. The world might be better off without Microsoft and CNN, and neither nuclear reactors nor space shuttles are critical to human well-being. But the worlds population could not have grown from 1.6 billion in 1900 to todays six billion without the HaberBosch process.
Every one of us has to eat ten essential amino acids to synthesize the body proteins needed for tissue growth and maintenance. Agricultural crops and animals fed on crops supply almost nine-tenths of these amino acids in food proteins (aquatic species and animals grazing on grassland provide the rest). The yield of intensive agriculture is almost always limited by the availability of the nitrogen needed to produce these proteins.
Nitrogen comes from biofixation (by Rhizobium bacteria symbiotic with legumes and by cyanobacteria), from atmospheric deposition, and from the recycling of crop residues and animal manures. But these...