Fertilizers: challenges and solutions

At the start of the 20th century, German chemists Fritz Haber and Carl Bosch developed a method for taking nitrogen from the air and melding it with hydrogen. It would prove to be one of the great scientific advances of the century.

Combined, the two elements made liquid ammonia, a key ingredient in synthetic fertilizers, which would drive an unprecedented agricultural expansion and help feed a fast-growing world.

But there has been a downside. During the last 100 years, the amount of man-made nitrogen compounds in water, soil and the air has doubled – an increase driven in large part by the widespread use of synthetic fertilizers.

Nitrogen is essential for life on Earth but in excess, it is a dangerous pollutant and is poisoning water bodies, plants, animals and humans, while driving climate change through emissions of the potent greenhouse gas, nitrous oxide. Though little known to the general public, experts call the flood of excess nitrogen one of the most severe pollution threats facing humanity today.

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