Nitrogen – the good and the bad
- Nitrogen is the most abundant element in our atmosphere.
- Although 78 per cent of the atmosphere is nitrogen, this nitrogen exists almost entirely in a form that is unusable by most organisms.
- Atmospheric nitrogen can be made usable or ‘reactive’ through natural processes (e.g. nitrogen fixation by legumes such as soybeans) or artificially.
- The discovery a century ago of an industrial process that converted nitrogen in the air to ammonia that made the manufacture of nitrogen fertilizers possible was followed by a spectacular increase in global food production.
- In the past 150 years, human-driven flows of reactive nitrogen have increased tenfold, contributing to a dangerous accumulation of unused reactive nitrogen.
- The uptake by crops of nitrogen as fertilizer is limited. Each year, 200 million tonnes of reactive nitrogen – 80 per cent – is lost to the environment, leaching into soil, rivers and lakes and emitted to the air. As a result, ecosystems are over-enriched, biodiversity lost and human health affected. In some forms, it contributes to ozone depletion and climate change.
- The annual cost of lost nitrogen resources is estimated to be around US$200 billion..
