Exploring nitrogen in Future Earth

Spreading nitrogen fertilizers using a leaf colour chart to determine dosage in Karnal, India. Photo: Prashanth Vishwanathan/CCAFS

The sustainability of the world’s population depends fundamentally on nutrients, including reactive nitrogen (Nr) and phosphorus (P). Industrially produced Nr-containing fertilizers are essential to global food security and have been the main driver of dramatically improved agricultural yields over the last 60 years. At the same time, nutrient loads to the atmosphere, terrestrial and aquatic systems have increased drastically, leading to a cascade of environmental, human health and climate impacts, including impacts on water quality, air quality, climate change, ecosystems and biodiversity, and stratospheric ozone.

The issue of altered biogeochemical flows in the phosphorus and nitrogen cycles is identified as one of the four ‘planetary boundaries’ that have been exceeded as a consequence of human activities. (Rockström et al., 2009/2015). Reactive nitrogen is also linked to the carbon cycle and impacts on climate change. Improved management of the nitrogen cycle is essential for meeting global sustainability challenges.

This initiative acknowledges both the benefits and the problems of nitrogen use, and the close linkages between nitrogen in its application in agricultural fertilizers, manures and human wastes, as well as the coupled complexity arising from combustion sources of emissions of nitrogen oxides (NOx) to the atmosphere.

Key interactions of reactive nitrogen include:
  • Food insecurity – inadequate Nr (and other fertilizer components) leading to insufficient food production in developing regions of the world, and especially sub-Saharan Africa.

  • Energy security – fossil fuel burning produces Nr in the atmosphere and limiting these emissions uses additional energy. Alternatives, such as biofuels, will affect food security and will require fertilization, and lead to loss of Nr to the environment.
  • Soil quality – over-fertilization and excess atmospheric Nr deposition acidifies natural and agricultural soils, while a shortage of nutrients (mainly Nr and P) leads to soil degradation (nutrient depletion of the soil) which can be exacerbated by a shortage of micronutrients, leading to loss of fertility and erosion.

This initiative will address the cross-cutting impacts of reactive nitrogen on health, climate change, land management, biodiversity, greenhouse gas emissions, pollution, and to identify links with other nutrient cycles for consideration in the future. These other biogeochemical links include carbon, phosphorus, sulphur, and micronutrients. It builds on ideas and approaches developed under the International Nitrogen Initiative (a sub project of AIMES) and will clarify how the nitrogen theme can be best embedded across Future Earth, setting the agenda for the next five years. The initiative aims to draw together natural sciences and social sciences across Future Earth to co-design with stakeholders an integrated nitrogen approach within Future Earth.

Professor Mark Sutton

Lead ScientistExploring Nitrogen in Future Earth