This publication examines the risks associated with the release of excessive nitrogen into the environment (climate change, depletion of the ozone layer, air pollution, water pollution, loss of biodiversity, deterioration of soil quality). The report also examines the uncertainty associated with the ability of nitrogen to move from one ecosystem to another and cause "cascading effects". In addition to better management of nitrogen risks at the local level, there is a need to consider the global risks associated with the continued increase in nitrous oxide concentrations and to prevent excess nitrogen in all its forms by developing cost-effective strategies for all its sources. Other than the reduction of nitrogen pollution, this report provides guidance on the use of nitrogen policy instruments and how to ensure coherence with objectives such as food security, energy security and environmental objectives.