This special issue reports the detail of the scientific findings discussed at the international science conference Nitrogen and Global Change, held in Edinburgh on from 11–15 April, 2011. The papers discuss key aspects of reactive nitrogen (N_r) in the environment, including – but not limited to – the relevance of nitrogen for climate change and air quality, for food and energy security and for biodiversity and ecosystem health. While the focus is on Europe and terrestrial ecosystems, papers addressing issues from other parts of the world are represented, as well as contributions discussing the role of nitrogen in freshwater and marine environments. The papers published here in Biogeosciences thus reflect the full breadth of societal challenges related to human perturbation of the nitrogen cycle. As will be seen, the contributions are also broad in nature, covering the full suite of approaches, from measurement and modelling techniques, process understanding, temporal and spatial upscaling, to analysis of policy options and N_r biogeochemistry-economic interactions.

These papers form an accompaniment to the European Nitrogen Assessment, which was launched during the Nitrogen and Global Change Conference, and a series of other products including, earlier special issues, scientific proceedings, the ENA Launch Video and the Edinburgh Declaration on Reactive Nitrogen, as listed in full in the preface of this special issue by the guest editors.