More on integral nitrogen
Humans have doubled the annual rate of nitrogen fixation (transformation of inert atmospheric molecular nitrogen, N2, to reactive forms of nitrogen, Nr) in the past 150 years. Reactive N is now accumulating in the environment on all local and regional scales. Nr accumulation contributes to many contemporary environmental problems, including eutrophication, ozone formation and acidification. During the last few decades, production of Nr by humans has been greater than production from all natural terrestrial systems.
Reacted nitrogen problems act at the international level
Human activities have also increased the mobility of reactive N within and between terrestrial and aquatic ecosystems, and the atmosphere. While most of the reactive N emissions occur locally in the terrestrial system, the influence of these emissions spreads regionally and globally as it moves through water and air across political and geographic boundaries. Hence, the problems associated with reactive nitrogen (Nr) act for a large part at the international level. This dossier “Global integrated nitrogen” summarizes the work at PBL on global studies related to the use and distribution of reactive nitrogen. PBL is involved in European (the EU-Integrated Project NitroEurope, the European Nitrogen Assessment) and global studies (the Unesco project Global Nutrient Export from Watersheds). In addition, PBL supplies data on reactive nitrogen emissions to many international studies
Involved model
This work involves the Integrated Model to Assess the Global Environment (IMAGE). In particular, IMAGE simulates global reactive nitrogen emissions to air, groundwater and surface water. Details on the model parts with relevance for reactive nitrogen can be found in chapter 8 of the recent book “Integrated modelling of global environmental change. An overview of IMAGE 2.4”.
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