Future Scenarios of Nitrogen in Europe

The future effects of nitrogen in the environment will depend on the extent of nitrogen use and the practical application techniques of nitrogen in a similar way as in the past. Projections and scenarios are appropriate tools for extrapolating current knowledge into thefuture. However,these tools will not allow future system turnovers to be predicted. Approaches• In principle, scenarios of nitrogen use follow the approaches currently used for air pollution,climate ,or ecosystem projections. Short term projections (to 2030) are developed using a ‘baseline’ path of development,which considers abatement options that are consistent with European policy. For medium-term projections (to 2050) and long-term projections, the European Nitrogen Assessment (ENA) applies a ‘storyline’ approach similar to that used in the IPCC SRES scenarios. Beyond 2050 in particular, such story lines also take into account technological and behavioral shift s.Key findings/state of knowledge• The ENA distinguishes between driver-oriented and effect-oriented factors determining nitrogen use. Parameters that cause changes in nitrogen fixation or application are called drivers. In a driver-based approach, it is assumed that any variation of these parameters will also trigger a change in nitrogen pollution. In an effect-based approach, as the adverse effects of nitrogen become evident inthe environment, introduction of nitrogen abatement legislation requiring the application of more efficient abatement measuresis expected. This approach needs to rely on a target that is likely to be maintained in the future (e.g.human health). Nitrogen abatement legislation basedon such targets will aim to counter any growth in adverse environmental effects that occur as a result of increased nitrogen application.• For combustionand industry, technical fixes forabatement are available. Allscenarios agree in projecting a decrease in NOx emissions.Yet agricultural nitrogen use is expected to remain the leading cause of nitrogen release to the environment, as options to reduce emissions are limited. Thus, major changes will occur only if the extent of agricultural production changes, which may possibly be triggered by decreasing population numbers in Europe.The scenarios presented here project modest changes in NH 3 and N 2 O emissions, or nitrateleaching, but do not agree on the direction of these changes.•Agricultural activity (and thus nitrogen loads to the environment) may decrease strongly if the European population adopts a healthier‘low meat’ diet leading to lower nitrogenlosses related to animal husbandry. Change to a ‘healthy diet’ across the EU, which consists of 63% less meat and eggs, would reduce ammonia emissions from animal production by 48%. However, if an agricultural area previously used for animal feed production is utilized for biofuel crops, additional nitrogen fertilizer maybe required, which will partially offset reductions of nitrogen leakage to the environment. Major uncertainties/challenges• International trade in nitrogen-containing goods (agricultural as well as industrial) represents a key uncertainty and is difficult to project. Estimating the demand for such goods for Europe alone may not at all reflect European production and related environmental effects. The industrial use of nitrogen is alsovery poorly understood, but it is expected to continue to grow considerably. The respective environmental impacts of such products cannot be clearly discerned from statistical information.Recommendations• Scenarios need to be continuously updated in terms of economic, technical, and societal trends to reflect improved understanding of these factors. Using nitrogen budgets as tools could improve the consistency of scenarios.JRC.DDG.H.2-Climate change and air qualit