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 the future. However, these tools will not allow future system turnovers to be predicted

Uncertainty in Modeling Regional Environmental Systems: The Generalization of a Watershed Acidification Model for Predicting Broad Scale Effects

Policies aimed at the alleviation of negative environmental impacts have increasingly been based on predictions made with models of the environmental systems involved. The usefulness of these models is limited by many uncertainties, e.g., is the complexity of a system properly reflected in the model structure and chosen aggregation-level? Is the data used in the model representative of the system? Is the temporal and spatial scale used in the model appropriate for understanding the system's behavior? The combination of these uncertainties may lead to unexpected results. This study identifies key factors determining watershed responses to acid deposition in different regions, using the RAINS Lake Acidification Model. The study aims at: -- Providing a method for defining a region such that environmental policy directed at alleviating watershed acidification will become more suitable for the large scale management of surface water quality. -- Depicting regional characteristics that allow for the usage of a less detailed and thus more aggregated model. -- Providing an operational concept of critical loads for policy insight into watershed quality as a function of the spatial zoning of watersheds. The results of the study are: -- The 5-step method of flexible zoning introduced in this study, allows for a probabilistic investigation of the compatibility between models and available spatial data. -- The calibration of models to previously defined regions may be of limited use for policy purposes because predictions of environmental effects (i.e., watershed acidification) as a result of changing deposition patterns over large regions may be error prone. -- Cumulative distributions of model predictions about the acidification of watersheds should be used to assess critical and target loads for broad regions

A Model for Analyzing Lake Water Acidification on a Large Regional Scale. Part 2: Regional Application

The International Institute for Applied Systems Analysis is developing a computer model which can be used by decision makers to evaluate policies for controlling the impact of acid rain in Europe. As part of this task, a dynamic model has been developed for describing the processes leading to acidification of surface waters. The modeling philosophy is to use a simplified approach, which is warranted for a broad geographical scope. The simulation model is constructed of several modules, each of them providing an overview of a particular aspect of lake acidification. Because of the very sparse input data available on a large regional scale, a new method is applied for estimating unknown inputs. The model is calibrated to presentday conditions by selecting input combinations from feasible ranges. Monte Carlo techniques are used to determine those combinations of inputs that produce the observed present-day lake acidity distribution, when the model is driven by a specified deposition. The ensembles obtained in the calibration procedure for each lake region are used for the scenario analysis. The usefulness of the method is compared with respect to the traditional a prtori parameter estimation technique. Results of sensitivity and uncertainty analysis are used to compare model predictions with observed values and to indicate where changes in the distributions of model parameters will affect predictions the most

Environmental Conflicts: The Case of Acid Rain in Europe

The acid rain problem is transboundary in nature: sulfur emissions in one country may lead to deposition of sulfur in a receptor country. A policy conflict may arise in estimating the damage at some receptor due to the various pollutant sources. This paper first reviews the international policy context that led to the development of the Regional Acidification Informational and Simulation (RAINS) model. The model computes sulfur emissions, transport and deposition which is then transferred into soil and lake acidity. The model is an interactive tool designed to assist policy makers in evaluating the effect of the control measures related to sulfur emissions. A mathematical description of the model is provided followed by a set of objective functions to be introduced within the RAINS model. The current interactive usage of RAINS will be extended with the possibility for the decision maker to progressively define objectives and set constraints in order to obtain an optimal policy

Critical load exceedances under equitable nitrogen emission reductions in the EU28

The ecosystem area in the 28 states of the European Union (EU28) for which eutrophication critical loads are exceeded is investigated under the revised National Emission Ceiling Directive (NECD) and under alternative scenarios whereby reduction efforts are shared equitably among Member States. The focus is on nitrogen oxide (NOx) and ammonia (NH3) emission reduction policies that ensure that the total EU28 emission reduction target for 2030 under the NECD is achieved, but by equity-based emission reductions for each Member State. A gradual reduction of emissions of nitrogen in the EU28 is assessed by imposing ever lower common maximum densities for emissions (a) per unit area of a country (areal-equity) (b) per capita of a country's population (per capita-equity), and (c) per euro (€) of a country's GDP (GDP-equity). The NECD aims at a reduction of EU28 emissions of NOx and NH3 of 63% and 19%, respectively in 2030, compared to base year 2005. Under these reductions, about 67% of EU28 ecosystem area remains at risk of adverse effects of nitrogen deposition. We demonstrate that reducing N emissions subject to GDP-equity among EU28 Member States could have reduced that area at risk to about 61%. The application of areal and per capita-equity does not lead to significantly different ecosystem areas at risk when compared to NECD

Acidification in Europe : A Simulation Model for Evaluating Control Strategies

RAINS (Regional Acidification Information and Simulation) is an integrated model of acidification in Europe designed as a tool for evaluating control strategies. It is currently sulfur-based, but is being expanded to include nitrogen species. Emphasis of the model is on the transboundary aspects of the acidification problem. Model computations are performed on a personal computer. Linked submodels are available for SO2 emissions, cost of control strategies, atmospheric transport of sulfur, forest soil and groundwater acidity, lake acidification, and the direct impact of SO2 on forests. The model can be used for scenario analysis, where the user prescribes a control strategy and then examines the cost and environmental consequences of this strategy, or for optimization analysis, in which the user sets cost and deposition goals, and identifies an "optimal" sulfur-reduction strategy. Preliminary use of the model has pointed to 1. the importance of examining long-term environmental consequences of control strategies, and 2. the cost advantages of a cooperative European sulfur-reduction program

Chemical footprints of anthropogenic nitrogen deposition on recent soil C : N ratios in Europe

Abstract. Long-term human interactions with the natural landscape have produced a plethora of trends and patterns of environmental disturbances across time and space. Nitrogen deposition, closely tracking energy and land use, is known to be among the main drivers of pollution, affecting both freshwater and terrestrial ecosystems. We present a statistical approach for investigating the historical and geographical distribution of nitrogen deposition and the impacts of accumulation on recent soil carbon-to-nitrogen ratios in Europe. After the second Industrial Revolution, large swaths of land emerged characterized by different atmospheric deposition patterns caused by industrial activities or intensive agriculture. Nitrogen deposition affects soil C : N ratios in a still recognizable way despite the abatement of oxidized and reduced nitrogen emissions during the last 2 decades. Given a seemingly disparate land-use history, we focused on ~ 10 000 unmanaged ecosystems, providing statistical evidence for a rapid response of nature to the chronic nitrogen supply through atmospheric deposition

Harmonizing European land cover maps.

Environmental Biology - ol