Cost-Effective Emission Reductions in Transboundary River Basins : Nitrate Emissions to the North Sea

According to the North Sea Conference, nutrient loads to the North Sea had to be reduced by 50% in 1995 compared to the situation in 1985. This can be achieved by imposing a flat emission reduction rate on all emitting sources, including the river Rhine. However, this will most likely not be the cost-effective solution to such a problem. Therefore, this paper distinguishes between various agricultural sectors (e.g. arable farms on clay/peat soils, arable farms on sandy soils, dairy farms on clay/peat soils, dairy farms on sandy soils, pig breeding farms, and pig feeding farms) and also includes sewage and waste water treatment plants as emitting sources. Regions within the Rhine river basin, one of the largest river basins in Western Europe, have been chosen to match administrative levels at which either agricultural or environmental policies is exercised. The cost-effectiveness analysis has been performed using quadratic cost functions that were assumed to differ for the various sectors, but not for the various regions. Linear transmission coefficients have been used to calculate the impacts of the various sectors in the various regions on the total nitrate load to the North Sea. Under the cost-effective allocation, arable farming on sandy soils in the Netherlands, situated in the downstream area, should reduce their emissions by more than 90%, whereas dairy farms on clay/peat soils in Switzerland, in the upstream region of the Rhine river basin, are required to reduce their emissions by less than 10%. This shows that there are large differences in the required emission reductions between agricultural activities. By implementing the cost-effective allocation, total costs can be brought down by 50% compared to the flat rate emission reduction goal, proposed by the International Rhine Committee. The paper concludes with a discussion on the assumptions underlying this paper and also compares this study with earlier, similar ones