Browsing by Subject "Treibhauseffekt"

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Qualitativer Vergleich von Modellen zur Bewertung von Klimaschutzmaßnahmen in Europa unter besonderer Berücksichtigung der Landwirtschaft
(2006) Vabitsch, Anna Maria; Zeddies, Jürgen
Agriculture in Europe is responsible for a considerable fraction of greenhouse gas emissions. Methane, nitrous oxide and carbon dioxide emissions from agricultural sources account for about 10% of the total European greenhouse gas emissions. The contribution that agriculture can and should make to the achievement of the agreed European goals for emission reductions has to be assessed. The aim of this study is to analyse the possibilities and conditions for greenhouse gas mitigation in the agricultural sector in comparison to other economic sectors. It addresses the question of how meaningful and efficient it is to reduce greenhouse gas emissions from farming. A review of the literature showed that various measures for emissions reductions are available for agriculture as well as for the other sectors. In order to assess the efficiency of these mitigation measures, a quantification of abatement costs is necessary. For this purpose, economic-ecological models were chosen which were developed mostly for political advice and analysis. A detailed analysis and assessment of the chosen models was carried out in order to evaluate the model results. The comparative assessment of model results arrives at the conclusion that there is presently no model available that satisfies all the requirements demanded of an environmental indicator for climate policy. For this comparison of models, a selection of representative models was described and analysed in detail. The following models were chosen for the detailed analysis and assessment: POLES, MERGE, EPPA-EU, PRIMES / GENESIS, RAINS / GAINS, CAPRI, AROPA GHG and RAUMIS. They were differentiated between highly aggregated models which represent the global economy with its impacts on the climate system and, in contrast, disaggregated models which focus on a single sector and/or region. Two categories of model structures were observed: general and partial equilibrium models based on the neo-classical economic theory of perfect markets and, on the other hand, optimisation models which were solved by the maximisation of (regionally weighted) profit and benefit. An important feature which distinguishes between the models is the sectoral and material resolution. Aggregated energy models are commonly used, most of which not only reproduce the energy sector, but also the other sectors. However, they only account for energy-related CO2 emissions. These models provide important information on the most relevant emitting sector (energy) and the most important greenhouse gas (CO2), but they neglect the presence of the other Kyoto-gases and the possibilities of an integrated approach for emission reductions. The results of assessments of mitigation potential in the agricultural sector using energy models are incomplete because the relevance of non-CO2 emissions and their possible contribution to overall emission reductions are disregarded. As a second focus models of the agricultural sector were analysed and assessed. These models describe the agricultural production process with a high degree of resolution and determine specific mitigation costs of single measures and options. Additionally, some of these models assess the interactions and effects of simultaneously reducing emissions of different greenhouse gases. However, the problem still exists that results from models of different sectors are not comparable with one another. The main reasons for this are the varying model assumptions and the specific conditions. A method to resolve this dilemma is provided by the models that integrate top-down and bottom-up elements in one model framework. This means that several sectors and countries are simultaneously modelled (top-down) but detailed information on specific gases and mitigation options is integrated as well (bottom-up). Using this procedure, the comparison of different sectors is possible and sector-specific accuracy in the definition of abatement costs, for instance, is also achieved. This procedure is most advanced in the case of integrated assessment models. This approach aims to account for as many aspects as possible of one environmental problem as well as for all its interactions and impacts on other environmental goals. At present, these very complex model systems are most readily applicable to find solutions for the optimal spatial, temporal and material allocation of mitigation measures and investment. The significance of these model results is, of course, also dependent on the available database and on the assumptions made. These models come to the conclusion, among other things, that the integration of agricultural greenhouse gas emissions into a holistic mitigation approach may provide a significant reduction in mitigation costs. Despite the high level of uncertainties regarding the model results, it can be concluded that the agricultural sector should definitely contribute to achieving the agreed emission reductions.