Three Scenarios for Land-Use Change: A Case Study in Central Europe.
The study presented in this paper is part of the Regional Material Balance Approaches to Long-Term Evironmental Policy Planning Project at IIASA. This project aims at studying the flow of four heavy metals (cadmium, zinc, lead, and arsenic) with particular focus on soils. The combination of load, soil characteristics, land use, and land management, including plant types grown and agrochemical applications, determines the fate of stored heavy metals. Heavy metals may further accumulate in the soil or they may be remobilized and enter the food chain via plant uptake or via groundwater. Land use and land management have an impact on the load of heavy metals because certain agrochemical inputs (phosphate fertilizers, sewage sludge, manure) contain heavy metals as impurities. Certain land-management practices also influence the soil characteistics that determine whether heavy metals accumulate or are available in their mobile form. The proect area includes the northern part of the Czech Republic (Bohemia and Moravia), southwesern Poland (Upper and Lower Silesia), and most of former East Germany (Sachsen, Sachsen-Anhalt, Brandenburg, and Thueringen). The project area covers about 180,000 sq. km, parts of which are highly industrialized and densely populated. Extensive atmospheric impact of pollutants from coal burning and other industrial activities has resulted in chemical deterioration of soils. Heavy metals have accumulated in the soils over the past few centuries. In spite of this pollution in certain areas, the project area as a whole is important for agricultural production, with half of its land use devoted to agriculture. In 1992, utilized agricultural area (UAA) accounted for 10 million hectares (54% of total land area), with nearly two-thirds of UAA used as arable land and the remainder used as as grassland or meadows. Six million hectares (32%) are covered by forest and the remaining 2.5 million hectares (14%) fall into the category "other land," which consists mainly of urban and mining land. Land-use scenarios have been developed to help assess possible effects of accumulated heavy-metal pollution in the region. Because future land use and agriculture are highly uncertain, we have developed three radically different scenarios, all of which are possible but not equally probable. The first scenario (increase in wooded area) anticipates liberalization and abolition of subsidies in the agricultural sector and increases in demand that are too small to enable farmland in marginal areas to remain competitive. Large areas will be taken out of production and turned into forest or used for other nonagricultural purposes. Scenario 2 (alternative agricultural products) assumes a shift from food roduction to nonfood production, mainly biofuel, and incentives for extensification of agricultural production. The third scenario (Europe as food exporter) foresees increasing demand and rising world market prices for agricultural products, triggered by increasing wealth combined with environmental constraints in China and Southeast Asia. This paper describes these three scenarios, which were constructed for the period 1995-2050. Section 2 presents the factors that influence land-use development and describes historical land-use changes in Europe and the countries of the project area. Developmensts in the agricultural sector, which are considered to be of particular importance for land-use changes in the European context, are discussed in Section 3. The discussion includes recent developments in Poland, the Czech Republic, and Germany, but also trends in the Common Agricultural Policy (CAP) of the European Union (EU) and possible impacts of global agricultural markets on European agriculture. Section 4 presents a general introduction to scenario construction; introduces the goals and key questions for the three scenarios constructed for the project area of this study; and presents, discusses, and compares the three scenarios. Conclusions are presented in Section 5.
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