Much progress has been made in understanding future trend development over the last years. Governments and international bodies are increasingly attempting to assess ex-ante the impact of their policy proposals. In the SENSOR project, environmental sustainability is assessed by answering a set of policy relevant questions likely to affect goods and services provided by land. The answer is complex and the assessment of future options is very sensitive to scale, how far ahead in time is being considered, and whether the assessment addresses local, regional or global concerns. The relationships between components of land use and the response of environmental indicators are not necessarily linear and assessing impacts at a European scale implies to use multi-scale sources of data of uneven quality across countries, which in turn creates constraints when interpreting the results at different spatial levels. This chapter describes the methodology that was designed to undertake the environmental impact assessment in the SENSOR project. It presents the rationale behind the selection of indicators for environmental sustainability and addresses how environmental indicators can be derived from outputs of sectoral models, using two selected environmental indicators as an example. General issues connected to the modelling of environmental impact at pan-European level are discussed.