This paper presents results of an assessment of the linkages between regional air pollution and climate change in Europe (the AIR-CLIM Project). The main research tool was an integrated modeling framework and the main product was a consistent set of long-term scenarios covering Europe between 1995 and 2100. Scenarios consisted of trends in emissions, acid deposition, nitrogen deposition and climate change. Critical loads and critical levels were used to assess the impacts of deposition to forest soils and a new analogous concept of "critical climate change" was developed to assess the impacts of climate change. Taking into consideration the limitations of the scope and models used in the study, preliminary conclusions were: (1) regional air pollution and climate change may be fairly weakly coupled in the natural environment, i.e. climate change was not found to have a large impact on the sensitivity of forest ecosystems to regional air pollution, nor on the distribution of deposition; nor did regional air pollution (in the form of sulfate aerosols) have a significant impact on climate change in Europe; (2) however, regional air pollution and climate change may be strongly coupled in the "policy" environment. It was estimated that virtually all of Europe at mid-century might be affected by either regional air pollution or climate change, or both, and this will require a strong policy response. Moreover, the indirect effects of climate policies were found to reduce the costs of controlling air pollution emissions by more than 50%, suggesting a strong potential financial linkage between policies to reduce greenhouse gas and air pollution emissions. © 2002 Published by Elsevier Science Ltd.