The natural capacity of the environment to absorb higher levels of pollution, particularly in densely populated metropolitan areas, will become the limiting factor for the unconstrained use of fossil fuels. Local environmental problems are of greater concern to local decision makers than global problems and therefore will have a greater near-term impact on policy. In the developing world indoor air pollution is an urgent environmental problem. A shift away from cooking with wood in open fireplaces will reduce indoor pollution levels currently estimated to be 20 times higher than in industrialized countries. A second urgent problem is the high concentration of particulate matter and sulfur dioxide in many urban areas. Regional air pollution could also prove problematic, especially in the rapidly growing, densely populated coal-intensive economies of Asia. Without abatement measures, sulfur emissions could cause serious public health problems and subject key agricultural crops to acid deposition 10 times sustainable levels. Agreement that local environmental impacts will take precedence over global change was unanimous in both the regional polls and the detailed regional reviews. It is important, however, not to see the two as separate issues, and to explore strategies that achieve simultaneous progress on both fronts. Improved efficiency and cleaner energy systems (decarbonization) are the key components of the strategy suggested by the global analysis. This emphasis on more efficient and cleaner energy systems as a resilient environmental strategy was invariably echoed in the regional reviews. If policies and investments correspond to the ecologically driven Case C, both regional and local issues are addressed together. But if regional pollution controls are add-ons to fossil-based energy systems such as in Case B, any future reductions in CO2 emissions only become increasingly remote and difficult. Hence, a number of regional reviews emphasized the need for a long-term perspective and anticipatory RD&D and technology policies to best prepare for future contingencies. After all, climate change is a long-term environmental issue and responses must be prepared in time to prevent disruptions and high costs. This also means that care must be taken not to reduce the flexibility of longer-term energy systems through prematurely locking in existing technologies or exclusively using ``add-on'' environmental fixes.