Changing climate and land use appear to importantly affect the biosphere by way of impacts on fire regimes. Feedback effects on climate and air quality are likely through emissions of trace gases, aerosols, and particulates that affect radiation budgets, stability of the troposphere, and biogeochcmical and hydrologic cycles. Paleorecords of biomass burning are available in the form of stratigraphic charcoal inlake and mire deposits and fire scars on trees. When taken together with recent emissions data from experimental burns and wildland fires they hold promise for estimation of how changing fire regimes may be affecting atmospheric composition, We synthesize existing evidence for effects of global change on fire regimes for each of the major biomes. Fire regimes vary in their sensitivities to changing climate, with woodland/savanna types and boreal forest among the most sensitive. Emissions have greatly increased with changing human influences in some vegetation types (temperate and some low-latitude biomes) and decreased in others (temperate pine forests). Some biomes, including boreal forests, hold promise for rather detailed reconstructions of past emissions. We recommend that future efforts focus on those regions where the importance of fire and availability of paleodata are greatest. ©by the Ecological Society of America. Abstract reproduced by permission.