Blanket bog is a highly distinctive biome restricted to disjunct hyperoceanic regions. It is characterized by a landscape covering of peat broken only by the steepest slopes. Plant and microbial life are adapted to anoxia, low pH and low nutrient availability. Plant productivity exceeds soil organic matter decomposition, so carbon is sequestered over time. Unique climatic requirements, including high year-round rainfall and low summer temperatures, make this biome amenable to bioclimatic modelling. However, projections of the fate of peatlands in general, and blanket bogs in particular, under climate change have been contradictory. Here we use a simple, well-founded global bioclimatic model, with climate-change projections from seven climate models, to indicate this biome's fate. We show marked shrinkage of its present bioclimatic space with only a few, restricted areas of persistence. Many blanket bog regions are thus at risk of progressive peat erosion and vegetation changes as a direct consequence of climate change. New areas suitable for blanket bog are also projected, but these are often disjunct from present areas and their location is inconsistently predicted by different climate models.