AbstractChanges in vegetation cover due to increasing frequencies of extreme climate events and anthropogenic pressure are already underway; so, predicting the impacts of the near‐future climate will be essential for developing mitigation strategies. We modelled the responses of Brazilian biomes to a future scenario (2070) of steady increases in atmospheric CO₂ levels, adding soil data to better represent the multidimensional space of the environmental suitability of each biome. We also assessed the effects of changes in environmental suitability on the Brazilian network of protected areas and projected those effects on 1 km resolution maps. The area predicted to be affected by future climate change in Brazil and the consequent loss of suitable habitat surface is 2.59 Mkm² – larger than the combined areas of Central America and Mexico – leading the current vegetation to a progressive replacement. We project major changes in the vegetation of the Amazon basin, with the replacement of rainforest by dryer vegetation in the southern and eastern regions of that basin, and the opening of a dry corridor in Pará State. We also project an expansion of 41% of the current caatinga cover in the Brazilian semiarid region, with large losses of suitable habitat surface of the current deciduous forest. Approximately, 37% of the coverage of protected areas in Brazil will be affected – with greater damage to indigenous lands. The speed of current environmental change is now unprecedented for the post‐glacial era, and will almost certainly lead to increased rates of extinction and the collapse of transition ecosystems. We propose the urgent creation of protected areas in regions designed without significant impacts, but contiguous to those that will be more seriously affected by climate change. Those areas will act as refugia preserving biodiversity, ecosystem services, and the cultural heritages of traditional populations.