We studied the consequences of projected climate change on biome distribution in South America in the 21st century by forcing a potential vegetation model with climate scenarios from 15 climate models for two emission scenarios (A2 and B1). This analysis was carried out for the savanna and tropical forest biomes, which are the predominant biomes in tropical South America. In both scenarios, the results indicate reduction of tropical forest cover areas which would be replaced by savannas. This reduction of tropical forests increases with the time through the end of the 21st century, mostly over southeastern Amazonia. Considering the biome changes from current potential vegetation in the case when at least 75% of the calculations agree on the projected biome change (consensus), the decrease of the tropical forest area in South America is 3% for the period 2020–2029, 9% for 2050–2059 and 18% for 2090–2099 for the A2 emission scenario.