Their work is published in the Proceedings of the National Academy of Sciences ( PNAS ) journal . • almost all the climate models underestimated the current amount of Amazonian rainfall , because they are unable to capture the peculiarity of the geography of South America . • sections of rainforest in the eastern part of the Amazon , which is currently wet all year round , are likely to become " seasonal forests " which have a wet and a dry season . • but there will probably still be enough rainfall during the year not to turn it into savannah ( dry , flat grassland ) . • the Western part of Amazonia is likely to keep a climate and pattern of rainfall conductive to maintaining a rainforest , although the drier margins in the north and south may not .