Scientists say climate change is likely to bring more torrential rain, flooding and landslides to Pacific Island countries.
The findings are detailed in a report by the Australian government's Pacific Climate Change Science Programme.
Principal research scientist Kevin Hennessy says the study is the most comprehensive so far for the region and gives 15 Pacific Island countries individually tailored information to help with future planning.
Kevin Hennessy says the region in general is likely to see higher rainfall.
"There are increases of the order of 10 or 20 percent depending on what year in the future and depending on what emissions scenario you look at in the future, but in the worst case high emissions scenario the changes in rainfall and in temperature and sea level are quite high."
Kevin Hennessy says by 2050 coral reefs and their ecosystems are likely to be suffering heavily from the combined effects of higher acid levels, storm damage from more intense cyclones and bleaching.