According to the article, there is still some confusion surrounding the possible effects of global warming on rainfall. Dr. Neelin says: "Precipitation change is much more difficult than temperature change to detect, and requires great precision; the models do not all agree, but the majority of them do."
From the article:
"The research is based on an analysis of 10 global climate computer simulations, from the U.S. National Center for Atmospheric Research, the U.S. National Oceanic and Atmospheric Administration's Geophysical Fluid Dynamics Laboratory, and from Australia, Britain, France, Germany and Japan. In addition to analyzing the computer simulations, Neelin and his colleagues analyzed satellite precipitation data available since 1979, and rain gauge measurements since the 1950s. Over the last 50 years, the Caribbean has experienced a trend of decreased summer precipitation, but not a dramatic one, Neelin said. The computer models predict that will be a continuing trend."
"We can't exclude that the precipitation decrease over the last 50 years is part of a natural cycle, unrelated to global warming," Neelin said. "It is plausible that the decrease is due to global warming, but there is not yet a smoking gun that shows that to be the case."
"The computer climate simulations also agree on the magnitude of drying trends in other regions within the tropics but disagree on where it will occur. The Caribbean/Central-American region is an example where the models agree reasonably well."