Climate change is reducing early wet season rainfall in Puerto Rico and Jamaica

The aim of this research is to assess whether, and to what extent, climate change influenced the Caribbean drought, particularly in Puerto Rico, Jamaica, and the Lesser Antilles, where drought conditions were most severe, using established peer-reviewed scientific methods.

Some of the main findings include:

• Caribbean vulnerability to drought results from the convergence of several compounding factors. Small island territories are naturally limited in freshwater resources and storage, increasing their vulnerability to droughts. 
• Droughts have wide-ranging impacts on agriculture including increasing crop stress, reduced yields, and reduced pasture and forage availability for livestock. Limited land on small islands means that farmers have few alternative options and often resort to expensive imported feed or selling livestock to cope. This can also contribute to food insecurity on islands that already have very high food costs.
• Drought conditions differ across the three regions in terms of rarity, with the rarest low rainfall event of 50 years in Puerto Rico. Conditions were also rare in Jamaica with a 30 year return period.
• Warmer temperatures increase drought severity due to higher evaporation, with this year’s seasonal temperatures observed to have been extremely rare before human-caused climate change. 
• In Jamaica, observations showed a decreasing trend in both May-July actual precipitation and effective precipitation, but the strength of the decrease depends on the dataset.