Human-caused climate change reduced rainfall in Puerto Rico by 9% during May, June and July this year, according to a study involving more than 20 scientists from universities around the world. The research also found that high temperatures caused the little rain that fell in recent months to evaporate more quickly, contributing to the drought affecting municipalities in the southeastern, southwestern and metropolitan areas of the island.
According to research by the international organization World Weather Attribution, Puerto Rico has generally recorded less rainfall than usual throughout the year. A month ago, Gov. Jenniffer González Colón declared a state of emergency over the water crisis, and on Wednesday, the U.S. Department of Agriculture declared a drought disaster in 26 municipalities.
Because of the climate crisis, episodes of water scarcity like those experienced this year are 30% more likely to recur in the coming decades, the report warns. According to the latest data from the U.S. Drought Monitor, 44% of the island is experiencing extreme drought. Jamaica, also in the Caribbean, showed a similar pattern.
The scientists analyzed rainfall during the early part of the rainy season, from May through July, as well as effective precipitation — the amount of rainfall that remains available after evaporation. They found a consistent trend toward drier conditions in Jamaica and Puerto Rico attributable to greenhouse gas emissions, according to the study.
The outlook could be even worse if governments and industries fail to mitigate the climate crisis, the study warned.
Under a scenario of 2.8 degrees Celsius of global warming, precipitation in the Caribbean during May, June and July is projected to decline by an additional 10% in the coming decades, increasing the likelihood of new droughts. The study underscores the need to invest in adaptation measures and infrastructure.
According to the document, the droughts most similar to the one affecting Puerto Rico this year occurred in 1994 and 2015. The 2015 drought was even more similar to this year’s. It was the first time the U.S. Drought Monitor classified conditions in Puerto Rico as extreme drought. Like this year’s drought, the one 11 years ago intensified in May and was concentrated in the eastern part of the island.
Puerto Rico and the U.S. Virgin Islands have experienced widespread drought in 2026 after wetter-than-normal conditions in late winter and early spring, the study says.
“Dry conditions persisted throughout May, June and July, while the region experienced near-record temperatures along with little rainfall. This led to critically low river flows and reduced water availability as reservoir and well levels declined. In Puerto Rico, declining surface water and groundwater supplies have led to water rationing for agricultural users in the south-central and southwestern regions, as well as for residents in parts of the San Juan metropolitan area,” the report states.
The low-rainfall phenomenon recorded on the island is so unusual that, according to the study, it occurs once every 50 years. Although there have been reports in recent weeks about El Niño, the study found no strong correlation between the phenomenon and declining precipitation in the Caribbean.
“El Niño has been blamed for the current drought in the Caribbean, but our research shows that during the first part of the rainy season, from May to July, human-caused climate change is the primary driver,” said Theodore Keeping, a researcher specializing in extreme weather events.
“We found that global warming — driven primarily by the burning of fossil fuels — has reduced rainfall during the first part of the rainy season, turning dry periods that should be manageable into severe droughts,” he added.
The Caribbean: One of the World’s Most Water-Stressed Regions
The drought has spread across the Caribbean. The U.S. Virgin Islands, Saint Lucia, Saint Vincent, and Grenada are among the islands experiencing the same problem.
The Caribbean is one of the world’s most water-stressed regions because of water scarcity, according to the study. Water stress occurs when more water is needed than is available.
Places such as Antigua and Barbuda, Barbados, and Saint Kitts and Nevis are among the 36 most water-stressed countries in the world, with an average of 540 cubic meters of freshwater per person, according to the World Bank. Puerto Rico has 2,205 cubic meters of freshwater resources per person.
According to the World Bank, the minimum threshold for countries or territories to avoid water stress under normal conditions is 1,700 cubic meters of freshwater per person.
The Caribbean has fragile water infrastructure because of its dependence on rainfall to replenish groundwater and rivers. Across the region, deregulation and overexploitation of groundwater sources further limit access to drinking water during droughts, the report says. Aging drinking water infrastructure, along with leaks, inaccurate metering, inadequate management and water theft, reduces the amount of water available to users.
The study also highlights that an average of about 46% of drinking water is lost in the Caribbean. In Puerto Rico, that figure rises to 60%, according to official documents and independent studies.
“In Puerto Rico, Jamaica and the U.S. Virgin Islands, families and farmers are suffering the effects of strict water rationing as they watch major reservoirs dry up,” said Jhordanne Jones, a professor of tropical climatology at the University of Pennsylvania. “Our islands have contributed very little to this problem, but our people are suffering the impacts of the world’s addiction to fossil fuels.”
Soils Are Getting Drier
The study also found that soils, particularly along Puerto Rico’s southern coast, have dried out because of high temperatures and water stress on vegetation. In the coming decades, water stress on crops on the island will increase as a result of higher temperatures, the experts projected.
“In Puerto Rico, reservoir, river and groundwater levels have declined considerably, leading to water rationing for agriculture, including restrictions of up to three days per week in some parts of the southwest,” the study says. “Some wells have reached critical levels, while reduced river flows have affected irrigation and local water availability. Farmers have reported cracked, moisture-deficient soils, crop stress and delayed growth, premature fruit ripening, and losses in coffee, citrus, plantains, bananas, breadfruit and other fruit trees. Deteriorating pastures have reduced forage availability, increasing reliance on purchased feed and depleting hay reserves,” the document adds.
The southern part of the island is more prone to water stress because rainwater infiltration is lower.
However, droughts are increasingly affecting the island’s central region, which is also experiencing lower rainfall and reduced rainwater infiltration, as well as greater evapotranspiration and limited groundwater availability.
Grassland Fires Are Increasing
Dry conditions have also increased the risk of grassland fires. In July alone, at least 300 fires were recorded on the island, affecting agricultural areas and infrastructure. If the drought persists into the fall, along with low rainfall and high temperatures, that number could rise. The newspaper Metro Puerto Rico reported that from January through August this year, the number of grassland fires had reached 2,682 — 74% more than the previous year, when there were 1,540.
This translation was generated with the assistance of AI and reviewed by our editorial team to ensure accuracy and clarity.
