The UN resolution comes after the year with the highest volume of sargassum ever recorded since systematic scientific measurements began.
SANTO DOMINGO. – From April to October 2025, the Caribbean faced the largest accumulation of sargassum ever recorded in the region, and thanks to an initiative by the Dominican Republic United Nations Environment Assembly specific resolution to address the massive proliferation of this macroalga.
For the Dominican Republic and the countries in the region whose economy is based on tourism, the challenge is to quantify the damage, take advantage of international support, and prepare for a problem that is no longer exceptional.
In 2025, sargassum ceased to be a seasonal phenomenon and became a regional warning sign with global impact.
A historic record in the heart of the Caribbean
According to data from the University of South Florida (USF) oceanographic laboratory, which monitors the so-called Great Atlantic Sargassum Belt using satellite images, more than 37 million metric tons of sargassum were detected floating in the tropical Atlantic, the Caribbean Sea, and the Gulf of Mexico in the spring and summer of 2025.
This is the highest level observed since 2011, the year modern records began. The sargassum belt, which stretches for thousands of kilometers from Africa to the Caribbean, reached an unprecedented , directly impacting the region's island and coastal countries.
The Dominican Republic was no exception. Several coastal areas experienced intense and recurring seaweed influxes, forcing hotels, municipalities, and authorities to deploy continuous cleanup operations, at an approximate cost of US$70,000 each month.
The cost that no one has reported
Despite the magnitude of the phenomenon, there is still no consolidated official estimate of the economic impact of sargassum in the Dominican Republic during 2025, and this lack of information contrasts with the strategic importance of coastal tourism for the national economy.
Previous experiences in the Caribbean offer troubling clues. In past years of high proliferation, countries in the region spent tens of millions of dollars solely on the collection and disposal of sargassum, not including indirect losses such as cancellations, reduced hotel occupancy, or impacts on fishing.
In the Dominican case, the contrast is striking: 2025 was also one of the best years for tourism in terms of visitor arrivals.
However, an uncomfortable question arises for economic analysis: how much greater would that performance have been without the impact of sargassum on beaches exploited by tourism?
The costs of this phenomenon don't always appear in official financial statements. They are diluted among additional operating expenses, municipal efforts, unrecorded work, and reputational damage that is difficult to measure, although real.
Beyond tourism: health and ecosystems
The impact of sargassum goes far beyond the aesthetics of the beaches. As it decomposes, the macroalgae releases gases such as hydrogen sulfide and ammonia, which are associated with respiratory problems, headaches, and negative impacts on coastal communities.
From an environmental perspective, massive accumulation reduces oxygen levels in the water, affecting coral reefs, seagrass beds, and artisanal fishing grounds. In the long term, these effects erode the ecological foundation that supports both tourism and food security in coastal areas.
A turning point
United Nations Environment Assembly adopted the first global resolution on sargassum , promoted by the Ministry of Foreign Affairs of the Dominican Republic along with other Caribbean countries.
The text recognizes sargassum as an environmental, economic and social problem of global scope and tasks the United Nations Environment Programme with preparing technical reports, coordinating scientific research and strengthening international cooperation.
The resolution opens the door to financing, technology transfer, early warning systems and best management practices, key elements for highly exposed countries like the Dominican Republic.
Is the international response coming in time?
The most revealing fact is its timing: the resolution was passed after the most extreme year on record. This reinforces its urgency, but also poses a greater challenge, as scientists warn that the increase in sargassum is linked to changes in ocean currents, increased nutrients, and climate variability.
In other words, the records of 2025 might not be exceptional, but rather part of a new normal.
For the Dominican Republic, sargassum can no longer be treated as an occasional emergency. It is a structural risk that demands clear economic data, inter-institutional planning, and a long-term strategy.
The UN resolution represents a significant diplomatic achievement . The challenge now is to translate that international support into concrete actions before next year's record is broken again.
