Marine scientists have alerted that nearly half of the world's beaches may vanish by the end of the century due to rising sea levels and human development. This erosion threatens coastal ecosystems, biodiversity, and economies reliant on tourism and fishing. The warning came from Uruguayan expert Omar Defeo at a symposium in Montevideo.
During the opening of the FAPESP Day Uruguay symposium on November 13 in Montevideo, Omar Defeo, a professor at Uruguay's University of the Republic, highlighted the accelerating loss of global beaches. "Almost half of the beaches will disappear by the end of the century," Defeo stated. He emphasized the need for collaboration among Uruguay, Brazil, and Argentina to manage shared coastal resources.
Defeo described the coastal system as three interconnected zones: the dune above the high tide mark, the beach face exposed at low tide, and the submerged foreshore where waves break. These areas exchange sediment bidirectionally, with dunes buffering storms. "When urbanization eliminates the dune, the result can be the destruction of seaside homes," he explained.
A study led by Brazilian researcher Guilherme Corte, involving Defeo's team and FAPESP-supported scientists, surveyed 90 sites across 30 beaches on São Paulo's northern coast. Published in Marine Pollution Bulletin, it found that high numbers of beachgoers most severely reduce species richness and biomass, particularly in submerged zones. Construction on sand and mechanical cleaning also diminish biodiversity, while urban areas see higher abundance of opportunistic species like polychaetes. "Human impacts aren't restricted to the place where they occur," Defeo noted, pointing to effects rippling across zones.
Another global analysis of 315 beaches, published in Frontiers in Marine Science, revealed that one-fifth face intense to severe erosion. Factors include sea level rise, shifting wind patterns, wave changes, and human activities, especially on reflective and intermediate beaches.
The symposium's oceanographic session, moderated by Marcelo Dottori of the University of São Paulo, included inputs from Cristiana Seixas of the State University of Campinas and Natália Venturini of UdelaR. Attendees at the opening included Alvaro Brunini of Uruguay's ANII, Marcio de Castro and Raul Machado of FAPESP, and Brazil's ambassador Marcos Leal Raposo Lopes.