Mexican Caribbean Has Lost More Than 70% of Its Corals, UNAM Scientist Warns

Puerto Morelos, Quintana Roo — The Mexican Caribbean has lost more than 70% of its coral cover since the early 1980s, a decline driven by unchecked coastal development, wastewater pollution and, more recently, extreme ocean heat, a UNAM reef scientist has warned.

Lorenzo Álvarez Filip, a researcher at the National Autonomous University of Mexico’s (UNAM) Institute of Marine and Limnology Sciences, assigned to its Reef Systems Unit in Puerto Morelos, said the region’s reef crisis is not a sudden emergency but the result of decades of accumulating pressure.

He spoke during a colloquium on climate change, where he laid out the scale of the damage recorded along Quintana Roo’s coast over the past four decades.

A gradual decline, not a sudden collapse

Álvarez Filip said the deterioration began long before global warming emerged as the dominant threat, tracing it to the coastal construction boom of the 1970s and 1980s and the runoff and sewage that followed.

“The situation isn’t that it suddenly went bad now. It is something gradual that we have been watching over the last three or four decades, as the amount of coral and the health of the reefs in Quintana Roo have been declining,” he said.

That decline, he added, “was not necessarily triggered by climate change, because we are talking about something that started in the 70s or 80s with coastal development, when all the pressures coming from land toward the sea began.”

Heat waves delivered the latest blow

Climate change has compounded that historical damage. Álvarez Filip said rising temperatures culminated in 2023 and 2024 in severe marine heat waves that triggered mass mortality events in coral colonies already weakened by pollution and development.

“Climate change has been increasing the intensity of heat waves, and temperature stress has been growing over time. We reached a point in 2023-2024 with very strong heat waves that had very negative effects on reefs that were already degraded and battered, and we had very large coral mortality events,” he said.

Assessing the accumulated toll, the researcher said the loss is now so extensive that each new episode is harder to absorb.

“In recent decades, from the early 1980s to now, we have lost more than 70% of the corals we had. Those recent loss percentages don’t feel so large because we had so little left, but when we start losing that little, it is truly desperate, because we are wiping out the little that remains,” he said.

El Niño and unregulated development loom

The outlook for the coming years is delicate, Álvarez Filip said. Unregulated urban growth along the coast continues, and global weather patterns such as El Niño could bring renewed thermal stress and coral die-offs in 2026 and 2027.

He called for urgent action on strict environmental management and controls on pollutant discharges to protect the few reef cores still standing and give them a chance to recover.