UNAM Warns of Imminent Glacier Loss in Mexico

UNAM warns that Mexico’s last remaining glaciers could disappear within the next five years. Glaciers are important sources of fresh water, and as they shrink, pressure on dams and aquifers increases, many of which are already facing overexploitation.

“The reduction of the vital water they provide affects local climate, agriculture, and the availability of this resource for human consumption. This is why we must plan adaptation measures for the new conditions,” explains Hugo Delgado, Researcher of the Institute of Geophysics, UNAM.

Glaciers are masses of ice that persist throughout the year, even during the warmest seasons. They form when snow that falls in a cold region does not completely melt but instead accumulates year after year. Over time, these layers of snow become compacted and turn into ice, forming masses that can range from tens to hundreds of meters thick, as seen in the polar regions.

The world’s largest glaciers are found in Greenland and Antarctica. However, there are also major reserves in other mountain ranges at all latitudes, from polar regions to tropical areas such as the Andes, or even Mexico.

According to Lorenzo Vázquez, Researcher of the Institute of Geography, UNAM, sixty years ago glaciers existed on Mexico’s three highest mountains: Pico de Orizaba, Popocatepetl, and Iztaccihuatl, all rising above 5,000 m. Due to their altitude and cold climate, these mountains once housed permanent ice masses. However, in recent decades these glaciers have suffered severe degradation due to climate change.

Since the first inventory in 1960, scientists documented a clear trend of glacial reduction, both in area and volume. This decline accelerated significantly starting in the 1990s. At the Popocatepetl, the volcanic eruption that began in 1994 sped up the glacier’s disappearance because of the heat and volcanic ash. Combined with global warming, this led to its complete extinction in 2025.

On Iztaccíhuatl, only fragments of three glaciers remain today, together adding up to just 12ha (10% of their original size). These glaciers are now extremely thin, just a few meters thick, and are expected to disappear entirely in about five years.

Pico de Orizaba, being the highest peak, has preserved its glaciers somewhat better. In 1960 it had roughly 204ha of ice distributed across several glacier tongues. Today, only about 37ha remain (18% of the original), and they are shrinking rapidly, Vázquez emphasized.

Francisco Estrada, Coordinator of the Climate Change Research Program, UNAM, stresses that glacier loss is directly linked to climate change, especially because in the coming years global temperatures will exceed the threshold scientists warned should not be crossed.

Since 2023, global temperature has risen above 1.5°C, and in Mexico’s specific case, the national average temperature has increased by 1.8°C from the pre-industrial period to 2024. This means Mexico’s warming rate is higher than the global average. “While global temperatures are rising by about 2°C per century, Mexico’s rate is closer to 3.2°C per century,” Estrada explained at an academic forum earlier this year.

The accelerated loss of glaciers has direct consequences for the population. Seventy percent of the planet’s fresh water is stored in ice. Although Mexico’s glaciers are much smaller than those in other regions, their disappearance still carries serious local impacts.

Because glaciers are natural ice reservoirs, their reduction means there will be less fresh water available in the future. This especially affects communities near the mountains, which depend on meltwater to sustain streams and springs. As these sources dwindle, pressure increases on other reserves such as dams and aquifers, many of which are already overexploited.

Additionally, glaciers play a critical ecological role by regulating the temperature and humidity of high-mountain ecosystems and stabilizing watershed systems. Their disappearance disrupts these dynamics and threatens endemic species that rely on those conditions.