The death of the last glaciers in Mexico

Mexico has just five glaciers left, spread over two mountains: Iztaccíhuatl and Pico de Orizaba. Covering less than one square kilometer of ice, none of them are likely to exist by 2050, according to experts, who blame global warming for this rapidly disappearing source of freshwater

The death of the last
glaciers in Mexico

Iztaccíhuatl-Popocatépetl National Park (State of Mexico) - 04 Jun 2021 - 12:19 UTC

The Ayoloco glacier was once 200 meters thick, an icy colossus dragging rocks through its slow path down the slope. When you ascend to the 4,700-meter point of the Iztaccíhuatl volcano in central Mexico today, all that remains are the deep grooves it carved and a wall of old ice. The awesome force of its weight, dating back millennia, is gone.

Two researchers from the National Autonomous University of Mexico (UNAM) are now trying to affix a metal plate into one of those ancient grooves. They coat it with glue and secure it with screws. They don’t want it to fall down in the next storm. “This plaque is in memory of Ayoloco, to remind us it was here,” explains glaciologist Hugo Delgado. “And that it receded until it disappeared in 2018 because of climate change linked to human activity.”

The disappearance of this key water source cannot be reversed, and soon ice-free slopes and stones scattered like bones are all that will be left of Mexico’s once plentiful glaciers

This geologist has dedicated his career to studying Mexican glaciers, and says that measures should have been taken much earlier to prevent Ayoloco’s fate. The disappearance of this key water source cannot be reversed, and soon ice-free slopes and stones scattered like bones are all that will be left of Mexico’s once plentiful glaciers.

Delgado came to Iztaccíhuatl in 1974 to learn to walk on snow. He climbed the magnificent Ayoloco glacier with a hammer and ice ax, and lived here for two weeks in 1979 to prepare an expedition to the Himalayas. He lost his best friend on that mission. He has crossed this mountain so many times that he does not know the exact figure, and knows it like the back of his hand. “Our ice is heroic,” he says. “It is resisting as long as it can”.

Iztaccíhuatl is Mexico’s third-highest peak at 5,230 meters. Back in 1958, 11 glaciers were counted here in a national survey. Now only three remain: the Pecho, the Panza and the Suroriental glaciers. Between them, they barely cover 0.2 square kilometers, but in 1850 they stretched over 6.23 square kilometers, during the tail-end of the so-called “Little Ice Age”. In 170 years, the mountain has lost 95% of its glacier mass.

Mexico’s last five glaciers have a grim prognosis. Delgado predicts that in the next five years the three on Iztaccíhuatl will have disappeared

In the rest of Mexico, only two other permanent masses of ice remain: “El Norte” (North) Glacier and the small “Noroeste” (Northwestern) Glacier, totalling little more than 0.6 square kilometers. They are found in the Pico de Orizaba, also known as Citlaltépetl, on the border of the Mexican states of Puebla and Veracruz. The Pico de Orizaba is the highest mountain in the country, at 5,675 meters, and the third-highest in North America. Four glaciers have disappeared from its slopes over the last sixty years. El Norte, the geologists’ last hope, has lost its “tongues” - ridges or protrusions that snaked up the mountain. “The rock is showing through,” explains Delgado, “the ice layer is minimal”.




Remnants of the masses of ice that still survive in Iztaccíhuatl. On the video, the ascent to the former glacier of Ayoloco (Spanish language).PHOTO | VIDEO: TERESA DE MIGUEL


Mexico’s last five glaciers have a grim prognosis. Delgado predicts that in the next five years the three on Iztaccíhuatl will have disappeared. He gives those on Pico de Orizaba two decades. In any case, he says: “In 2050 there will be no glaciers in Mexico”.

Delgado also represents his country in the international glacier research group, and for years he has endured the jokes of Latin American colleagues, proud of the magnificent glaciers of Ecuador or Peru. “‘Soon you won’t even need to show up,’” they used to say, laughing at me... They have gone from making fun of the size of my glaciers to worrying about their own as they watch the ice vanish,” he explains.

The continuing disappearance of glaciers is a mirror held up to the world we are heading for: warmer, drier, worn out.

This fast-accelerating extinction is happening to ice masses simultaneously around the world. From Ok in Iceland to Pizol in Austria, the funerals are happening in quick succession, with requiems for Spanish glaciers and new lakes forming in the Himalayas. No one, no matter where they are, can escape global warming. Glaciers are a sensor for climate change: the more the planet’s temperature rises, the faster they retreat. Their continuing disappearance is a mirror held up to the world we are heading for: warmer, drier, worn out.

You can hear crunching footsteps on the earth, the heavy breathing and the bristling zacatones, plants that cover the slopes of Iztaccíhuatl like a blanket. In a clearing, before reaching the snow, crosses commemorate Luis Rosas, a mountaineer who died in 1971, and Daniel Peralta, who lost his life in 2013. These plaques in homage to mountain lovers inspired the farewell to Ayoloco.

The silence on the path suddenly shifts to a low, constant rumble. “Can you hear that? It’s a gas leak, with a lot of pressure. There are sometimes some explosions. It’s Popocatépetl,” says Robin Campion, a volcanologist from UNAM who accompanies Delgado on his expeditions to the glaciers. From the foothills of Iztaccíhuatl, the smoke of the other volcano is clearly outlined in the clear May sky, as a constant reminder of its presence.

Popocatépetl also had glaciers until 2000, when a strong eruption buried them. “There is still some ice left, but it does not function as a glacier because it has no movement or feeding process. In fact, those ice masses are ironically being preserved by the volcano’s ashes,” explains Delgado. If one day Popocatépetl falls dormant and the temperature increase has not melted the ice, the glacier could be regenerated.

A thick blanket of clouds accompanies the mountaineers on their ascent until it covers their feet, knees and the belly of Iztaccíhuatl. The hollow that occupied the Atzintli glacier until around 2012 appears on the western slope, on the route to Ayoloco. Now lizards hide among the rock piles and lichen at 4,500 meters above sea level. For centuries both glaciers were an important source of water during the dry season. Their names in Nahuatl, “heart of water” and “my water”, spell out the link with the people who lived here.

The two glaciers disappeared when the temperature increased and remained below the so-called “equilibrium line”. Geologists define this as the area in the mountains where the average annual temperature is zero degrees or less. Above this line, snow, blizzards or hail accumulate and feed the glacier. “As it feeds, it moves downslope due to gravity. When it exceeds the equilibrium line, it reaches what we call the ablation zone,” Delgado explains. This is where the temperature is higher than zero degrees and where everything begins to melt. “Glaciers have this dynamic of feeding and loss and there is a balance that allows them to conserve mass or lose it,” he adds.

This line of equilibrium has moved naturally over time. All the mountains of the Valley of Mexico taller than 3,500 meters were once covered with ice: the Ajusco, the Sierra de la Cruces, the Nevado de Toluca or the mountains of the Sierra Nevada all harbored glaciers. The temperature increase means that the level of the line is ever higher up. In 1958, it could be found in Mexico at 4,500 meters; now it is at 5,250 meters.

In addition to global warming, Mexican glaciers are trying to survive while surrounded by the industrial zones of the Valley of Mexico and Puebla state, and densely populated areas like Mexico City and Nezahualcoyotl

All of Iztaccíhuatl’s glaciers are already below the equilibrium line. “This means that solid precipitation has no hope of staying put,” Delgado explains. While the researchers secure the Ayoloco plate, the snow is falling heavily on the belly of the mountain. The rainy season has just begun and at this altitude the storm is shedding snowflakes relentlessly, but they do not cover all of the exposed rock. “The snow doesn’t last more than a few days, maybe a few weeks with luck. But it doesn’t stick, it can’t feed the glaciers.” The trio that remain on Iztaccíhuatl remain couched inside the craters, as the hollow protects the body of ice. “They are being maintained by the conditions on the surface, but the hope that they will stay is practically nil.”

Things are different at Pico de Orizaba. The summit and its glaciers are still 120 meters above the equilibrium line. But geologists have detected a lack of synchronization when it snows in the rainy season, which in Mexico coincides with summer. The high temperatures prevent the snow from sticking, and when it gets cold enough, there is no precipitation. “If things continue with the same temperature records, in a couple of decades they will disappear,” Delgado predicts.

In addition to global warming, Mexican glaciers are trying to survive while surrounded by the industrial zones of the Valley of Mexico and Puebla state, and densely populated areas like Mexico City and Nezahualcoyotl. As the glacial ice melts, outcrops of dark mountain rock start to appear which absorb instead of reflect solar radiation, causing additional warming.

A monitoring station on the Pico de Orizaba also corroborates that Mexico’s ice is “hot ice”, with a temperature so close to zero degrees that the ice melts easily with just a small rise in temperature. In addition, in the dry seasons the glaciers suffer from the sun’s rays due to their altitude and orientation, and although temperatures are low the ice turns from a solid state into gas and evaporates.

The loss of the Mexican glaciers means losing a sensor for climate change, but it also means losing a water source. In an increasingly populated and drier country – the average temperature in Mexico has risen 2ºC in the last 34 years – glaciers are an additional contribution to drinking water in the dry season for communities living near the mountains. They contribute about 5% of the region’s water, in runoff or by feeding into aquifers. “It’s very little, but even that will still cease to exist,” Delgado notes. All the signs – receding glaciers, melting poles, emptying dams – point in the same direction: “There will no longer be as much water available. Our society will be under water stress. It is a problem that is already here, but  the magnitude of it is not yet clear. The real challenge now is how we are going to adapt.”

There is no hope for these frozen masses fading slowly away on Mexico’s mountain tops, but we can try to slow down the process. Reducing greenhouse gases, saving water, avoiding deforestation and investing in environmental education are all necessary today. Delgado, who finds hope in the upcoming generation, concludes: “This is not to protect the planet, but the environment that allows us to survive as a species. We are risking our own existence.”

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