The mid-point of these requisite climatic conditions for any glacier is called the equilibrium line. Above the line, the glacier accumulates more ice than is lost through melting; below the line, the opposite is true. As Jamapa\u2019s equilibrium line continues to rise, there will be changes that force a reconsideration of whether or not it is still technically a glacier. That is according to Guillermo Ontiveros, the study\u2019s lead researcher. \u201cWhen do we say that a glacier ceases to exist? There is still no consensus,\u201d he tells Dialogue Earth.<\/p>\n\n\n\n
What does seem inevitable, according to Ontiveros, is that Jamapa will fragment into two ice bodies, one high and one low. That division could happen at any moment, and \u201ccould already be interpreted as the death of the glacier\u201d.<\/p>\n\n\n\n
Over his lifetime, \u00c1lvarez has seen all but one of the 14 glaciers<\/a> that once existed on this mountain disappear. That morning, the sounds beneath the ice felt like another farewell.<\/p>\n\n\n\n \u201cPerhaps we will become extinct together.\u201d<\/p>\n\n\n\n During that same mid-2025 ascent, \u00c1lvarez noticed something he had never experienced since his first climb of Pico de Orizaba in December 1968, when he was only 13. He felt \u201cwarm rain\u201d falling on the glacier. It left the ice washed and shiny, exposed directly to the sun\u2019s rays.<\/p>\n\n\n\n A 2024 study<\/a> documenting the glacier\u2019s accelerated retreat says its surface area was 0.46 sq km in 2019. By 2024, it had shrunk to 0.37 sq km, and the crevasse under the ice at its edges had deepened. Importantly, the air temperature at the bottom of the ice body and within its accumulation zone had also risen steadily, the study notes.<\/p>\n\n\n\n As he descended, \u00c1lvarez followed the path of the meltwater. The weather behaved \u201clike never before\u201d, he says. There were blizzards and sudden changes. At 5,000 m, it began to rain, with lightning, in a place where it once only snowed.<\/p>\n\n\n\n Experts say this is a sign that the zero isotherm \u2013 the invisible line above which precipitation usually falls as snow \u2013 has shifted upwards. \u201cFifty years ago, it didn\u2019t rain at 4,000 m. Now it rains up to 5,600 m,\u201d says \u00c1lvarez.<\/p>\n\n\n\n Downpours like the one he experienced change everything: they cause landslides, erode the mountain and alter its morphology. They leave behind moraines \u2013 marks on rocks that reveal the presence of glaciers that have since disappeared.<\/p>\n\n\n\n Rain, once rare at these heights, is part of the glacier\u2019s final climate. Meanwhile, its meltwater flows along an underground river towards the Gulf of Mexico.<\/p>\n\n\n\n Once it leaves the mountain, the Jamapa enters forests of Mexican mountain pine (Pinus hartwegii<\/em>). According to two local sources who did not want to be identified over safety concerns, illegal logging and timber trafficking groups operate here. Some of these groups even stop those who climb the volcano and charge a \u201cright of way\u201d fee.<\/p>\n\n\n\n Mountaineers and expedition members who spend the night in the Piedra Grande lodge, located on the north side of the volcano at an altitude of 4,200 m, hear vehicles passing along clandestine trails all night. One expert with decades of experience in the area, who also did not want to be named, says there are at least 30 such routes in the 20,000 hectares that make up the Pico de Orizaba National Park\u2019s protected area. Logs are transported through here to cities in the two states that divide the mountain, Puebla and Veracruz.<\/p>\n\n\n\n Further down, the river reaches settlements in the municipality of La Perla, such as Vaquer\u00eda and Nuevo Jacal. According to official data<\/a> recorded in 2020, more than 55% of La Perla\u2019s population live in extreme poverty and almost 40% live in moderate poverty.<\/p>\n\n\n\n The Pico de Orizaba National Park\u2019s director Armando Fuentes tells Dialogue Earth there are 24 water committees in the area, made up of residents participating in reforestation and land care. He acknowledges that illegal logging remains a serious problem. The park\u2019s former director, Luis \u00c1lvarez, says many farming families make ends meet by facilitating passage of this timber.<\/p>\n\n\n\n Mexico\u2019s National Forestry Commission (Conafor) has established<\/a> forest loss as a factor that directly contributes to global heating: the carbon that would have been absorbed by felled trees becomes atmospheric. This heating melts glaciers.<\/p>\n\n\n\n However, Mexico\u2019s environment ministry (Semarnat) says deforestation is the national park\u2019s biggest problem, and that it is being compounded by the water running down the slopes and elevated sections of the mountain, causing severe impacts for the flora, fauna and soil. Landslides, Semarnat says, are the expression of the direct relationship between glacier melt and damage to the surrounding forest. <\/p>\n\n\n\n One of these landslides formed during Hilario \u00c1lvarez\u2019s descent. A loud crackling from the earth announced the fall of rocks, stones, mud and water.\u00a0<\/p>\n\n\n\n After its course has run more than 300 km, beyond the mountain forests, Jamapa\u2019s meltwater joins the Cotaxtla, one of four great rivers that originate in the Pico de Orizaba National Park. It then flows through regions of fruit crops, sugar cane and extensive livestock farming. \u201cFor more than 500 years, there has been a very strong link between human communities and this river,\u201d Jordi Vera, a researcher specialising in water consumption in the region, tells Dialogue Earth.<\/p>\n\n\n\n On its way to the sea, the river supplies water to more than half a million people across at least 34 municipalities<\/a>. It also passes by large industrial operations that extract groundwater, explains Vera.<\/p>\n\n\n\n The researcher predicts that the lower basin areas \u201cwill have to adapt\u201d to the river\u2019s new state, that of a seasonal flow that is dependent on the rain. \u201cPeople are already very concerned, because it is their most immediate source and they will no longer have water by gravity,\u201d Vera continues. \u201cThey will have to pump it from nearby streams. Other strategies are being discussed, such as adjusting consumption and reusing water.\u201d<\/p>\n\n\n\n This is reinforced<\/a> in Announcement of an approching death, which states that the glacier\u2019s extinction \u201cwill affect the availability of water supply\u201d in the Jamapa River Basin.<\/p>\n\n\n\n Finally, the Jamapa flows into the Gulf of Mexico at the edge of its coral reef system. The linear distance between Citlalt\u00e9petl and this point is 110 km, but the stream of water that began as meltwater to become a torrent of sediment, nutrients and energy, feeding coral reefs and sustaining rich marine biodiversity, has been on a winding 368 km journey.<\/p>\n\n\n\n As Leonardo Ortiz, a biologist at the University of Veracruz, tells Dialogue Earth: \u201cThe glacier and the reefs have been connected for about 10,000 years.\u201d In 2019, Ortiz led a team that discovered 23 new reefs<\/a> on the central coast of Veracruz.<\/p>\n\n\n\n This team also participated in a citizen lawsuit<\/a> that reached Mexico\u2019s supreme court. Its historic ruling in February 2022 ordered a halt to the expansion of the port of Veracruz, due to its environmental impact. The case set key precedents and is considered \u201ca turning point\u201d for environmental law in Mexico according to the lawyer who led the 10-year litigation, Xavier Mart\u00ednez. He describes to Dialogue Earth how, for the first time, the court used the \u201cprinciple of prevention\u201d and \u201crevoked all permits and ordered a holistic and comprehensive evaluation\u201d. The mega-project was deemed environmentally damaging, therefore infringing the human right to a healthy environment.<\/p>\n\n\n\n Today, these reefs are facing the disappearance of Jamapa, which will reduce the river\u2019s nutrient supply. \u201cIt\u2019s as if we were using the state of the reef and the state of the glacier as indicators of how the system is functioning,\u201d says Ortiz. \u201cIt\u2019s a symptom that tells you: this is happening in the glacier. But if it\u2019s happening in the glacier, it’s happening even more intensely everywhere else.\u201d<\/p>\n\n\n\n![\"man](\"https:\/\/dialogue.earth\/content\/uploads\/2026\/03\/Hilario-Aguilar_mountaineer_Jamapa-Glacier_Mexico_Rodrigo-Soberanes.jpg\")
<\/div>Signs of climate change<\/h2>\n\n\n\n
![\"melting](\"https:\/\/dialogue.earth\/content\/uploads\/2026\/03\/melting_Jamapa-Glacier_Mexico_Rodrigo-Soberanes.jpg\")
<\/div>Human impact<\/h2>\n\n\n\n
![\"Pine](\"https:\/\/dialogue.earth\/content\/uploads\/2026\/03\/pine-forest_Pico-de-Orizaba_Mexico_Leonardo-Diaz-Romero_Alamy-3BKBT12.jpg\")
<\/div>Signs from the sea<\/h2>\n\n\n\n
For more than 500 years, there has been a very strong link between human communities and the Jamapa river<\/blockquote>Jordi Vera, a researcher specialising in water consumption in the region<\/cite><\/div><\/div>\n\n\n\n