To mark the United Nations' International Year of Glacier Conservation, we take a look at the surprising connection between glaciers and rainforests—and why melting glaciers in tropical regions have far-reaching consequences for the environment, biodiversity, and people.
Tropical Glaciers: Ice Giants at the Equator
Glaciers in the tropics? At first glance, this seems like a contradiction. But they do exist – hidden in the highest peaks on Earth, where temperatures remain icy despite the proximity to the equator. At least for now. Today, over 99% of these glaciers are located in the South American Andes, 71% of them in Peru alone. But isolated remnants of these once mighty ice giants can also be found in Africa, Asia, and Oceania. Unlike their counterparts in Patagonia, Scandinavia, or Siberia, which exist at altitudes of just a few thousand meters, tropical glaciers cling to extreme heights of over 4,000 meters – the last bastion against the heat of the tropics.
Nevertheless, these relics from the Ice Age are now more threatened than ever before. According to the latest studies, the decline of these glaciers has reached an unprecedented record: they have shrunk to their smallest size in at least 11,000 years – since the beginning of the Holocene, a warm period associated with the rise of human civilizations. Many could disappear completely in just a few decades. The “Eternity Glacier” in Indonesia is expected to melt away by 2026, and the glaciers of the Ruwenzori Mountains in Uganda are also on the verge of disappearing for good.
Due to their remote location or lack of tourist popularity, they often remain unnoticed. For many people, they are just fleeting white spots on the horizon – like lost clouds in the vast sky, disappearing into the flow of the landscape. Although many are unaware of it, these glaciers are more closely linked to other ecosystems than one might think. The Andes in particular demonstrate the close connection between tropical rainforests and glaciers – two seemingly opposite worlds that are nevertheless dependent on each other.
The fragile network: When glaciers melt
"Un elefante se balanceaba „One elefant was balancing
sobre la tela de una araña, on a spider’s web,
como veía que resistía, seeing that it held,
fue a llamar a otro elefante." he went to call another elefant.“
This is a popular children's song in Spanish in which an elephant balances on a spider's web. With each new verse, another elephant joins in, putting more strain on the web. The song teaches counting in a playful way, but the image of the unbreakable spider's web is an illusion. No web is strong enough to bear the weight of more elephants—eventually, every thread breaks.
Like the spider web, which loses strength with every additional load, our glaciers are increasingly at risk. In view of rising temperatures and the inexorable changes caused by climate change, it is becoming increasingly difficult for them to maintain their stability. What once functioned as a reliable water reservoir is becoming increasingly unstable and fragile – a process that is taking on dramatic proportions, especially in the tropics.
It is only a matter of time before the net breaks. Humanity has a responsibility to stop climate change, or at least to mitigate it. The vanishing of tropical glaciers threatens to disrupt the ecological balance, which could destroy the foundations of numerous ecosystems that depend on this fragile equilibrium. However, it is not only nature that is in danger – the stories, identities, and spiritual traditions of many cultures are also at risk of crumbling.
For many indigenous communities, glaciers are much more than just frozen water. They are sacred entities, living spirits, and ancient guardians of the earth. In the Andes, for example, they are revered as “Apus” – powerful mountain spirits who watch over the balance of nature. The retreat of these glaciers is therefore not only an ecological loss, but also a spiritual rupture, a sign that the harmony between humans and nature is faltering.
Tropical glaciers play an important role in the culture of indigenous peoples. © Elmer Ayala
The essential role of tropical glaciers for ecosystems and climate
Glaciers are vital water reservoirs and contribute to the stability of entire ecosystems. The meltwater that glaciers continuously release feeds rivers and is an indispensable source of drinking water, agricultural irrigation, and energy production. Especially during dry seasons, when other water sources are scarce, they secure the water supply of many regions and strengthen their ability to adapt to climatic challenges such as droughts.
However, their influence extends far beyond their immediate surroundings. Tropical glaciers flow into rivers that supply water to various ecosystems – from high mountain valleys and cloud forests to rainforests and even desert regions. In South America, for example, many of these glacial rivers flow into the Amazon, contributing to the stability of one of the most biodiverse ecosystems on Earth.
From a global perspective, glaciers are an essential pillar of the climate system. Their white surfaces reflect solar radiation and thus act as the Earth's natural air conditioning system, a phenomenon known as the albedo effect. However, the melting of glaciers also entails the loss of this natural cooling system. Less reflected sunlight leads to greater warming of the Earth, further accelerating the vicious cycle of global warming.
Furthermore, glaciers create unique habitats for specialized plant and animal species, such as lichens, mosses, and microorganisms, which are adapted to the extreme conditions. These special ecosystems are also on the brink of collapse, as rising temperatures threaten the subsistence of many of these species.
Decline of tropical glaciers – More than a natural disaster
The rapid melting of tropical glaciers has far-reaching consequences for the environment and for the societies that depend on these vital water sources. Even though their contribution to global sea level rise is relatively small, glacier retreat is significantly altering the ecological balance, hydrology, and landscape not only locally but also regionally.
Local effects
Locally, the loss of glaciers leads to unstable rock formations, which significantly increases the risk of landslides and mudslides. Glacial lakes, which are formed by the retreat of ice masses, are particularly dangerous. These lakes, often surrounded by unstable moraine walls, can break suddenly due to rapid melting processes or vibrations and cause devastating floods.
Another direct effect of glacier retreat is the drying up of the landscapes surrounding the glaciers. In high mountains and grasslands, the decline in meltwater leads to a reduction in soil moisture, which significantly affects vegetation. This change has a direct impact on grazing land, which is crucial for the subsistence economy of the local population. The reduced availability of grazing land makes livestock farming more difficult and thus jeopardizes the livelihoods of many families.
Regional impacts
The retreat of tropical glaciers also affects entire regions. Especially in the coastal region of Peru and northern Chile, which is characterized by deserts and arid zones, meltwater plays an indispensable role in agriculture and drinking water supply. During the dry season, entire valleys and cities such as Lima, with a population of around 10 million, depend on this water source.
In addition, tropical glaciers in the Andes play an important role as a source of energy for hydroelectric power plants that supply millions of people with electricity. The loss of these glaciers would undermine existing efforts to provide drinking water and clean energy for the most vulnerable populations and destroy the aspirations for social justice and equality. This development could exacerbate existing social crises, increase resentment, and elevate the risk of rural exodus and armed conflict.
Considering these challenges, adapting to alternative water sources and sustainable water management strategies is becoming a key task for the affected countries and the global community. The loss of tropical glaciers is therefore not only a natural disaster, but also a complex social challenge with far-reaching implications for the daily lives and future of entire regions.
Ice melt in the Andes: Many glaciers have receded considerably © Emilio Mateo/Aspen Global Change Institute/dpa
Tropical glaciers – a fragile interaction between climate, vegetation, and radiation
Glaciers are a symbol of the delicate balance of natural systems. Their survival depends on one crucial condition: annual snowfall must at least compensate for the loss of ice due to melting.
In temperate latitudes, winter usually compensates for summer melting through sufficient snowfall. In the tropics, however, this seasonal change is absent. Temperature patterns and precipitation during the rainy season determine the fate of glaciers. In some high mountain regions, considerable amounts of snow are deposited during the wetter months, but the high level of solar radiation throughout the year accelerates the melting process. This destabilizes the already delicate balance of the glaciers, a development that is further exacerbated by deforestation and climate change.
Clouds play a key role in this process: during the day, they reduce the intensity of solar radiation, slowing down ice loss. At night, they prevent heat from radiating unhindered into space, limiting cooling and freezing processes. In mountainous regions with frequent fog or dense cloud cover, moisture can also accumulate in the form of frost or freezing fog, adding extra mass to the glaciers. These interactions between precipitation, radiation, and cloud cover make tropical glaciers particularly vulnerable to climate change.
The delicate balance of glaciers is closely linked to the surrounding vegetation of tropical rainforests and cloud forests. Plants release large amounts of water vapor through transpiration, which contributes to local cloud formation. However, if the forest is cleared, there are fewer clouds. This leads to stronger solar radiation on the glaciers and accelerates their melting process.
Rising temperatures and changing wind patterns caused by climate change are amplifying these effects. Cloud formation and precipitation patterns are becoming increasingly disrupted, further worsening environmental conditions for glaciers. Extreme weather events such as the El Niño-Southern Oscillation (ENSO) are occurring more frequently and increasing fluctuations in precipitation and temperature. These processes are shifting the balance between accumulation and melting, causing tropical glaciers to lose mass at an ever-increasing rate.
Mutual influence: tropical glaciers and rainforests in South America
The tropical glaciers in the Andes are more closely linked to the Amazon rainforest than it might initially appear. The interaction between these two ecosystems influences not only the regional climate, but also the water cycle and biodiversity in South America.
The influence of the Amazon rainforest on the Andean glaciers
The Amazon rainforest plays a central role in the survival of the glaciers in the Andes. The glaciers depend on a constant supply of water, which comes mainly from precipitation in the Amazon basin, which in turn is fed by moist air from the Atlantic Ocean. This precipitation is caused by evapotranspiration in the rainforest, whereby plants release large amounts of water vapor into the atmosphere. The water vapor then forms clouds and precipitation, which ultimately supply the glaciers in the Andes.
But the Amazon rainforest is not only a source of water for glaciers, it is also a decisive factor in the local climate. The high moisture content of the air promotes the formation of clouds, which mitigate solar radiation and thus protect the glaciers from excessive warming. Without this natural “protective shield” of clouds, direct solar radiation would hit the glaciers more strongly, which would significantly accelerate their melting rates.
However, the loss of the rainforest has dramatic consequences for this sensitive system. The progressive deforestation reduces the amount of moisture released into the atmosphere, which decreases precipitation in the Andes. The lack of humidity also increases the likelihood of extreme weather events such as forest fires, which cause the glaciers to melt further. The smoke and soot particles produced by these fires settle on the glaciers, darkening their surface and causing them to absorb more heat—another factor that accelerates melting.
The latest scientific findings show that the Amazon has reached a tipping point. The rainforest, which once acted as a huge carbon sink, has begun to release carbon and has thus become a carbon emitter. This development is exacerbating global warming, which further aggravates the negative effects on the climate and glaciers. The loss of trees not only reduces rainfall, but also the rainforest's ability to mitigate climate change. The Amazon basin is drying up and transforming from a rainforest to a savanna in many areas.
This vicious circle has serious consequences: the glaciers are losing their water source and the rainforest is on the verge of collapse. The loss of biodiversity and climate change are already noticeable in the region today and could worsen if deforestation and climate change continue unabated.
A sea of green stretches across both land and water. Water lettuce (Pistia stratiotes) grows in a side stream and is used as food by endangered Amazonian manatees, among others. Photo taken in 2015 in the Pacaya-Samiria Reserve in Iquitos. © Mariel Ruiz-Gonzalez
The impact of Andean glaciers on South America's rainforests
The glaciers of the Andes are an essential part of the regional water cycle and play a key role in various ecosystems. Especially during dry periods in the absence of rain, they provide valuable meltwater to the highland rainforests of the Rupa Rupa – the forested eastern slopes of the Andes. When the glacial meltwater reaches the lower-lying regions, some of it evaporates and contributes to the formation of clouds. This dense cloud cover creates the typical fog in the montane rainforests and creates a humid microclimate that favors the diversity of epiphytes such as mosses, ferns, and orchids. As the glaciers retreat, temperatures rise and humidity falls, which in the long term dries out the rainforest and threatens the species living there.
The meltwater and the sediments, minerals, and organic matter it contains also contribute to plant growth and the stability of aquatic habitats in the rainforests. The nutrients improve soil fertility and maintain nutrient cycles in the aquatic ecosystems that extend far into the Amazon basin. A decline in this nutrient supply could not only reduce fish stocks in the long term but also disrupt the ecological balance and jeopardize the food security of many local communities.
The lush vegetation of the tropical mountain rainforests surrounds the Vilcanota River on both sides. Photo taken in 2015 on the way from Hydroelectrica to Aguas Calientes in Cuzco. © Mariel Ruiz-Gonzalez
Conclusion: The inseparable connection between tropical glaciers and rainforests
Protecting tropical rainforests and glaciers is crucial for the balance of global ecosystems. These two systems are closely intertwined, and the loss of one threatens the survival of the other.
The loss of tropical glaciers and rainforests implies the loss of natural resources that are essential for the well-being of many people and the ecological stability of our planet. Only through sustainable management and targeted protection measures can we preserve both systems for the survival of future generations.
Two young girls carry water in buckets. Although the village lies on the banks of the Nanay River, a side river of the Amazon, the region faces challenges in terms of drinking water supply. Photo taken in 2015 in Padre Cocha, a small village near Iquitos in the Peruvian Amazon. © Mariel Ruiz-Gonzalez
It's not too late – what you can do
The retreat of tropical glaciers and the threat to rainforests are serious challenges – but there is hope. Each of us can help protect this fragile balance. Even small changes in our everyday lives can make a difference: using resources more consciously and consuming sustainably helps to reduce our ecological footprint.
Stay informed and get involved! International initiatives such as World Glacier Day on March 21 or the International Year of Glacier Conservation offer opportunities to learn more about these urgent issues. Conferences such as the International Conference on Glacier Conservation 2025 allow the exchange of knowledge and solutions. You can also support NGOs that are committed to protecting rainforests and glaciers.
Political engagement is equally crucial: stay informed about campaigns and advocate for laws that prioritize environmental protection. Elections are an opportunity to help shape sustainable change.
Ultimately, real change often begins with dialogue. Talk to people from tropical countries about their experiences with rainforests and glaciers. What challenges do they face? What parallels are there with your own environment? The exchange of knowledge and perspectives leads to new solutions—and that is exactly what we need right now.
The future of our planet's tropical glaciers and rainforests is not yet sealed. It is up to us to take action and preserve this valuable heritage for future generations.
Author: Mariel Ruiz-Gonzalez, intern
Further resources and in-depth information
Videos
APU The weeping gods (Official Trailer), 2022. Chouette Films. https://www.youtube.com/watch?v=Hvgra2M_uUY, accessed on 14.03.2025.
Apus de Peru: Los misterios de las montañas sagradas (leyenda de los Andes), 2021. Voces del Nuevo Mundo. https://www.youtube.com/watch?v=ZiqqvkKxUE8, accessed on 14.03.2025.
APUS SAGRADOS DEL CUSCO, 2015. Ministerio de Cultura Cusco. https://www.youtube.com/watch?v=BYGl2ASmLYc, accessed on 14.03.2025.
Critically Endangered: The Last Tropical Glaciers. Dr Sevestre, Heïdi. 2019. https://www.youtube.com/watch?v=dxtqY-Wj7d8, accessed on 21.02.2025.
Crisis in the Amazon: Will the largest rainforest in the world survive?. BBC World Service, 2024. https://www.youtube.com/watch?v=8h7HGl4Xe1E, accessed on 16.03.2025.
High Altitude Glaciers in the Tropics. ThinkTV, 2010. https://www.pbslearningmedia.org/resource/ttv10.sci.ess.earthsys.tropical/high-altitude-glaciers-in-the-tropics/, accessed on 12.03.2025.
How the Amazon has started to heat the planet. It's Complicated. The Guardian. https://www.youtube.com/watch?v=CR5xL9WoVm8, accessed on 16.03.2025.
Peru & The Andes: Living on the Climate Change Frontlines. Die Vereinten Nationen, 2021. https://www.youtube.com/watch?v=EDh0VlEpluQ, accessed on 16.03.2025.
Peru is ‘on the brink of disaster as vital glaciers vanish. Sky News, 2021. https://www.youtube.com/watch?v=0EP7FBK5OZA, accessed on 06.03.2025
The Andean Glacier and Water Atlas: the impact of glacier retreat on water resources, 2018. UNESCO. https://www.youtube.com/watch?v=EjaQWFAIpFw, accessed on 16.03.2025.
The Tipping Points of Climate Change — and Where We Stand. Johan Rockström, TED, 2024. https://www.youtube.com/watch?v=Vl6VhCAeEfQ, accessed on 16.03.2025.
Tropical Glaciers Retreating Faster Than Ever! Greg K, 2024. https://www.youtube.com/watch?v=LkC0eRgCcEQ, accessed on 06.03.2025.
Literature
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Hansen, Kathryn. 2023. Quelccaya Ice Cap Then and Now. Nasa Earth Observatory. https://earthobservatory.nasa.gov/images/152124/quelccaya-ice-cap-then-and-now, accessed on 06.03.2025.
Ionescu, Andrei. 2022. Africa’s glaciers may disappear by 2040. Earth.com. https://www.earth.com/news/africas-glaciers-may-disappear-by-2040/, accessed on 21.02.2025.
Ionescu, Andrei. 2022. The world’s glaciers contain less ice than previously thought. Earth.com. https://www.earth.com/news/the-worlds-glaciers-contain-less-ice-than-previously-thought/, accessed on 21.02.2025.
Ionescu, Andrei. 2024. Tropical glaciers offer a glimpse of our harsh climate reality. Earth.com. https://www.earth.com/news/tropical-glaciers-offer-a-glimpse-of-our-harsh-climate-reality/, accessed on 21.02.2025.
Kimbrough, Liz. 2020. What starts in the Amazon doesn’t stay there: Fires melting Andes glaciers. Mongabay. https://news.mongabay.com/2020/01/what-starts-in-the-amazon-doesnt-stay-there-fires-melting-andes-glaciers/, accessed on 12.03.2025.
Peru’s Tropical Glaciers and Rainbow Mountains, Nasa Earth Observatory. https://earthobservatory.nasa.gov/images/151845/perus-tropical-glaciers-and-rainbow-mountains, accessed on 06.03.2025.
Ralls, Eric. 2016. Melting glaciers pose flood risk. Earth.com. https://www.earth.com/news/melting-glaciers-pose-flood-risk/, accessed on 21.02.2025.
Ratcliffe, Rebecca. 2023. Indonesia’s tropical Eternity Glaciers could vanish within years, experts say. The Guardian. https://www.theguardian.com/world/2023/aug/25/indonesia-tropical-glaciers-melting-el-nino, accessed on 21.02.2025.
Ribeiro, R. da R., Simões, J. C., & Ramirez, E. 2017. The Amazon Glaciers. InTech. https://www.intechopen.com/chapters/56963, accessed on 06.03.2025
Santora, Marc. 2021. A Warning That Africa’s Last Glaciers Will Soon Vanish. The New York Times. https://www.nytimes.com/2021/10/19/world/africa/mountain-glaciers-disappear.html, accessed on 06.03.2025.
Sexton, Chrissy. 2023. Ice cores from highest tropical peak reveal new climate clues. Earth.com. https://www.earth.com/news/ice-cores-from-highest-tropical-peak-reveal-new-climate-clues/, accessed on 06.03.2025.
Sexton, Chrissy. 2023. Peru has lost over half of its glaciers in six decades. Earth.com. https://www.earth.com/news/peru-has-lost-over-half-of-its-glaciers-in-six-decades/, accessed on 06.03.2025.
Sierra Praeli, Yvette. 2019. Perú: nevados y lagunas forman parte de la nueva Área de Conservación Regional Ausangate. Mongabay. https://es.mongabay.com/2019/12/peru-area-conservacion-regional-ausangate/, accessed on 21.02.2025.
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Wendle, John. 2023. For Uganda’s Vanishing Glaciers, Time Is Running Out. Yale Environment 360. Yale School of Environment. https://e360.yale.edu/features/rwenzoris-mount-stanley-africa-glaciers-climate-change, accessed on 21.02.2025.
Westbrook, Jesse. 2017. The effects of melting glaciers on tropical communities. Phys Org. https://phys.org/news/2017-01-effects-glaciers-tropical.amp, accessed on 06.03.2025.
Willige, Andrea. 2023. Explainer: What are tropical glaciers and why are they an indicator for climate change?. World Economic Forum. https://www.weforum.org/stories/2023/10/tropical-glacier-climate-change-elnino-indonesia/, accessed on 21.02.2025.