The progressive extinction of ice fields in the Andean region has generated unprecedented impacts on the contribution of water to countries that depend on their flows, including Chile, a country that ironically has the largest number of glaciers in South America.
Glaciers and ice-covered land surfaces represent about 10% of the Earth's surface and contain about 70% of the world's freshwater. The Andes encompass a wide range of topographic and climatic conditions, stretching from the coastal region of Venezuela (Venezuelan Andes) to Patagonia and Tierra del Fuego in Chile, with a length of approximately 7,000 km, making it the longest mountain range in the world (Figure 1). It hosts the largest glacierized| area in the Southern Hemisphere outside Antarctica. According to recent global estimates, Andeans glaciers are among the largest contributors to sea level rise (Dussaillant et al., 2019).
To understand in greater detail why glaciers are so important to our lives, it is necessary to consider three crucial reasons:
Indicators of Climate Change: Glaciers are sensitive to the climate around them, making them effective indicators of the imbalance in the Earth's climate system. Their changes in size and mass reflect broader climatic shifts.
Contributors to Sea Level Rise: Glaciers significantly contribute to global sea level rise. Their melting can cause minor impacts—just a few millimeters—to major changes—several meters—affecting coastlines worldwide.
Long-term Water Reserves: In arid regions, glaciers play a critical role in ensuring water supply to rivers during the dry summer months, helping to mitigate the negative impacts during drought periods.
Andean Glaciers
Indeed, although Andean glaciers are relatively small compared to the vast ice sheets, they play a crucial role in ensuring the water supply to South American rivers during the driest months of summer, helping to mitigate the negative impacts during periods of drought.
FEATURE | Andean Glacier | Greenland Glacier | Antarctic Glacier |
GEOGRAPHIC LOCATION | Andes mountain range in South America. | Greenland island in the North Atlantic. | Antarctic continent in the South Pole. |
WEATHER | Tropical, subtropical and arid, with seasonal variation. | Polar, extremely cold, low precipitation. | Polar, extremely low temperatures, low precipitation. |
SIZE | Relatively small, ranging from a few to several km2. | Second largest ice sheet in the world (1.7 million km2). | Largest ice sheet in the world (14 million km2). |
DYNAMICS | Comparatively more dynamic and highly sensitive to climate change. | More stable, but with significant recent melting. | More stable inland, melting in coastal areas. |
IMPACTS ON SEA LEVEL RISE (SLR) | Limited impact due to smaller ice volume. | Significant: melting could raise sea level by approx. 7 meters. | Greatest potential impact: could raise sea level by up to 58 meters if completely melted. |
ALTITUDE | High, generally above 3,000 meters. | Low, close to sea level. | Varied, mostly above sea level, with large ice sheets covering the continent. |
PRECIPITATION | Seasonal, varying with season and location. | Mostly snow, but scarce. | Scarce, mostly in the form of snow. |
Table 1: Comparison of Andean glaciers and the largest glaciers in the world. Source: Self-made, 2024
How do glaciers help counteract negative impacts?
Glaciers play a crucial role in counteracting negative environmental impacts in several ways:
When it comes to water storage and supply, glaciers store about 69% of the world's freshwater. During warmer months, melting glaciers release water, contributing to river flows and providing a consistent water supply for agriculture, drinking, and industrial use while releasing stored water during dry periods, helping to mitigate the effects of drought and ensuring a continuous water supply for ecosystems and human populations.
Regarding to climate regulation, glaciers and ice sheets reflect a significant portion of solar radiation back into the space due to their high reflectivity (albedo effect). This helps to regulate the Earth’s temperature and maintain a cooler climate.
Glacial meltwater supports cold-water ecosystems that can store carbon, such as certain types of algae and phytoplankton, which contribute to the global carbon cycle and help mitigate the effects of greenhouse gases.
Melting glaciers along the Andes
Glaciers will not always be able to deliver the same volume of water in the face of rising environmental temperatures. Initially, they will deliver more and more water until the glacier reaches a size where the contribution is maximized. Once this point is passed, its size will not be sufficient to sustain this contribution, leading to a sustained reduction until it finally reaches a new equilibrium or disappears. This concept is defined as 'peak flow', which is crucial for understanding and managing water resources in regions where glaciers play a fundamental role in water supply.
Many Andean glaciers represent significant water resources across extensive portions of the Tropical and Arid Andes, where glacier melting acts as a buffer during periods of drought.
Along with Central Asia, the Andes is a region where glacier melt contribution can reach 50% or more of the total flow in some basins, and where the greatest reductions in glacier runoff are projected by the end of the 21st century.
Since 2010, precipitation in central Chile has been below normal every year by an average of 20 to 45%. Around Santiago, home to over 7 million people, the lack of rain has been particularly extreme, with only 10 to 20% of normal rainfall (NASA, 2020) occurring in recent years, marking a 'megadrought,' corresponding to the longest and most extreme drought in Chile's modern meteorological record since 1915.
This weighs heavily on the Arid Andes, where most of the Chile's population resides, primarily in the capital city of Santiago. In this region of the Andes, the "unbalanced" contribution from the Maipo glacier basin has increased from one decade to the next, coinciding with an intense period of drought that has been affecting the Chilean population for over a decade.
In this image you can see how one of the main water reservoirs in Santiago has been receding from 2016 to 2020 in El Maipo. The Yeso Reservoir, which supplies the Metropolitan Region with fresh water, suffered an impressive decline, going from 219 to 99 million cubic meters in just four years, decreasing its capacity by 60%. (Earth Observatory, 2020).
Consequences of the melting of Andean Glaciers
The total glacier mass loss in The Andes of -22.9 ± 5.9 gigatonnes (Gt) during the period 2000-2018 corresponds to a sea-level rise (SLR) of 0.06 ± 0.02 mm per year. This represents a little over 10% of the global glacier contribution (0.55 mm per year) during 2002-2016. This value is 50% higher than the contribution to sea-level rise from all High Mountain Asia glaciers, even though the latter cover an area three times larger (Dussaillant et. al., (2019). To this significant glacier mass loss is added the decrease in rainfall that has affected Chile, particularly in the Arid Andes region. This combination of factors has left the country with major problems, especially for farmers.
In August 2019, the Ministry of Agriculture of Chile declared agricultural emergencies for more than 50 municipalities. Tens of thousands of farm animals have died, and many more are at risk. Water supply systems are strained, and reservoirs are low. In many rural areas, people depend on deliveries of potable water via tanker trucks, and the situation seems to worsen over time.
This water crisis has become the most impactful issue in Chile regarding climate change, surpassing even deforestation and biodiversity loss. Chile is home to around 24,000 glaciers, containing approximately 80% of South America's glaciers.
Adaptation in Chile and the world
Chile has implemented various strategies to adapt to the megadrought that has affected the country since 2010:
Water Management
Water Management Plans: Implementation of regional and national plans for efficient water management.
Storage Infrastructure: Construction and improvement of reservoirs and dams to store water during wet seasons.
Irrigation Technologies: Promotion of more efficient irrigation technologies, such as drip irrigation, to reduce water wastage in agriculture.
Seawater Desalination
Desalination Plants: Construction of desalination plants in coastal regions to provide potable water to cities and industrial sectors.
Wastewater Reuse
Treatment and Reuse: Promotion of treated wastewater treatment and reuse for agricultural and industrial purposes.
Education and Awareness
Farmer Training: Training programs for farmers in efficient irrigation techniques and sustainable water management.
Research and Monitoring
Scientific Research: Funding for research on climate change and water management to develop data-driven solutions.
Water Resources Monitoring: Advanced water resources monitoring systems for better decision-making.
What about the other countries?
Other countries affected by prolonged droughts have adopted various adaptation strategies. Australia has implemented the Murray-Darling Basin Plan to manage water resources and has built desalination and wastewater reuse plants. Israel has developed advanced drip irrigation technologies and has constructed numerous desalination plants, in addition to treating wastewater for agricultural use. Spain manages its river basins comprehensively and promotes the use of treated wastewater for irrigation and industrial purposes. In California, United States, water use restrictions are imposed, incentives are offered for water-saving devices, and wastewater reuse programs are developed. These strategies reflect the diversity of approaches taken by different countries to address the challenges of water scarcity and drought.
References
Australian Government Department of Agriculture, Water and the Environment. (n.d.). Murray-Darling Basin Plan. Retrieved from https://www.awe.gov.au/water/policy/mdb.
California Department of Water Resources. (n.d.). Water Conservation and Drought. Retrieved from https://water.ca.gov/Water-Basics/Conservation-and-Drought.
Dussaillant, I., Berthier, E., Brun, F. et al. Two decades of glacier mass loss along the Andes. Nat. Geosci. 12, 802–808 (2019). https://doi.org/10.1038/s41561-019-0432-5.
Gassert, F., Landis, M., Luck, M., Reig, P., & Shiao, T. (2014). Aqueduct Global Maps 2.1. Washington, DC: World Resources Institute. Retrieved from https://datasets.wri.org/dataset/aqueduct-global-maps-21-data.
Intergovernmental Panel on Climate Change. (2018). Global warming of 1.5°C: An IPCC special report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty (V. Masson-Delmotte, P. Zhai, H.-O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, & T. Waterfield, Eds.). Retrieved from https://www.ipcc.ch/sr15/
Israel Water Authority. (n.d.). Water Management. Retrieved from http://www.water.gov.il/Hebrew/WaterManagement/Pages/default.aspx.
Ministerio para la Transición Ecológica y el Reto Demográfico. (n.d.). Planificación hidrológica. Retrieved from https://www.miteco.gob.es/es/agua/temas/planificacion-hidrologica/.
NASA Earth Observatory. (2020). A strained water system in Chile. NASA. https://earthobservatory.nasa.gov/images/146577/a-strained-water-system-in-chile.
Sección A.3 del Resumen para Tomadores de Decisiones del ‘Reporte especial de Océanos y Criósfera en un Clima Cambiante, SROCCC”, publicado por el IPCC.
U.S. Geological Survey. (n.d.). What is a glacier? U.S. Department of the Interior. Retrieved June 4, 2024, from https://www.usgs.gov/faqs/what-glacier.
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