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The Andean Glaciers: From 12,000 Years Ago to Today

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Geological History

Although it may sound odd, the Earth is currently in an ice age, and has been for the last 2.58 million years. When we think of an ice age, we typically picture the entire planet covered in ice. In reality, scientists agree that our world goes through both glacial and interglacial periods during an ice age. The last interglacial period began 12,000 years ago, with the start of the Holocene epoch, and has continued to the present day. When the ice sheets began to retreat, humans were able to abandon their hunter-gatherer lifestyle to create permanent settlements and flourish into the civilization that we know today. Now, remnant glaciers are only found at the poles and on high mountains. The vast rivers of creaking, crushing ice remind us of the power of glaciers in shaping human history.

The Andes Mountain Range contains the world’s largest tropical glaciers, and its equatorial location also makes it particularly sensitive to changes in climate. In the past 10,000 years, the surface of the Andean glaciers has shrunk by more than 90 percent. [1] The majority of the melting has taken place in the past 200 years, since the Industrial Revolution. [2]

In the 1970s, scientists feared that the Earth would plunge back into another ice age. However, recent research has linked increased levels of atmospheric carbon dioxide with higher global temperatures, convincing the scientific community that the real danger is not a renewed ice age, but an increasingly warm world. Humans have lived through glacial periods in the past, but they have never lived in a world without any ice at all. During the previous 10,000 years, the amount of carbon dioxide in the atmosphere has fluctuated between about 180 and 280 parts per million. Today, it is at 390 parts per million.

Mountain ranges above 12,000 feet and the polar areas are expected to bear the brunt of climate change. In the last week of January, 2013, an alarming new study announced that the Andean glaciers have retreated 30 to 50 percent since the 1970s. [3] This has major implications for Bolivia, Colombia, Ecuador, and Peru, which all rely on glacial-fed rivers for water and hydropower.


Smaller Glaciers = Floods and Drought

As the Andean glaciers retreat, downstream villages and cities will experience new sources of flooding due to excess meltwater. Flash floods have been occurring for decades, but they are expected to increase in intensity and frequency in the upcoming years. When large chunks of ice fall into glacial lakes, they can displace a substantial amount of water, leading to flooding of nearby population centers. Communities already have been forced to take new measures against the threat. In 2010, citizens near the town of Carhuaz, Peru, were able to escape a flood precipitated by an ice avalanche because they had constructed tunnels to drain off extra water. [4] Warning systems and prevention measures have become a necessary investment for the protection of vulnerable populations.

After the periods of intense flooding, drought may become the new norm in the Andes region. Glacial water makes up a large percentage of river flow in several key locations. Peru’s Santa River, for example, now receives 30 percent of its flow from glacial runoff during the dry season. [5] Hundreds of thousands of Peruvians rely on the Santa River’s water for irrigation and drinking and will have to adjust to increased water shortages. La Paz, Bolivia is also a danger point for water shortages, as the city receives about 27 percent of its water from glaciers during the dry season. [6] There is little that can be done to increase the flow of glacial rivers, so the only option remaining for the Andean people will be a system of careful water conservation. Water recycling practices can be improved and reservoirs can be built to mitigate seasonal fluctuations, but overall, urban and rural areas will have to adjust to less water, inevitably impeding regional development.

Decreased river flow could be devastating for energy production in the Andean region, which at the present time is heavily reliant on hydroelectric power. As of now, Bolivia receives 31.7 percent of its electricity from water power, Colombia, 71.1 percent, Ecuador, 48.8 percent, and Peru, 55.8 percent. [7] While the rivers will not completely run dry and the dams will remain functional, energy production will experience a substantial drop. For example, a study of the Canon del Plata hydro-power system on the Santa River has determined that it would lose 37 percent of its power production capacity if the glaciers were to melt completely. [8] As a result, energy will be much harder to come by in the Andean region in the next few decades, driving up electricity prices.

Breaking the Feedback Loop

With less hydro-power , these countries may have to turn to fossil fuels for energy, which will create a feedback loop that increases the greenhouse effect that caused the melting of the glaciers in the first place. Plans for renewable energy in the Andes are in their infancy, as the region currently generates only 1 to 3 percent of its electricity from renewable sources.  Now is the ideal time to heavily invest in wind, solar, and other forms of clean energy. [9]

Unfortunately, the Andean countries do not have control over their own future in this regard. Climate change is a global problem, so even if Bolivia, Colombia, Ecuador, and Peru were to transform themselves into models of renewable energy production, they still would be affected by the carbon dioxide emissions of countries halfway around the world. Industrialized countries in North America and Europe, as well as developing countries with large populations such as India and China will have to shape their own policies to curb carbon emissions. The longer the world waits before confronting global climate change, the more the people downstream of the Andean glaciers will suffer the consequences.

Joel Jaeger, Research Fellow at the Council on Hemispheric Affairs

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[1] “10,000 Years of Andean Glacier Melt Explained.” Science Daily: Science News. September 9, 2011,

[2]“10,000 Years of Andean Glacier Melt Explained.” Science Daily: Science News. September 9, 2011,

[3] “Massive Melting of Andes Glaciers.” BBC News: Science and Environment. January 23, 2013,

[4]Ortega Arango, Santiago. “Andean Glacier Melt Threatens Floods, Then Drought.” AlertNet. January 3, 2013,

[5] Fraser, Barbara. “Melting in the Andes: Goodbye Glaciers.” News Feature. Nature. November 7, 2012,

[6] “Massive Melting of Andes Glaciers.” BBC News: Science and Environment. January 23, 2013,

[7]World Bank. 2013. Data retrieved February 10, 2013 from World Data Bank,

[8]Vergara, Walter, et al. Economic Impacts of Rapid Glacier Retreat in the Andes. Eos. 2008. 261-262

[9]World  Bank, 2013, Data retrieved February 10, 2013 from World Data Back