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Lima, Peru Top Impact Other Impacts
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Peru and other countries in Latin America generate a large portion of their electricity from hydropower, which lights up the Palacio de Justicia in Peru's capital city, Lima. Yet glaciers in the tropical Andes have been shrinking, including Peru's Qori Kalis glacier; and as glaciers disappear, water supplies for hydropower are likely to be threatened over the long run.1 |
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Key Facts As the Andes glaciers shrink (due at least in part to rising temperatures), supplies of drinking water and water for electricity generation may be at serious risk over time.4,2 Lima, Peru, is the world's second-largest capital city located in a desert, and as its population increases, electricity demand is expected to rise.
Details Andean glaciers are receding.7,8 Between 1932 and 1994, 10 glaciers in Peru retreated between 1,936 feet (590 meters) and 6,266 feet (1910 m).9 It is possible that many may vanish completely by mid-century if climatic trends continue as they have over the several decades leading up to 2010.6,10,11,,12,13 A glacier's mass is the net result of seasonal snow accumulation and seasonal ice loss. This can be affected by warming temperatures, but also by changes in snowfall, increases in solar radiation absorption due to a decrease in cloud cover, and increases in the water vapor content of air near the earth's surface.2,14,15,16,17 In Cordillera Blanca, Peru, for example, one study of glacier retreat between 1930 and 1950 linked the retreat to a decline in cloud cover and precipitation.18 Findings suggest glacier retreat in the Andes between 1950 and 1998 correlates to rising temperatures and humidity.2 Between 1950 and 1994 the tropical Andes warmed by an average of 0.3° F (0.15° C) per decade while the relative humidity in the southern Peruvian Andes increased between 0.5 and 1 percent per decade.2 This may not sound like much, but in a dry environment such as the high Andes, any increase in relative humidity can translate into a significant change for glaciers.19 Because it takes eight times as much energy to convert ice directly into water vapor (a process called sublimation) than it does to melt ice,2 higher relative humidity in this location tips the balance of glacial ice loss away from sublimation and toward melting. Some argue that the combined increase in temperature and humidity is the major reason for accelerated tropical glacier retreat in the Andes toward the latter half of the twentieth century.2 As temperatures increased, glacier retreat accelerated.5 The total area of Peru covered by glaciers dropped by around 22 percent over the last three decades of the twentieth century.20,7,21 The Quelccaya ice cap in the southern Peruvian Andes lost at least 20 percent of its surface area between 1963 and 2000,22 and its main tongue, the Qori Kalis glacier, shrunk by around 76.1 million cubic feet per year (2,155,000 cubic meters per year) between 1983 and 1991—more than a seven-fold increase over its average shrinkage rate of around 10.2 million cubic feet per year (290,000 cubic meters per year) between 1963 and 1978.10 Part of a Larger PatternTropical glaciers in Peru serve to control water supplies by producing runoff during drier periods, and accumulating ice during wetter periods.7 This important function is likely to be reduced and ultimately lost as glaciers retreat. The melting of glaciers in the Cordillera region, for example, could have serious ramifications for nearby Lima, Peru's capital city. Lima's 8 million residents rely on these glaciers both for water in the dry season and for the majority of their hydroelectric power. The Mantaro River—one of the rivers most likely to be affected by the shrinking glaciers—is home to a hydroelectric plant that supplies 40 percent of Peru's power and 70 percent of its industrial electricity.20 Across much of Latin America, hydroelectric plants are the main source of electricity.5 Around 82 percent of the electricity generated in Peru in 2002 came from hydropower.23 What the Future HoldsPeru's overall demand for electricity is projected to increase an average of 4 percent each year between 2002 and 2030.23 Continued glacier retreat could create critical conditions between 2015 and 2025, affecting water supplies needed for 60 percent of the population and for hydroelectricity generation.20,10,22 Natural gas may be used to meet increasing electricity demand in Peru, with one economic analysis projecting natural gas to account for around 50 percent of Peru's electricity by 2030 while hydroelectricity generation drops to about 43 percent.23 This increase in fossil fuel burning would also increase CO2 emissions, making matters worse by trapping more heat in the atmosphere. On the other hand, research suggests Peru has favorable conditions for the development of both wind and solar power generation.24 Even if energy demands are met, however, some studies warn that agricultural development may expand due to the temporary increase in water flow from rapidly shrinking glaciers—which may threaten even more livelihoods because those glaciers may eventually disappear.25,26 Endnotes
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Global Warming Effects Around the World
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