Melting ice sheets are the primary cause of sea level rise, which has accelerated over recent decades. In coastal areas, rising sea levels can increase the risk of flooding and endanger water sources – issues some communities are already facing. The potential impact of sea level rise on humanity is significant: about 40 percent of the world’s population lives within 100 kilometers of the coast and 8 of the world’s 10 largest cities are located in coastal areas.
But in the high Andes of Peru, glacial retreat poses a different and complex set of challenges related to water supply. These challenges have far-reaching implications for Peruvian society, from water quality and agriculture to development and the risk of catastrophic flooding.
The Peruvian Andes are home to 70 percent of the world’s tropical glaciers, many of which are concentrated in the “Cordillera Blanca” or “White Range”. Located in high mountain ranges around the equator, tropical glaciers are especially sensitive to climate change and, like other glaciers throughout the world, are retreating at an alarming pace. Peru’s glaciers have lost some 40 percent of their surface area since the 1970s.
During the dry season, glacial meltwater is an important water source for communities from the high Andes to the coast. In recent decades, the rapid melting of Peru’s glaciers has resulted in increased water flow across the region. This water boon has fueled large-scale agricultural production in arid lands and spurred development: new communities sprang up, hydroelectric plants began to supply power to thousands of consumers, and Peruvian blueberries and asparagus were exported to lucrative markets abroad.
Climate Change, Peru: Retreating Glacier
Felipe, an alpaca herder from the small Andean community of Pucarumi, explains how reduced water flow from the Ausungate glacier has impacted his life. “We are feeling the effects of climate change,” he says. “This loss of snow means we receive less water. This climatic factor is causing us great danger.”
But the abundance of water also brought complications. The water quality in rivers and streams declined as they became contaminated with heavy metals like lead and cadmium from newly exposed rocks and mining sites. These minerals also began to accumulate in croplands, impacting soil quality and agricultural productivity. Meltwater lakes at the foot of glaciers became swollen, threatening towns and cities with catastrophic flood events. An estimated 25,000 people have been killed by outburst floods and avalanches in the Santa River valley since the 1940s.
Front Variation: Pastoruri Glacier, Peru
The first internationally coordinated glacier monitoring program was initiated in 1894. During this early period, front variation – the changes in a glacier’s length or size over time – was glaciology’s primary scientific measurement. The front variation data for Peru’s Pastoruri Glacier shows that it has retreated by almost 500 meters (1,640 feet) since 1981. [Hover over chart for numbers | replay] Source: WGMS
Perhaps most worrisome is the likelihood that Peru’s glaciers, and the water they provide, will continue to decline in the years to come. A recent study found that seven out of nine watersheds in the Cordillera Blanca are already experiencing decreased water flow rates during the dry season. Once Peru’s glaciers are gone, annual streamflow may fall by as much as 30 percent in some watersheds. Conflicts over strained water resources may then reshape life in the Ancash region once again.
The Washington Post: A Flood of Problems