LONDON — The glaciers of the tropical Andes have shrunk by between 30 and 50 percent in 30 years and many will soon disappear altogether, cutting off the summer water supply for millions of people, according to scientists studying the region’s climate.
Their findings are particularly significant because glaciers in the tropics, 99 percent of which are in the Andes, are regarded as among the most sensitive indicators of climate change on the planet, according to the Intergovernmental Panel on Climate Change (IPCC).
The Pastoruri glacier, located in Northern Peru in the Andes.Credit: Wikimedia Commons
In the Andes glaciers contribute to irrigation, hydroelectricity generation, and water supply. For example, 15 percent of the water consumed in La Paz, the capital of Bolivia, comes from glaciers, a figure that doubles in the summer. The region, with 3.5 million people, is heavily dependent on melt water for its survival (and see our story of 25 January, Andean glaciers show record melting).
Many of the crops along hundreds of kilometers on the dry eastern slopes of the Andes rely on irrigation from glacier melt water in the summer.
The research covers 300 years of glacier history in South America. The glaciers reached their maximum extent during what is termed the Little Ice Age, between 1650 and 1730, when the world was colder. Rivers like the Thames in London and Seine in Paris froze over during some winters.
By studying rocky debris piled up during the Little Ice Age and then left behind as the glaciers retreated after 1750 the researchers have been able to chart their progress.
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