In terms of changes in surface area and length, the glacier retreat in the tropical Andes over the last three decades is unprecedented since the maximum extension of the Little Ice Age (LIA, mid-17th–early 18th century). This is a serious concern because a large proportion of the population lives in arid regions to the west of the Andes. In terms of changes in mass balance, the trend has been quite negative over the past 50 years.
Even if glaciers are currently retreating everywhere in the tropical Andes, it should be noted that this is much more pronounced on small glaciers at low altitudes that do not have a permanent accumulation zone, and which could disappear in the coming years/decades. Monthly mass balance measurements performed in Bolivia, Ecuador and Colombia show that variability of the surface temperature of the Pacific Ocean is the main factor governing variability of the mass balance at the decadal timescale.
Temperature increased at a significant rate of 0.10°C/decade in the last 70 years. The higher frequency of El Niño events and changes in its spatial and temporal occurrence since the late 1970s together with a warming troposphere over the tropical Andes may explain much of the recent dramatic shrinkage of glaciers in this part of the world.
Andean glaciers melting at “unprecedented” rates: study
Reuters
Reporting by Mitra Taj; Editing by Sandra Maler.
Climate change has shrunk Andean glaciers between 30 and 50 percent since the 1970s and could melt many of them away altogether in coming years, according to a study published on Tuesday in the journal The Cryosphere.
Andean glaciers, a vital source of fresh water for tens of millions of South Americans, are retreating at their fastest rates in more than 300 years, according to the most comprehensive review of Andean ice loss so far.
The study included data on about half of all Andean glaciers in South America, and blamed the ice loss on an average temperature spike of 0.7 degree Celsius (1.26 degrees Fahrenheit) over the past 70 years.
“Glacier retreat in the tropical Andes over the last three decades is unprecedented,” said Antoine Rabatel, the lead author of the study and a scientist with the Laboratory for Glaciology and Environmental Geophysics in Grenoble, France.
The researchers also warned that future warming could totally wipe out the smaller glaciers found at lower altitudes that store and release fresh water for downstream communities.
“This is a serious concern because a large proportion of the population lives in arid regions to the west of the Andes,” said Rabatel.
The Chacaltaya glacier in the Bolivian Andes, once a ski resort, has already disappeared completely, according to some scientists.
Current state of glaciers in the tropical Andes: a multi-century perspective on glacier evolution and climate change
by A. Rabatel, B. Francou, A. Soruco, J. Gomez, B. Caceres, J. L. Ceballos, R. Basantes, M. Vuille, J.-E. Sicart, C. Huggel, M. Scheel, Y. Lejeune, Y. Arnaud, M. Collet, T. Condom, G. Consoli, V. Favier, V. Jomelli, R. Galarraga, P. Ginot, L. Maisincho, J. Mendoza, M. Menegoz, E. Ramirez, P. Ribstein, W. Suarez1, M. Villacis, and P.Wagnon
http://www-lgge.obs.ujf-grenoble.fr/personnels/rabatel_antoine/Publi/Rabatel2013TC.pdf
Andean glaciers ‘could disappear’: World Bank
http://phys.org/news154187547.html
Andean glaciers and the region’s permanently snow-covered peaks could disappear in 20 years if no measures are taken to tackle climate change, the World Bank warned.