May 3, 2012

Sierra Nevada del Cocuy Glacier Retreat, Colombia

Posted by Mauri Pelto

The Sierra Nevada del Cocuy is the second largest concentration of glaciers in Colombia. The glaciated area in Colombia is at 6º27′ N and 72º18′ W and extends along the crest of this range. Morris et al (2006) documented the decline in total area from 39.1 square kilometers to 16.3 square kilometers in 2003. Poveda and Pineda (2009) estimated glacier area of as 28.6 km2 in 1989, 22.9 km2in 2000, and 17.00 km2 in 2007. A 40% decline in area in two decades. This post examines Landsat images from 1988 and 2012 and a Geoeye image from 2010. In the first image from 1988 identifies key local geographic localities, Laguna Grande de la Sierra (LGS), Laguna Grande de la Plaza (LGP), Concavo (C) Pulipito del Diablo (PD). The purple arrow indicates the separation of the main ice mass on PD from the arm extending north in 2010 (middle) and 2012 (bottom). The yellow arrow indicates the retreat of the glacier descending from Concavo toward LGS, from 1988 to 2012 the retreat has been 300 meters from 1988 to 2012. The glacier has declined from 1500 meters to 1200 meters in length. The red arrows indicate the separation of the Concavo glaciated summit and the arm of the glacier that extended to the north. What we see is the separation of a continuous ice mass along the crest of the Sierra del Concuy. Poveda and Pineda (2009) ask whether the glaciers will disappear during the 2010-2020 decade. Glaciers disappear because they lack a consistent and persistent accumulation zone (Pelto, 2010), we cannot just extrapolate onn glacier area decline. In this case the losses indicate continued segmentation and separation, but clearly there are several key areas that have substantial area and will not disappear within the decade. There is insufficient data to identify if any of the glacier retain sufficient snowcover to be sustained with current climate.