Andean Glacier Bird - Diuca speculifera

Environmental change at Quelccaya Ice Cap - image gallery

Our paleoclimate research at Quelccaya is providing perspectives on environmental change over multiple timescales. In collaboration with Lonnie Thompson at Ohio State University for example, ice cores (see paleoclimate section of images) are providing annual-resolution records going back ~1,500 years. Other aspects are documenting change over the long-term (e.g., millennia), and the short-term (e.g., annual). This section of images provides a glimpse into these results.

The Quelccaya Ice Cap is currently retreating from a much larger extent during the Little Ice Age (i.e., 19th century), leaving behind an extensive recessional moraine complex. By impounding runoff, these moraines maintain extensive areas of wetlands where plant and bird life flourishes. Wetlands were apparently present well before the Little Ice Age, however, for as the ice margin retreats, in situ soft-bodied plant material is being exposed in favorable sites. Thompson has collected samples which 14C date to 5,138 (±45) years ago. (“Alpaca moss” Distichia muscoides is the species; details of discovery here.) This finding clearly shows that when these plants were growing, the ice cap margin was at a higher elevation than today. Was Diuca-finch nesting on the glacier at that time?

At 5,100 years ago the regional temperature was probably warmer than today. Quelccaya Ice Cap then began expanding as the climate cooled and/or became wetter. Today, the margin is thinning, and at a higher elevation than at any time in the past 5,000 years. This plant evidence, and that from the ice cores (paper), together indicates that today’s temperatures are higher than at any time in the past 5 millennia. Likewise the elevation of glacier-nesting sites.

Changes in runoff from the glacier are driving shorter-term environmental changes underway around Quelccaya, where water is often a limiting factor for plant growth during the dry season. Recent local-scale changes provide an analog for what is likely to occur on a continental scale within decades: Between the 2006 and 2007 field seasons, a new sub-glacier pathway for runoff developed in the area near our Moraine Camp. As a result, streamflow was cut off from an area which had abundant year-around water for perhaps millennia (see images). Although this change was probably due to thinning of the glacier, the impact was localized; the same volume of runoff was simply diverted into another valley. However, the Quelccaya margin continues to thin and retreat to higher elevations, perhaps at an accelerating pace. In the near future, as warming continues, the volume of runoff from this – and most other Andean glaciers – will begin to diminish in response to decreasing ice volume. This will seriously impact natural and human systems, both locally and throughout South America (paper).   BACK

Last updated: 30 October 2008
Doug Hardy, UMass Geosciences