L. G. Thompson et al., PNAS 2009, Glacier loss on Kilimanjaro continues unabated

Proceedings of the National Academy of Sciences, published online before print November 2, 2009; doi: 10.1073/pnas.0906029106

Glacier loss on Kilimanjaro continues unabated

L. G. Thompson*, H. H. Brecher, E. Mosley-Thompson, D. R. Hardy and B. G. Mark


Edited by James E. Hansen, Goddard Institute for Space Studies, New York, NY, and approved September 22, 2009 (received for review June 1, 2009) 

Abstract

The dramatic loss of Kilimanjaro's ice cover has attracted global attention. The three remaining ice fields on the plateau and the slopes are both shrinking laterally and rapidly thinning. Summit ice cover (areal extent) decreased ≈1% per year from 1912 to 1953 and ≈2.5% per year from 1989 to 2007. Of the ice cover present in 1912, 85% has disappeared and 26% of that present in 2000 is now gone. From 2000 to 2007 thinning (surface lowering) at the summits of the Northern and Southern Ice Fields was ≈1.9 and ≈5.1 m, respectively, which based on ice thicknesses at the summit drill sites in 2000 represents a thinning of ≈3.6% and ≈24%, respectively. Furtwängler Glacier thinned ≈50% at the drill site between 2000 and 2009. Ice volume changes (2000–2007) calculated for two ice fields reveal that nearly equivalent ice volumes are now being lost to thinning and lateral shrinking. The relative importance of different climatological drivers remains an area of active inquiry, yet several points bear consideration. Kilimanjaro's ice loss is contemporaneous with widespread glacier retreat in mid to low latitudes. The Northern Ice Field has persisted at least 11,700 years and survived a widespread drought ≈4,200 years ago that lasted ≈300 years. We present additional evidence that the combination of processes driving the current shrinking and thinning of Kilimanjaro's ice fields is unique within an 11,700-year perspective. If current climatological conditions are sustained, the ice fields atop Kilimanjaro and on its flanks will likely disappear within several decades.

*Correspondence:  thompson.3@osu.edu

Link to free, full, open-access article:  http://www.pnas.org/content/early/2009/10/30/0906029106.full.pdf+html

Link to abstract:  http://www.pnas.org/content/early/2009/10/30/0906029106.abstract