Changes in the Geometry and Volume of Rabots glaciär, Sweden, 2003-2011: Recent accelerated volume loss linked to more negative summer balances

Terminus geometry, ice margins, and surface elevations on Rabots glaciär were measured using differential GPS during summer 2011 and compared with those similarly measured in 2003. Glacier length over the eight years decreased by ∼105m corresponding to 13ma^-1, a rate consistent with ice recession over the last several decades. Measured changes in surface elevations show that between 2003 and 2011 the glacier's volume decreased by ∼27.6±2.6×10⁶m³, or 3.5±0.3×10⁶m³a^-1. This compares favorably with an estimate of -28.1±2.6×10⁶m³ based on a mass-balance approach. The rate of volume loss appears, however, to have significantly increased after 2003, being substantially greater than rates determined for the intervals 1959-80, 1980-89, and 1989-2003. This increase corresponds to a sustained interval of more negative summer balances. Previous work suggests that as of 2003 Rabots glaciär had not yet completed its response to a ∼1°C warming that occurred c. 1900, and thus the current marked increase rate of ice loss might reflect the effect of recent, or accelerated regional warming that occurred during the last decade superimposed on its continued response to that earlier warming.