Recent changes (1991–2010) in glacier mass balance and air temperature in the European Alps

Abstract

AbstractWe estimate temperature sensitivity of observed mass balance for glaciers in the European Alps to compare with our earlier estimates from modelling. We treat 1961-90 as our reference period and compare mass balance for 1991-2010 with this reference period. There are eight Alpine glaciers with long enough records. The mean mass balance for the eight glaciers is close to zero for the reference period, very negative for 1991-2010 and highly negative in the exceptionally warm year 2003. Mass-balance changes are compared with 1991-2010 temperature anomalies to give an average temperature sensitivity of approximately -0.7 ± 0.2 m w.e. a-1 K-1 for the eight glaciers. There is considerable variation between individual glaciers, with higher sensitivity for western glaciers and lower sensitivity for eastern glaciers. Temperature sensitivity for the eight glaciers is strongly correlated with the standard deviation of observed mass balance, which from earlier work is known to be correlated with winter balance. The mean temperature sensitivity for observed mass balance is in reasonable agreement with values from earlier models, but changes in glacier hypsometry during 1991-2010 may have further increased observed mass loss.