There is a new paper
Huss, M., M. Funk, and A. Ohmura (2009), Strong Alpine glacier melt in the 1940s due to enhanced solar radiation, Geophys. Res. Lett., 36, L23501, doi:10.1029/2009GL040789
with the abstract
“A 94-year time series of annual glacier melt at four high elevation sites in the European Alps is used to investigate the effect of global dimming and brightening of solar radiation on glacier mass balance. Snow and ice melt was stronger in the 1940s than in recent years, in spite of significantly higher air temperatures in the present decade. An inner Alpine radiation record shows that in the 1940s global shortwave radiation over the summer months was 8% above the long-term average and significantly higher than today, favoring rapid glacier mass loss. Dimming of solar radiation from the 1950s until the 1980s is in line with reduced melt rates and advancing glaciers.”
Excerpts from the paper read
“The drivers for these long-term variations cannot be detected based on the available data sets as they do not resolve all components of the energy balance. ……We therefore caution against using classical temperature-index models calibrated in the past for projecting snow and ice melt in glaciological and hydrological studies and to calculate future sea level rise.
“Our data sets provide evidence that the extraordinary melt rates in the 1940s can be attributed to enhanced solar radiation in summertime. Models for past and future glacier changes should take into account the effect of decadal radiation variations as they significantly alter the relationship between glacier melt and air temperature.”
This is yet another study that documents the inability to properly describe the climate system when it is oversimplified by focusing on just the metric of surface air temperature anomalies. The higher Alpine glacier melt in the 1940s, also provides evidence that this climate event is not primarily caused by a long-term trend in the global warming (or cooling).