Read here. From the "science is never, ever settled department," new peer-reviewed research does in depth study on glaciers' retreat and find it's due to enhanced solar radiation.
"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."
