The near-global retreat of glaciers over the last century provides some of the most iconic imagery for communicating the reality of anthropogenic climate change to the public. Surprisingly, however, there has not been a quantitative foundation for attributing the retreats to climate change, except in the global aggregate. This gap, between public perception and scientific basis, is due to uncertainties in numerical modelling and the short length of glacier mass-balance records. Here we present a method for assessing individual glacier change based on the signal-to-noise ratio, a robust metric that is insensitive to uncertainties in glacier dynamics. Using only meteorological and glacier observations, and the characteristic decadal response time of glaciers, we demonstrate that observed retreats of individual glaciers represent some of the highest signal-to-noise ratios of climate change yet documented. Therefore, in many places, the centennial-scale retreat of the local glaciers does indeed constitute categorical evidence of climate change.
The Earth Surface Dynamics seminar series aims to bring together the broad range of researchers on Telegrafenberg looking at Earth surface processes, e.g., hydrology, earth surface geochemistry, geobiology, geochemical/carbon cycling, geomorphology, etc. once a month. The goal for these talks is to be broad and accessible and deal with big, global topics, so that non-experts and specialists alike can find them enlightening.