Impacts
Gruber, S., M. Hoelzle and W. Haeberli. 2004. Permafrost thaw and
destabilization of Alpine rock walls in the hot summer of 2003. GRL 31,
L13504, doi: 10.1029/2004GL020051, 2004. Gruber et al. consider whether the
unusual summer of 2003 in Europe is an indicator of things to come under
climate change. The summer of 2003 was ~3°C warmer in Switzerland than the
1961-90 average and this coincided with exceptional rock fall activity,
especially at high elevations and on north-facing slopes. In the absence of
unusual precipitation or other possible effects on slope stability, the
authors hypothesize that rapid degradation of mountain permafrost is the
likely cause. They investigated this hypothesis using observations of air
and near surface temperature in steep rock faces in an energy balance model
to simulate summer thaw for the period 1982-2002 and compared it to 2003
rates. The modelled thaw of 2003 exceeded the maximum of the previous 21
years. , Authors conclude that these findings are cause for concern with
respect to future warming, suggesting that the locations, magnitudes and
frequencies of rock wall instabilities are likely to expand beyond the
ranges of historic variability. This instability has implications for
infrastructure, tourism and public safety in alpine ranges.
Better buy a new helmet...