June 26, 2007

Mont Blanc Glaciers Refuse to Shrink?

If you have an interest in global warming and its effect on mountain glaciers, you will be thrilled to know that there are over one million websites on the subject. Even before you get to the first site, you already know what you will find. Burning fossil fuels increases atmospheric concentrations of greenhouse gases, the Earth is warming, mountain glaciers are in full retreat all over the planet, delicate ecosystems are in peril, and humans who rely on the freshwater from mountain glaciers better get creative fast. Recall that in the Gore film, a great deal of attention was paid to the diminishing “snows of Kilimanjaro” – Gore has made hay in Glacier National Park as well pointing to shrinking glaciers. Retreating mountain glaciers have become a poster-child of the global warming alarmists – no presentation on the subject is complete without one.

The Intergovernmental Panel on Climate Change (IPCC) says in their recent 2007 Summary for Policymakers “Mountain glaciers and snow cover have declined on average in both hemispheres. Widespread decreases in glaciers and ice caps have contributed to sea level rise.” Someone in Europe missed the memo on this subject as a recent article has appeared in the Journal of Geophysical Research entitled “Very high-elevation Mont Blanc glaciated areas not affected by the 20th century climate change.” To say the least, we at World Climate Report were interested in what the authors had to say.

The research was conducted by six scientists from leading agencies and departments in France and Switzerland that deal with hydrology and glaciology. Before you see the title of the article and immediately suspect some conspiracy funded by European coal companies, be aware that the research was funded by Observatoire des Sciences de l’Univers de Grenoble (OSUG), the European Programs ALPCLIM and CARBOSOL, and by the city of Chamonix Mont-Blanc. Given the title of the article, we wonder if the six scientists will ever be funded again by any European agencies.

If your geography on the Mont Blanc region is a bit rusty, the map below will help (Figure 1). Mont Blanc is located on the border of Switzerland and France, and the summit of Mont Blanc is clearly visible from the United Nations complex in Geneva – the home of countless meetings of the IPCC and other international agencies addressing the climate change issue. How ironic – based on the title of the article, we doubt the research will be prominently featured in any upcoming IPCC meeting in Geneva?


Figure 1. The French Alps. ‘‘Mont Blanc’’ on the map shows the location of the Mont Blanc and Dôme du Goûter ice fields. The Chamonix, Bourg St. Maurice, and Besse en Oisans meteorological stations are also plotted (from Vincent et al., 2007).

The Vincent et al. team collected a variety of datasets that could help them understand how the high elevation glaciers of Mont Blanc were impacted by variations and trends in climate. Among other findings, they found that the mass balance of the glaciers is strongly controlled by precipitation, not temperature. The team used accurate survey maps from 1905 to compare to maps they generated with modern GPS measurements, and by subtracting the two surfaces, they could determine changes in the ice fields during the 20th century (see the two figures below).

Vincent et al. state “The most striking features of these figures are the small thickness changes observed over the 20th century. For both areas, thickness variations do not exceed ±15 m. The average changes are +2.6 m at Dôme du Goûter and -0.3 m at Mont Blanc. Considering the uncertainty interval, i.e., ±5 m, it can be concluded that no significant thickness change is detectable over most of these areas”. Putting all their findings together regarding the surface mass balance (SMB) of these two glaciers, they state “All these results suggest that the SMB at Dôme du Goûter and Mont Blanc did not experience any significant changes over the 20th century.” The first sentence of their conclusions section states “Geodetic measurements carried out in 1905 and 2005 on the highest ice fields of the Mont Blanc range indicate small thickness changes and show that these very high-elevation glaciated areas have not been significantly affected by climate change over the last 100 years.” Later in the conclusions section, they write “In any case, this study reveals that the very high-elevation ice fields in the Mont Blanc area have not been affected by the climate warming. The 20th century climate warming affected the atmospheric temperature in the Alps by +1°C. However this change did not significantly affect the ice deformation rate in the high-altitude ice fields since the ice temperature remains far below the melting point and therefore keeping the glacier frozen to its bed.”

We get the message, but we strongly suspect folks at the United Nations in Geneva would have no time for this message from the top of nearby Mont Blanc!

Figure 2. Thickness changes (m) at Dôme du Goûter between 1905 and 2005, from an old map and recent geodetic measurements (from Vincent et al., 2007).

Figure 3. Thickness changes (m) on the Mont Blanc ice cap between 1905 and 2005 (from Vincent et al., 2007).

Reference:

Vincent, C., E. Le Meur, D. Six, M. Funk, M. Hoelzle, and S. Preunkert (2007), Very high-elevation Mont Blanc glaciated areas not affected by the 20th century climate change, Journal of Geophysical Research, 112, D09120, doi:10.1029/2006JD007407.




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