Seminar by Adrien Gilbert, Institute of Environmental Geosciences/IGE, Grenoble, France.
Sensitivity of Alpine glaciers to anthropogenic atmospheric forcings
Abstract: European Alpine glaciers have strongly shrunk over the last 150 years in response to climate warming. Glacier retreat is expected to persist and even intensify in future projections. This work aims at evaluating how much of the glacier retreat can be attributed to anthropogenic atmospheric forcings. For this purpose, we quantify the evolution of the Argentière glacier in the Mont Blanc area under different climate reconstructions over the period 1850-present. The different reconstructions are extracted from 4 ensemble experiments conducted with the IPSL-CM6-LR General Circulation Model (GCM), excluding and including natural and anthropogenic atmospheric forcings. These 6-member experiments are statistically corrected and downscaled with a quantile mapping approach that ensures consistent long term tendencies and precipitation-temperature relationship. These data feed a three-dimensional ice flow model coupled with a surface mass balance model to simulate changes in the glacier geometry over time. Over 1850-2014, experiment forced by the historical climate reconstruction show a good agreement with the observed glacier evolution and a mean volume loss of 32%. The natural-only experiment lead to a volume loss of about 10% revealing the great impact of anthropogenic forcings. The glacier also appears to be highly sensitive to individual anthropogenic forcings, with a glacier volume loss around 45% in the greenhouse gases-only experiment and a growth of about 5% in the aerosols-only experiment in 2014 relative to 1850. Our experiments also confirms that the end of the Little Ice Age would have occurred even without human activities. Finally, the simulations highlight a strong influence of natural internal variability and show that Argentiere Glacier definitively left its possible natural pathway only during the last decade.
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About the seminar
This seminar is offered by the Section for Geography and Hydrology, Dept. of Geosciences, University of Oslo. The GEOHYD-seminars are announced as lunch seminars so bring your lunch if you want to.
The seminars are open for everyone interested, and especially students are welcome.
The Lunch Seminar Team
– Louise and Sigrid