EGU22-13209, updated on 08 Dec 2023
https://doi.org/10.5194/egusphere-egu22-13209
EGU General Assembly 2022
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Attribution of extreme annual glacier mass loss to anthropogenic forcing

Lauren Vargo1, Ruzica Dadic1, Brian Anderson1, Regine Hock2,3, Huw Horgan1, Andrew King4,5, Andrew Mackintosh6, and Ben Marzeion7
Lauren Vargo et al.
  • 1Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
  • 2Department of Geosciences, University of Oslo, Oslo, Norway
  • 3Geophysical Institute, University of Alaska Fairbanks, Alaska, USA
  • 4School of Geography, Earth, and Atmospheric Sciences, University of Melbourne, Melbourne, Australia
  • 5ARC Centre of Excellence for Climate Extremes, University of Melbourne, Melbourne, Australia
  • 6School of Earth Atmosphere and Environment, Monash University, Melbourne, Australia
  • 7Institute of Geography and MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany

Glaciers in every region on Earth have lost mass over the past two decades as global temperature has risen 0.5C. Retreating glaciers symbolize climate change and present societal challenges across the globe. To better quantify the consequences of climate change, previous studies have established methods to calculate the anthropogenic component of extreme weather and climate events. Previously, we established a framework using existing event attribution methods together with glacier mass balance modeling to determine the increase in probability of extreme annual mass loss of New Zealand glaciers occurring with climate change. Here, we look to expand our developed attribution framework to calculate the change in probability and amount of extreme annual mass loss for glaciers around the world.

 
To do this, we simulate glacier mass balance using a degree-day model, driven with general circulation model (GCM) output from available CMIP6 models and ensemble members. Historical natural simulations define climate without anthropogenic forcing, and SSP5 8.5 simulations define climate with anthropogenic forcing. We use the two different climate forcings to produce scenarios of glacier mass change with and without climate change. The differences in these scenarios are compared with measurements from the highest annual glacier mass loss years.
 

We develop the attribution method though application to several glaciers around the world, including South Cascade Glacier (USA), Gries Glacier (Switzerland), and Brewster Glacier (New Zealand). Our initial results show large increases in probability and amount of annual glacier mass loss occurring due to climate change for all three glaciers. Difficulties in applying the attribution framework to glaciers globally include accessing modern glacier outlines and reconciling differences between glaciological and geodetic measurements of glacier mass change.

How to cite: Vargo, L., Dadic, R., Anderson, B., Hock, R., Horgan, H., King, A., Mackintosh, A., and Marzeion, B.: Attribution of extreme annual glacier mass loss to anthropogenic forcing, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-13209, https://doi.org/10.5194/egusphere-egu22-13209, 2022.