17 Feb 2022
17 Feb 2022
Status: a revised version of this preprint is currently under review for the journal TC.

Ongoing grounding line retreat and fracturation initiated at the Petermann Glacier ice shelf, Greenland after 2016

Romain Millan1,2, Jeremie Mouginot2,3, Anna Derkacheva1, Eric Rignot3,4, Pietro Milillo5, Enrico Ciraci4, Luigi Dini6, and Anders Bjørk2 Romain Millan et al.
  • 1Université Grenoble Alpes, CNRS, IRD, INP, 38400, Grenoble, Isère, France
  • 2Department of Geosciences and Natural Resources Management, University of Copenhagen, 1350, Copenhagen, Denmark
  • 3Department of Earth System Science, University of California, Irvine, 92697, CA, USA
  • 4Jet Propulsion Laboratory, Caltech, Pasadena, CA, USA
  • 5Department of Civil and Environmental Engineering, University of Houston, TX, USA
  • 6Italian Space Agency, Matera, Italy

Abstract. The Petermann ice shelf is one of the largest in Greenland, buttressing 4 % of the total ice sheet discharge, and is considered dynamically stable. In this study, we use differential synthetic aperture radar interferometry to reconstruct the grounding line migration between 1992 and 2021. Over the last thirty years, we find that the grounding line of Petermann retreated 4 km, 7.5 km and 4.5 km in the western, central and eastern sectors, respectively. However, it is only since 2017 that the glacier has undergone a significant retreat in its central section, receding more than 5 km along a retrograde bed grounded 500 m below sea level. Simultaneously, two large fractures developed, splitting the ice shelf in three sections, with partially decoupled flow regime. The retreat followed the warming of the ocean waters by 0.4 °C in Nares Strait. As a result, the glacier sped up by 15 % in 2016–2018. While the central sector stabilized on a sill, the eastern flank is sitting on top of a down-slopping bed, which might accentuate the glacier retreat in the coming years.

Romain Millan et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on tc-2022-16', Anonymous Referee #1, 25 Feb 2022
    • AC1: 'Reply on RC1', Romain Millan, 21 Apr 2022
  • RC2: 'Comment on tc-2022-16', Anonymous Referee #2, 18 Mar 2022
    • AC2: 'Reply on RC2', Romain Millan, 21 Apr 2022

Romain Millan et al.

Romain Millan et al.


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Short summary
We detect for the first time a dramatic retreat of the grounding line of Petermann glacier, a major glacier of the Greenland Ice Sheet. This was followed by a speed up of the glacier and a fracturation of the ice shelf. This sequence of events is also coherent with ocean warming in this region and suggests that Petermann has initiated a phase of destabilization, which is of prime importance for the stability and future contribution of the Greenland ice sheet to sea level rise.