TY  - JOUR
A1  - Levermann, Anders
A1  - Feldmann, Johannes
T1  - Scaling of instability timescales of Antarctic outlet glaciers based on one-dimensional similitude analysis
JF  - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union
N2  - Recent observations and ice-dynamic modeling suggest that a marine ice-sheet instability (MISI) might have been triggered in West Antarctica. The corresponding outlet glaciers, Pine Island Glacier (PIG) and Thwaites Glacier (TG), showed significant retreat during at least the last 2 decades. While other regions in Antarctica have the topographic predisposition for the same kind of instability, it is so far unclear how fast these instabilities would unfold if they were initiated. Here we employ the concept of similitude to estimate the characteristic timescales of several potentially MISI-prone outlet glaciers around the Antarctic coast. Our results suggest that TG and PIG have the fastest response time of all investigated outlets, with TG responding about 1.25 to 2 times as fast as PIG, while other outlets around Antarctica would be up to 10 times slower if destabilized. These results have to be viewed in light of the strong assumptions made in their derivation. These include the absence of ice-shelf buttressing, the one-dimensionality of the approach and the uncertainty of the available data. We argue however that the current topographic situation and the physical conditions of the MISI-prone outlet glaciers carry the information of their respective timescale and that this information can be partially extracted through a similitude analysis.
Y1  - 2019
U6  - https://doi.org/10.5194/tc-13-1621-2019
SN  - 1994-0416
SN  - 1994-0424
VL  - 13
IS  - 6
SP  - 1621
EP  - 1633
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Feldmann, Johannes
A1  - Levermann, Anders
A1  - Mengel, Matthias
T1  - Stabilizing the West Antarctic Ice Sheet by surface mass deposition
JF  - Science Advances
N2  - There is evidence that a self-sustaining ice discharge from the West Antarctic Ice Sheet (WAIS) has started, potentially leading to its disintegration. The associated sea level rise of more than 3m would pose a serious challenge to highly populated areas including metropolises such as Calcutta, Shanghai, New York City, and Tokyo. Here, we show that the WAIS may be stabilized through mass deposition in coastal regions around Pine Island and Thwaites glaciers. In our numerical simulations, a minimum of 7400 Gt of additional snowfall stabilizes the flow if applied over a short period of 10 years onto the region (-2 mm year(-1) sea level equivalent). Mass deposition at a lower rate increases the intervention time and the required total amount of snow. We find that the precise conditions of such an operation are crucial, and potential benefits need to be weighed against environmental hazards, future risks, and enormous technical challenges.
Y1  - 2019
U6  - https://doi.org/10.1126/sciadv.aaw4132
SN  - 2375-2548
VL  - 5
IS  - 7
PB  - American Assoc. for the Advancement of Science
CY  - Washington
ER  -