No general stability conditions for marine ice-sheet grounding lines in the presence of feedbacks

Using theoretical, numerical and data analyses, this study finds that there are no general stability conditions for marine ice sheets if feedbacks caused by interactions of ice sheets with atmosphere, ocean and lithosphere are taken into account. The marine ice-sheet instability hypothesis continues to be used to interpret the observed mass loss from the Antarctic and Greenland ice sheets. This hypothesis has been developed for conditions that do not account for feedbacks between ice sheets and environmental conditions. However, snow accumulation and the ice-sheet surface melting depend on the surface temperature, which is a strong function of elevation. Consequently, there is a feedback between precipitation, atmospheric surface temperature and ice-sheet surface elevation. Here, we investigate stability conditions of a marine-based ice sheet in the presence of such a feedback. Our results show that no general stability condition similar to one associated with the marine ice-sheet instability hypothesis can be determined. Stability of individual configurations can be established only on a case-by-case basis. These results apply to a wide range of feedbacks between marine ice sheets and atmosphere, ocean and lithosphere.

Automated summary

Using theoretical, numerical and data analyses, this study finds that there are no general stability conditions for marine ice sheets if feedbacks caused by interactions of ice sheets with atmosphere, ocean and lithosphere are taken into account. Stability of individual configurations can be established only on a case-by-case basis.