Atmosphere-driven ice sheet mass loss paced by topography: Insights from modelling the south-western Scandinavian Ice Sheet
Peer reviewed, Journal article
MetadataVis full innførsel
Marine-terminating glaciers and ice streams are important controls of ice sheet mass balance. However, understanding of their long-term response to external forcing is limited by relatively short observational records of present-day glaciers and sparse geologic evidence for paleo-glaciers. Here we use a high-resolution ice sheet model with an accurate representation of grounding line dynamics to study the deglaciation of the marine-based south-western Norwegian sector of the Scandinavian Ice Sheet and its sensitivity to ocean and atmosphere forcing. We find that the regional response to a uniform climate change is highly dependent on the local bedrock topography, consistent with ice sheet reconstructions. Our simulations suggest that ocean warming is able to trigger initial retreat in several fjords, but is not sufficient to explain retreat everywhere. Widespread retreat requires additional ice thinning driven by surface melt. Once retreat is triggered, the underlying bedrock topography and fjord width control the rate and extent of retreat, while multi-millennial changes over the course of deglaciation are modulated by surface melt. We suggest that fjord geometry, ice-ocean interactions and grounding line dynamics are vital controls of decadal-to centennial scale ice sheet mass loss. However, we postulate that atmospheric changes are the most important drivers of widespread ice sheet demise, and will likely trump oceanic influence on future ice sheet mass loss and resulting sea level rise over centennial and longer time scales.
TidsskriftQuaternary Science Reviews
OpphavsrettCopyright 2018 The Author(s)
Viser innførsler beslektet ved tittel, forfatter og emneord.
Ice-sheet dynamics and glacial development of the Norwegian continental margin during the last 3 million years Ottesen, Dag (Doctoral thesis, 2007-06-29)This thesis is mainly about the dynamics of the palaeo-ice sheets that covered Scandinavia, Barents Sea and Svalbard during the last glaciation. Morphological interpretation of regional and detailed bathymetric data sets ...
Ice sheets, oceanic circulation & sea surface conditions: the NW European margin during the last 35,000 years Becker, Lukas (Doctoral thesis, 2018-04-20)The north-western European continental margin provides a key area for detailed investigations of changes within the inflow of Atlantic warm surface currents, fluctuations in continental ice sheets and the corresponding ...
Irvali, Nil; Galaasen, Eirik Vinje; Ninnemann, Ulysses S; Rosenthal, Yair; Born, Andreas; Kleiven, Helga Flesche (Peer reviewed; Journal article, 2020-01-07)The Greenland Ice Sheet (GIS) has been losing mass at an accelerating rate over the recent decades. Models suggest a possible temperature threshold between 0.8 and 3.2 °C, beyond which GIS decline becomes irreversible. The ...