Submarine melt as a potential trigger of the North East Greenland Ice Stream margin retreat during Marine Isotope Stage 3

Abstract

The Northeast Greenland Ice Stream (NEGIS) has been suffering a significant ice mass loss during the last decades. This is partly due to increasing oceanic temperatures in the subpolar North Atlantic, which enhance submarine basal melting and mass discharge. This demonstrates the high sensitivity of this region to oceanic changes. In addition, a recent study suggested that the NEGIS grounding line was 20-40 km behind its present-day location for 15 ka during Marine Isotope Stage (MIS) 3. This is in contrast with Greenland temperature records indicating cold atmospheric conditions at that time, expected to favour ice-sheet expansion. To explain this anomalous retreat a combination of atmospheric and external forcings has been invoked. Yet, as the ocean is found to be a primary driver of the ongoing retreat of the NEGIS glaciers, the effect of past oceanic changes in their paleo evolution cannot be ruled out and should be explored in detail. Here we investigate the sensitivity of the NEGIS to the oceanic forcing during the last glacial period using a three-dimensional hybrid ice-sheet-shelf model. We find that a sufficiently high oceanic forcing could account for a NEGIS ice-margin retreat of several tens of kilometres, potentially explaining the recently proposed NEGIS groundingline retreat during Marine Isotope Stage 3.

Ocean Circulation and Variability Beneath Nioghalvfjerdsbræ (79 North Glacier) Ice Tongue

“…and suggest that ocean warming may have driven major retreat of the 79NG grounding line relative to its present position during the Last Glacial Period (specifically 41-26 ka Tabone et al, 2019). An extended observational timeseries over multiple seasonal cycles would significantly improve our ability to distinguish between the various drivers of variability discussed here.…”

“…Changes in ice tongue thickness affect the ice tongue's buttressing of NEGIS, which holds a 1.1 m sea level equivalent (Morlighem et al, 2014). New studies indicate that the ocean around northeast Greenland is likely to experience the most dramatic warming of any Greenland region through 2100 (Slater et al, 2019) Journal of Geophysical Research: Oceans 10.1029/2020JC016091 and suggest that ocean warming may have driven major retreat of the 79NG grounding line relative to its present position during the Last Glacial Period (specifically 41-26 ka Tabone et al, 2019). An extended observational timeseries over multiple seasonal cycles would significantly improve our ability to distinguish between the various drivers of variability discussed here.…”

Introduction to eco-efficient materials for reducing cooling needs in buildings and construction

“…According to Watts (2018) , in February of 2017 the temperatures in the Arctic remained 20°C above average for longer than a week, increasing the melting rate. As a consequence, the replacement of ice by water led to a higher absorption of solar radiation, making the oceans warmer and being responsible for basal ice melting ( Tabone et al, 2019 ) and also for a warmer atmosphere ( Ivanov et al, 2016 ). This constitutes a form of positive feedback that aggravates the aforementioned problem.…”

Carbon dioxide sequestration on mortars containing recycled aggregates

“…According to Watts (2018), in February of last year, the temperatures in the Arctic remained 20 C above the average for longer than a week having increased the melting rate. As a consequence, the replacement of ice by water will lead to a higher absorption of solar radiation that makes oceans warmer being responsible for basal ice melting (Tabone et al, 2019) and also for a warmer atmosphere (Ivanov et al, 2016). This constitutes a positive feedback that aggravates the problem.…”