In the Northern Hemisphere, ~1500 glaciers, accounting for 28% of glacierized area outside the Greenland Ice Sheet, terminate in the ocean. Glacier mass loss at their ice-ocean interface, known as frontal ablation, has not yet been comprehensively quantified. Here, we estimate decadal frontal ablation from measurements of ice discharge and terminus position change from 2000 to 2020. We bias-correct and cross-validate estimates and uncertainties using independent sources. Frontal ablation of marine-terminating glaciers contributed an average of 44.47 ± 6.23 Gt a−1 of ice to the ocean from 2000 to 2010, and 51.98 ± 4.62 Gt a−1 from 2010 to 2020. Ice discharge from 2000 to 2020 was equivalent to 2.10 ± 0.22 mm of sea-level rise and comprised approximately 79% of frontal ablation, with the remainder from terminus retreat. Near-coastal areas most impacted include Austfonna, Svalbard, and central Severnaya Zemlya, the Russian Arctic, and a few Alaskan fjords.

View related articles View Crossmark data Citing articles: 1 View citing articles Iceberg production and characteristics around the Prince of Wales Icefield,

Over the last two decades, Trinity, Wykeham, Ekblaw, and Cadogan glaciers have retreated and been identified as the primary sources of iceberg flux from Prince of Wales (POW) Icefield, Ellesmere Island, accounting for ∼83% of total solid ice discharge. In this study, we used a total of 167 Radarsat‐2 Synthetic Aperture Radar scene pairs collected between 2009 and 2019 to derive winter surface velocities of these four major basins of the POW Icefield. Over this period both Cadogan and Ekblaw glaciers underwent multiyear acceleration and deceleration limited to their lower parts, consistent with characteristics of “pulse‐type” glaciers. Trinity and Wykeham glaciers are currently the fastest flowing glaciers in the CAA and are grounded below sea level for ∼40 km up‐glacier from their termini. Both glaciers underwent multiyear repeating periods of velocity acceleration between 2009 and 2019 which coincided with significant thinning at their termini. As of 2017, Trinity and Wykeham were each within ∼10 m of flotation over their lowermost 4 km. We also identified a shift in flow since 2014 on Trinity and Wykeham, after which winter flow rates began to propagate up‐glacier and were nearly identical to flow rates observed throughout the rest of the year, indicating that seasonal variability in flow has become less apparent in recent years. Our findings suggest that Trinity and Wykeham glaciers have transitioned to a flow type dominated by dynamic thinning, which is strongly influenced by subglacial topography and may be susceptible to instability of the glacier front and large‐scale collapse.

No abstract