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In recent decades, Greenland's peripheral glaciers have experienced large‐scale mass loss, resulting in a substantial contribution to sea level rise. While their total area of Greenland ice cover is relatively small (4%), their mass loss is disproportionally large compared to the Greenland ice sheet. Satellite altimetry from Ice, Cloud, and land Elevation Satellite (ICESat) and ICESat‐2 shows that mass loss from Greenland's peripheral glaciers increased from 27.2 ± 6.2 Gt/yr (February 2003–October 2009) to 42.3 ± 6.2 Gt/yr (October 2018–December 2021). These relatively small glaciers now constitute 11 ± 2% of Greenland's ice loss and contribute to global sea level rise. In the period October 2018–December 2021, mass loss increased by a factor of four for peripheral glaciers in North Greenland. While peripheral glacier mass loss is widespread, we also observe a complex regional pattern where increases in precipitation at high altitudes have partially counteracted increases in melt at low altitude. Plain Language Summary: The Arctic is warming more rapidly than the rest of the world. This warming has had an especially profound impact on Greenland's ice cover. Only 4% of Greenland's ice cover are small peripheral glaciers that are distinct from the ice sheet proper. Despite comprising this relatively small area, these small peripheral glaciers are responsible for 11% of the ice loss associated with Greenland's recent sea level rise contribution. Using the satellite laser platforms Ice, Cloud, and land Elevation Satellite (ICESat) and ICESat‐2, we estimate that ice loss from these Greenland glaciers increased from 27 ± 6 Gt/yr (2003–2009) to 42 ± 6 Gt/yr (2018–2021). We find that the largest acceleration in ice loss is in North Greenland, where we observe ice loss to increase by a factor of four between 2003 and 2021. In some areas, it appears that recent increases in snowfall at high altitudes have partially counteracted recent increases in melt at low altitudes. While many recent Greenland ice loss assessments have focused on only the ice sheet, the recent sharp increase in ice loss from small peripheral glaciers highlights the importance of accurately monitoring Greenland's small peripheral glaciers. These small peripheral glaciers appear poised to play an outsized role in Greenland ice loss for decades to come. Key Points: Greenland peripheral glacier mass loss increased from 27.2 Gt/yr (February 2003–October 2009) to 42.3 Gt/yr (October 2018–December 2021Mass loss increased by a factor of four for peripheral glaciers in North Greenland during February 2003–December 2021Enhanced precipitation in northeast Greenland during October 2018–December 2021 resulted in ice thickening at higher elevations [ABSTRACT FROM AUTHOR]

We present a novel method to estimate dynamic ice loss of Greenland's three largest outlet glaciers: Jakobshavn Isbræ, Kangerlussuaq Glacier, and Helheim Glacier. We use Global Navigation Satellite System (GNSS) stations attached to bedrock to measure elastic displacements of the solid Earth caused by dynamic thinning near the glacier terminus. When we compare our results with discharge, we find a time lag between glacier speedup/slowdown and onset of dynamic thinning/thickening. Our results show that dynamic thinning/thickening on Jakobshavn Isbræ occurs 0.87 ± 0.07 years before speedup/slowdown. This implies that using GNSS time series we are able to predict speedup/slowdown of Jakobshavn Isbræ by up to 10.4 months. For Kangerlussuaq Glacier the lag between thinning/thickening and speedup/slowdown is 0.37 ± 0.17 years (4.4 months). Our methodology and results could be important for studies that attempt to model and understand mechanisms controlling short‐term dynamic fluctuations of outlet glaciers in Greenland. Plain Language Summary: A wide range of sensors and methods have been used to study the changes of the Greenland Ice Sheet, including satellite gravimetry, altimetry, and the input‐output method. Here, we present a novel fourth method to estimate dynamic ice loss of Greenland's three largest outlet glaciers: Jakobshavn Isbræ, Kangerlussuaq Glacier, and Helheim Glacier. We use Global Navigation Satellite System (GNSS) stations attached to bedrock to measure rise of land masses caused by ongoing ice mass loss near the glacier terminus. When we compare our results with ice discharge, we find a time lag between glacier speedup/slowdown and onset of dynamic induced thinning/thickening. Our results show that dynamic thinning/thickening on Jakobshavn Isbræ occurs 0.87 ± 0.07 years before speedup/slowdown. This implies that using GNSS uplift time series we are able to predict ice flow speedup/slowdown of Jakobshavn Isbræ by up to 10 months. For Kangerlussuaq Glacier and Helheim Glacier the lag between thinning/thickening and speedup/slowdown is 0.37 ± 0.17 years (4.4 months) and 0.03 ± 0.16 years, respectively. Our methodology and results could be important for studies that attempt to model and understand mechanisms controlling short‐term dynamic fluctuations of outlet glaciers in Greenland. Key Points: A novel method to estimate dynamic ice loss of Greenland's three largest outlet glaciers, Jakobshavn, Kangerlussuaq, and Helheim glacierDynamic thinning/thickening occurs 0.87 ± 0.07 years before speedup/slowdown at Jakobshavn IsbræA similar time lag between change in uplift rate and flow speed change allows us to predict future ice discharge from past uplift [ABSTRACT FROM AUTHOR]

Heat transport via ocean currents can affect the melting of marine‐terminating glaciers in Greenland. Studying past changes of marine‐terminating glaciers allows assessing the regional sensitivity of the Greenland Ice Sheet to ocean temperature changes in the context of a warming ocean. Here, we present a high‐resolution multiproxy marine sediment core study from Skjoldungen Fjord, close to the marine‐terminating Thrym Glacier. Grain‐size data are obtained to reconstruct the calving activity of Thrym Glacier; sortable silt is used as a proxy for fjord water circulation, and sea surface temperatures (SSTs) are reconstructed from alkenone paleothermometry (Uk'37). Measurements of 210Pb, 137Cs, and 14C indicate that the core covers the past 220 years (1796–2013 CE). Comparisons with modeled SST data (Hadley Centre Sea Ice and SST) and instrumental temperatures (International Council for the Exploration of the Sea) suggest that the SST proxy record reflects temperature variability of the surface waters over the shelf and that alkenones are advected into the fjord. Additionally, average temperatures and the amplitude of fluctuations are influenced by alkenones advected from upstream the Irminger Current. We find that the SST record compares well with other alkenone‐based reconstructions from SE‐Greenland and thus features regional shelf water variability. The calving activity as well as the terminus position of Thrym Glacier did not seem to respond to the SST variability. Limited ice‐ocean interactions owing to the specific setting of the glacier would explain this. Instead, the fjord circulation may have been influenced by enhanced meltwater production as well as to larger scale changes in the Atlantic Meridional Overturning Circulation. Key Points: Alkenone‐based sea surface temperature reconstructions reveal common SE‐Greenland shelf variability during the 20th centuryIncreasing ocean temperature did not result in a retreat of Thrym GlacierSortable silt parameters indicate that fjord water column flow is influenced by increased meltwater release and/or shelf water circulation [ABSTRACT FROM AUTHOR]

• Geodetic data and model reveal transient mass changes in Greenland. • NW Greenland exhibited different change patterns than the rest subregions. • Precipitation anomalies were opposite in signs in east & west Greenland. • Atmospheric circulation anomalies may cause most of the transient mass changes. Much of the research to understand the ice mass changes of Greenland ice sheet (GrIS) has focused on detecting linear rates and accelerations at decadal or longer periods. The transient (short-term, non-secular) mass changes show large variability, and if not properly accounted for, can introduce significant biases into estimates of long-term ice mass loss rates and accelerations. Despite the growing number of geodetic observations, in terms of spatial coverage, types of observables, and the extent of the time series, studies of the transient mass changes over GrIS are lacking. To address this limitation, we apply multi-channel singular spectral analysis to the Gravity Recovery and Climate Experiment (GRACE) mass concentrations (mascon), surface mass balance (SMB) model output, and ice discharge data, to determine the transient mass changes over Greenland over the decade (2007 to 2017). The goal of this analysis is to elucidate the spatio-temporal variability of the ice mass change. For the entire GrIS, both the mascon and SMB transient mass changes are characterized by a sustained mass gain from late 2007 to early 2010, a sustained mass loss from early 2010 to early 2013, and a mass gain from early 2013 to mid-2015. Global Positioning System sites deployed along the coast of Greenland showed uplift from early 2010 to early 2013 and subsidence from early 2013 to 2015, consistent with the corresponding ice mass loss and gain of the entire GrIS. The peak-to-peak amplitude of the transient mass change was estimated to be −294 ± 27 Gt from GRACE mascons and -252 ± 16 Gt from the SMB where the latter value includes the effect of ice discharge. The transient mass change due to ice discharge accounted for less than 10% of the total transient mass change. Our regional assessment reveals that the central-west, southwest, northeast, and southeast regions display similar time-varying patterns as we found for the entire GrIS, but the north and northwest regions show different patterns. Atmospheric circulation anomalies as measured by the Greenland Blocking Index (GBI) are able to explain most of these transient anomalies. More specifically, high-GBI-associated high temperature was one of the main reasons for the transient mass loss of the entire GrIS during 2010-2012 while low GBI can explain the transient mass gain during 2013-2015. Contrasting behaviors of precipitation anomalies in east and west Greenland under abnormally high or low GBI conditions may explain the different patterns of the transient mass change in the northwest and the rest of Greenland. [ABSTRACT FROM AUTHOR]