The projected demise of Barnes Ice Cap: Evidence of an unusually warm 21st century Arctic

Abstract

As a remnant of the Laurentide Ice Sheet, Barnes Ice Cap owes its existence and present form in part to the climate of the last glacial period. The ice cap has been sustained in the present interglacial climate by its own topography through the mass balance‐elevation feedback. A coupled mass balance and ice‐flow model, forced by Coupled Model Intercomparison Project Phase 5 climate model output, projects that the current ice cap will likely disappear in the next 300 years. For greenhouse gas Representative Concentration Pathways of +2.6 to +8.5 Wm−2, the projected ice‐cap survival times range from 150 to 530 years. Measured concentrations of cosmogenic radionuclides 10Be, 26Al, and 14C at sites exposed near the ice‐cap margin suggest the pending disappearance of Barnes Ice Cap is very unusual in the last million years. The data and models together point to an exceptionally warm 21st century Arctic climate.

Six Decades of Glacial Mass Loss in the Canadian Arctic Archipelago

“…Figure 12d also suggests that a 2 ∘ C summer warming will lead to an ∼30% decrease in solid precipitation and would terminate all liquid water retention at Barnes ice cap. In a recent study, Gilbert et al (2017) predicted the total disappearance of Barnes ice cap in the next 300 years. Figure 13 shows the sensitivity of NCAA (blue) and SCAA (red) SMB to summer warming with respect to the 1958-1995 period.…”

“…Covering an area of ∼5,900 km 2 , Barnes ice cap is another remnant of the Laurentide ice sheet (Gilbert et al, ) that is located ∼400 km to the northwest of Penny ice cap. It comprises three main domes, with a maximum ice thickness of 550 m (Clough & Løken, ) and is surrounded by outlet glaciers terminating in proglacial lakes.…”

Supraglacial rivers on the northwest Greenland Ice Sheet, Devon Ice Cap, and Barnes Ice Cap mapped using Sentinel-2 imagery

“…The Barnes Ice Cap (BIC) is a remnant of the Laurentide Ice Sheet (Gilbert et al, 2016) (Figure 1). The BIC is very sensitive to Arctic climate change and is predicted to disappear in the next 300 years (Gilbert et al, 2017). Like the DIC, the BIC also has a dome-like shape but its ice divide mainly runs northwestsoutheast ( Figure 4).…”

“…Like the DIC, the BIC also has a dome-like shape but its ice divide mainly runs northwestsoutheast ( Figure 4). Research on the BIC has focused mainly on its accelerated melting and thinning in response to climate warming and internal dynamics (Dupont et al, 2012;Gilbert et al, 2016;Gilbert et al, 2017). BIC hydrology, in contrast, has received scant attention and to our knowledge, no study of BIC supraglacial streams and rivers has been conducted to date.…”

Rapidly receding Arctic Canada glaciers revealing landscapes continuously ice-covered for more than 40,000 years

“…Paleotemperature reconstructions from Greenland and Baffin Island show that the most recent time prior to the Holocene with temperatures similar to present was during the Last Interglaciation, suggesting that that these landscapes are now ice-free for the first time in ~115 ka and that modern temperatures represent the warmest century in 115 ka, despite relatively low local summer insolation. These trends are likely to continue and remove all ice from Baffin Island within the next few centuries, even in the absence of additional summer warming 4,35 .…”