Holocene melting of the West Antarctic Ice Sheet driven by tropical Pacific warming

Abstract

The primary Antarctic contribution to modern sea-level rise is glacial discharge from the Amundsen Sea sector of the West Antarctic Ice Sheet. The main processes responsible for ice mass loss include: (1) ocean-driven melting of ice shelves by upwelling of warm water onto the continental shelf; and (2) atmospheric-driven surface melting of glaciers along the Antarctic coast. Understanding the relative influence of these processes on glacial stability is imperative to predicting sea-level rise. Employing a beryllium isotope-based reconstruction of ice-shelf history, we demonstrate that glaciers flowing into the Amundsen Sea Embayment underwent melting and retreat between 9 and 6 thousand years ago. Despite warm ocean water influence, this melting event was mainly forced by atmospheric circulation changes over continental West Antarctica, linked via a Rossby wave train to tropical Pacific Ocean warming. This millennial-scale glacial history may be used to validate contemporary ice-sheet models and improve sea-level projections.

High mid-Holocene accumulation rates over West Antarctica inferred from a pervasive ice-penetrating radar reflector

“…continued climatic transition from the LGM (Steig et al, 2001). Alternatively, it has been suggested that seasonal or interannual variability, such as a weaker circumpolar vortex (Van Den Broeke and Van Lipzig, 2004;Neumann et al, 2008) or teleconnections to tropical Pacific Ocean warming (Sproson et al, 2022), may also lead to such difference. We did not find evidence for significant changes in accumulation patterns between the mid-Holocene and modern times, suggesting that the current spatial pattern of high accumulation at the coast, decreasing inland towards the divide has been stable throughout the mid-Holocene over PIG and THW, as previously suggested by others (Siegert and Payne, 2004;Neumann et al, 2008).…”

“…While improvements in model physics and parameterisations are needed to close this gap (Bracegirdle et al, 2019;Sutter et al, 2021), a considerable improvement in the availability and quality of palaeo-proxy records, particularly during the Holocene, is also needed to gain a more accurate picture of the past ice-sheet changes (Jones et al, 2022). Palaeo-proxy data over the WAIS have traditionally come from point-based measurements, such as ice cores (WAIS Divide Project Members, 2013;McConnell et al, 2017;Buizert et al, 2021), sediment cores (Hillenbrand et al, 2013;Arnd et al, 2017;Hillenbrand et al, 2017;Kingslake et al, 2018;Venturelli et al, 2020;Neuhaus et al, 2021;Sproson et al, 2022), or from surface-exposure dating (Stone et al, 2003;Johnson et al, 2014;Hein et al, 2016;Nichols et al, 2019;Johnson et al, 2020;Braddock et al, 2022). A spatially extensive alternative data source is provided by Internal Reflecting Horizons (IRHs) sounded by RES (Bingham and Siegert, 2007;Harrison, 1973).…”

Fluctuating sea-level and reversing Monsoon winds drive Holocene lagoon infill in Southeast Asia

“…3) 15,16,32 . These dynamics are more broadly related to changing climate in the Indo-Pacific region 33 , the global effects of which extend to the high latitudes 34,35 . For the present study, it is likely that the prevailing direction of sediment transport evolved according to the new dominant wind direction.…”

Holocene Palaeoenvironmental and Palaeoproductivity Changes in the Western Amundsen Sea Embayment of Antarctica

“…Lamping et al (2020) reconstructed the dynamics of the ice shelf and sea-ice-cover in the AP during the last deglaciation on the basis of a multiproxy data set, especially evaluating the use of IPSO 25 , a biomarker for reconstructing the floating ice cover, and a biomarker for phytoplankton production. While this early Holocene environmental change has been relatively well studied (e.g., Hillenbrand et al, 2017;Larter et al, 2014), the marine records pertaining to the subsequent middle/late Holocene on the ASE are still not well understood (Johnson et al, 2014(Johnson et al, , 2021Sproson et al, 2022). Recently, Kim, Lim, et al (2021) presented a stepwise environmental shift related to large-scale climate variation, SAM and ENSO, both known to control the ocean heat content over the ASE by affecting the position of the Amundsen Sea Low (ASL) (Clem et al, 2017).…”

“…This middle/late Holocene period includes climate variations such as the Holocene Climate Optimum and cold periods observed around Antarctica. Based on beryllium isotope, Sproson et al (2022) reported that the ASE suffered melting and retreat of glaciers between 9 and 6 ka BP forced by atmospheric circulation changes over continental West Antarctica. This period coincides with the climate optimum between 7 and 5 ka BP observed from the eleven ice core records around Antarctica (Masson et al, 2000).…”