Short- and long-term variability of the Antarctic and Greenland ice sheets

Abstract

The variability of Antarctic Ice Sheet and Greenland Ice Sheet occurs in various timescales and is important for projections of sea level rise; however, there are substantial uncertainties concerning future ice sheet mass changes. In this Review, we explore the degree to which shortterm fluctuations and extreme glaciological events reflect the ice sheets' long-term evolution and response to ongoing climate change. Short-term (decadal or shorter) variations in atmospheric or oceanic conditions can trigger amplifying feedbacks that increase the sensitivity of ice sheets to climate change. For example, variability in ocean-induced and atmosphere-induced melting can trigger ice thinning, retreat and/or collapse of ice shelves, grounding-line retreat, and ice flow acceleration. Antarctica is especially prone to increased melting and ice sheet collapse from warm ocean currents, which could be accentuated with increased climate variability. In Greenland both high and low melt anomalies have been observed since 2012, highlighting the influence of increased interannual climate variability on extreme glaciological events and ice sheet evolution. Failing to adequately account for such variability can result in biased projections of multi-decadal ice mass loss. Therefore, future research should aim to improve climate and ocean observations and models, and develop sophisticated ice sheet models that are directly constrained by observational records and can capture ice dynamical changes across various timescales.Sections 'weather' from 'climate' changes. Oceanic forcingOceanic forcing drives ice sheet mass loss by melting marine-terminating glaciers and ice shelves (Fig. 2). Both the GrIS and AIS exhibit interannual-scale to decadal-scale variability in response to oceanic forcing, potentially related to internal climate variability 34,35 . In Greenland, for example, such oceanic forcing has been implicated in the multi-decadal retreat and thinning of several coastal Related linksArgo: https://argo.ucsd.edu/

High-resolution elevation models of Larsen B glaciers extracted from 1960s imagery

“…This aligns with other measures of glacier stability pre-ice shelf collapse 14 , 19 , 38 , 58 . We add new measurements of total thinning and grounded ice loss over the multi-decadal scale period 1968–2021 (Table 1 ) which will be vital for improving confidence in longer-term mass balance models of the Antarctic Peninsula 27 . Our detailed maps of elevation differences between 1968 and 2021 depict the net magnitude and spatial pattern of drawdown and represents previously reported short term responses from Larsen B tributary glaciers 18 – 20 , 22 , 24 , 46 , 51 .…”

“…Quantifying the ice loss and contribution to sea-level rise over multi-decadal timescales is important for climate-sensitive areas like the Antarctic Peninsula 26 , 27 . However, long observational timeseries are rare due to difficult field conditions and persistent cloud cover that interferes with satellite measurements.…”

Distinct Central and Eastern Pacific El Niño Influence on Antarctic Surface Mass Balance

“…The Antarctic Ice Sheet (AIS) has been losing mass for several decades due to regional ocean-driven increases in basal melting of ice shelves, iceberg calving and associated dynamic changes in ice discharge (Frieler et al, 2015;Fox-Kemper et al, 2021;Hanna et al, 2020Hanna et al, , 2024; J.-Y. .…”