“We can see clearly now that a wave of thinning has spread rapidly across some of Antarctica’s most vulnerable glaciers, and their losses are driving up sea levels around the planet.” Andrew Shepherd, Lead author, and CPOM Director Professor
Troubling news out of Antarctica, again.
Researchers have found that nearly a quarter of the West Antarctic ice sheet is now unstable. This includes some of the largest and most vulnerable ice streams such as Thwaites and Pine Island glaciers.
From the University of Leeds:
A team of researchers, led by Professor Andy Shepherd from School of Earth and Environment at the University of Leeds, found that Antarctica's ice sheet has thinned by up to 122 metres in places, with the most rapid changes occurring in West Antarctica where ocean melting has triggered glacier imbalance.
This means that the affected glaciers are unstable as they are losing more mass through melting and iceberg calving than they are gaining through snowfall.
The team found that the pattern of glacier thinning has not been static.
Since 1992, the thinning has spread across 24% of West Antarctica and over the majority of its largest ice streams - the Pine Island and Thwaites Glaciers - which are now losing ice five times faster than they were at the start of the survey.
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They found that fluctuations in snowfall tend to drive small changes in height over large areas for a few years at a time, but the most pronounced changes in ice thickness are signals of glacier imbalance that have persisted for decades.
x25 years of satellite data show global warming affected 24% of glacier ice in West Antarctica.https://t.co/ncOcsaRXnipic.twitter.com/QAClI3CDDI
— Fercan Yalinkilic (@FercanY) May 20, 2019From the study abstract with key findings. Trends in Antarctic Ice Sheet Elevation and Mass
Fluctuations in Antarctic Ice Sheet elevation and mass occur over a variety of timescales, owing to changes in snowfall and ice flow. Here, we disentangle these signals by combining 25 years of satellite radar altimeter observations and a regional climate model. From these measurements, patterns of change that are strongly associated with glaciological events emerge. While the majority of the ice sheet has remained stable, 24% of West Antarctica is now in a state of dynamical imbalance. Thinning of the Pine Island and Thwaites glacier basins reaches 122 m in places, and their rates of ice loss are now five times greater than at the start of our survey. By partitioning elevation changes into areas of snow and ice variability, we estimate that East and West Antarctica have contributed ‐1.1±0.4 and +5.7±0.8 mm to global sea level between 1992 and 2017.
We combine satellite radar altimetry and a regional climate model to separate changes in Antarctic elevation into snow and ice contributions Between 1992 and 2017, ice thinning has grown in extent to include 24% of West Antarctica, and reaches 122 metres in places Ice losses from Pine Island and Thwaites Glaciers have risen fivefold. East and West Antarctica have contributed 4.6±1.2 mm to sea level