Two of Antarctica’s most important glaciers which together cover area the size of Norway are crumbling faster than ever, satellite images reveal
- Researchers studied the evolution of the Pine Island and Thwaites glaciers
- Their melting is responsible for around 5 per cent of global sea level rise to date
- However, their total collapse would raise global sea levels by a total of 3.3 feet
- The team found fracturing weakens the ice sheet — allowing yet more damage
Two key glaciers in Antarctica — which together cover an area the size of Norway — are fracturing faster than ever before, an analysis of satellite images has revealed.
An international team of experts warned that the Pine Island and Thwaites Glaciers — on the Amundsen Sea Embayment — are on the path to disintegrating.
Pine Island and Thwaites are among the continent’s most dynamic glaciers — and their melting is responsible for some 5 per cent of global sea level rise to date.
Their complete loss, however — driven by the warming of the surrounding waters —would raise global sea levels by a whopping 3.3 feet.
Predicting the evolution of the Pine Island and Thwaites glaciers is therefore vital to understanding the future of our warming planet’s seas.
Two key glaciers in Antarctica — which together cover an area the size of Norway — are fracturing faster than ever before, an analysis of satellite images has revealed. Pictured, an image of the Pine Island glacier, as seen in late 2017, with a developing fracture highlighted
‘To reveal what’s really going on at Pine Island and Thwaites, we dug into imaging data from a number of different satellites,’ said paper author and geoscientist Stef Lhermitte of the Delft University of Technology in the Netherlands.
‘We found structural damage at the “shear margins” of the glaciers’ ice shelves, where the ice transitions from fast- to slow-moving — large crevasses, rifts and open fractures that indicate that the ice shelves are slowly tearing apart.’
‘Currently, the ice shelves are a little like a slow car in traffic — they force anything behind them to slow down. Once they’re removed, ice sitting further inland will be able to speed up, which in turn will cause sea levels to rise even faster.’
Crevasses were not seen in images of the ice taken back in 1997 — and the damage appeared far less widespread even in observations from just 2016 — suggesting that the deterioration has been accelerating over the last two decades.
Satellite data was collected by various missions — including the European Space Agency’s CryoSat and Copernicus Sentinel-1, as well as the NASA/USGS Landsat program and the Japanese ASTER instrument aboard NASA’s Terra satellite.
The team tracked the spreading fractures, determined how the topography of the ice shelf and glacier had changed and assessed the speed at which the ice had been moving — from which they could model the impact of the damaged margins.
‘This fracturing appears to kick off a feedback process — it preconditions the ice shelves to disintegrate,’ said paper author Thomas Nagler of Environmental Earth Observation Information Technology (ENVEO) in Innsbruck, Austria.
‘As the glaciers fracture at their weak points this damage speeds up, spreads, and weakens more of the ice shelves, causing further deterioration — and making it more likely that the shelves will start crumbling apart even faster.’
‘The results from this study highlight a pressing need to include such feedback processes in model projections of ice shelf retreat, ice sheet mass loss and sea level change,’ said European Space Agency CryoSat Mission Scientist, Mark Drinkwater.
‘We know that a significant amount of glacial ice in West Antarctica is currently being affected by climate change — in fact, a recent study found 24 per cent of this ice to be rapidly thinning and unstable.’
‘These new results underline just how quickly this damage is occurring, and reveal that Pine Island and Thwaites Glaciers are more vulnerable than ever before.’
The full findings of the study were published in the Proceedings of the National Academy of Science.
An international team of experts warned that the Pine Island and Thwaites Glaciers — on the Amundsen Sea Embayment — are on the path to disintegrating
GLACIERS AND ICE SHEETS MELTING WOULD HAVE A ‘DRAMATIC IMPACT’ ON GLOBAL SEA LEVELS
Global sea levels could rise as much as 10ft (3 metres) if the Thwaites Glacier in West Antarctica collapses.
Sea level rises threaten cities from Shanghai to London, to low-lying swathes of Florida or Bangladesh, and to entire nations such as the Maldives.
In the UK, for instance, a rise of 6.7ft (2 metres) or more may cause areas such as Hull, Peterborough, Portsmouth and parts of east London and the Thames Estuary at risk of becoming submerged.
The collapse of the glacier, which could begin with decades, could also submerge major cities such as New York and Sydney.
Parts of New Orleans, Houston and Miami in the south on the US would also be particularly hard hit.
A 2014 study looked by the union of concerned scientists looked at 52 sea level indicators in communities across the US.
It found tidal flooding will dramatically increase in many East and Gulf Coast locations, based on a conservative estimate of predicted sea level increases based on current data.
The results showed that most of these communities will experience a steep increase in the number and severity of tidal flooding events over the coming decades.
By 2030, more than half of the 52 communities studied are projected to experience, on average, at least 24 tidal floods per year in exposed areas, assuming moderate sea level rise projections. Twenty of these communities could see a tripling or more in tidal flooding events.
The mid-Atlantic coast is expected to see some of the greatest increases in flood frequency. Places such as Annapolis, Maryland and Washington, DC can expect more than 150 tidal floods a year, and several locations in New Jersey could see 80 tidal floods or more.
In the UK, a two metre (6.5 ft) rise by 2040 would see large parts of Kent almost completely submerged, according to the results of a paper published in Proceedings of the National Academy of Science in November 2016.
Areas on the south coast like Portsmouth, as well as Cambridge and Peterborough would also be heavily affected.
Cities and towns around the Humber estuary, such as Hull, Scunthorpe and Grimsby would also experience intense flooding.
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