From The University of Leeds (UK): “Billions of tonnes of ice lost from Antarctic Ice sheet”
From The University of Leeds (UK)
3.20.23
David Lewis
d.lewis@leeds.ac.uk
Scientists have calculated that the fastest changing Antarctic region - the Amundsen Sea Embayment - has lost more than 3000 billion tonnes of ice over a 25-year period.
If all the lost ice was piled on London, it would stand over 2 km tall - or 7.4 times the height of the Shard. If it were to cover Manhattan, it would stand at 61 km – or 137 Empire State Buildings placed on top of one another.
Twenty major glaciers form the Amundsen Sea Embayment in West Antarctica, which is more than four times the size of the UK, and they play a key role in contributing to the level of the world’s oceans.
So much water is held in the snow and ice, that if it were to all to drain into the sea, global sea levels could increase by more than one metre.
The research, led by Dr Benjamin Davison at the University of Leeds, calculated the “mass balance” of the Amundsen Sea Embayment. This describes the balance between mass of snow and ice gain due to snowfall and mass lost through calving, where icebergs form at the end of a glacier and drift out to sea.
When calving happens faster than the ice is replaced by snowfall, then the Embayment loses mass overall and contributes to global sea level rise. Similarly, when snowfall supply drops, the Embayment can lose mass overall and contribute to sea level rise.
The results show that West Antarctica saw a net decline of 3,331 billion tonnes of ice between 1996 and 2021, contributing over nine millimetres to global sea levels. Changes in ocean temperature and currents are thought to have been the most important factors driving the loss of ice.
Dr Davison, a Research Fellow at the Institute for Climate and Atmospheric Science at Leeds, said: “The 20 glaciers in West Antarctica have lost an awful lot of ice over the last quarter of a century and there is no sign that the process is going to reverse anytime soon although there were periods where the rate of mass loss did ease slightly.
“Scientists are monitoring what is happening in the Amundsen Sea Embayment because of the crucial role it plays in sea-level rise. If ocean levels were to rise significantly in future years, there are communities around the world who would experience extreme flooding.”
The research has been published in the scientific journal Nature Communications [below].
Iceberg floating from the Amundsen Sea Embayment. ULeeds.
Extreme snowfall events
Using climate models that show how air currents move around the world, the scientists identified that the Amundsen Sea Embayment had experienced several extreme snowfall events over the 25-year study period.
These would have resulted in periods of heavy snowfall and periods of very little snowfall or a “snow drought”.
The researchers factored these extreme events into their calculations. Surprisingly, they found that these events contributed up to half of the ice change at certain times, and therefore played a key role in the contribution the Amundsen Sea Embayment was making to sea level rise during certain time periods.
For example, between 2009 and 2013, the models revealed a period of a persistent snow drought. The lack of snowfall starved the ice sheet and caused it to lose ice, therefore contributing about 25% more to sea level rise than in years of average snowfall.
In contrast, during the winters of 2019 and 2020 there was very heavy snowfall. The scientists estimated that this heavy snowfall mitigated the sea level contribution from the Amundsen Sea Embayment, reducing it to about half of what it would have been in an average year.
Dr Davison said: “Changes in ocean temperature and circulation appear to be driving the long-term, large-scale changes in West Antarctica ice sheet mass. We absolutely need to research those more because they are likely to control the overall sea level contribution from West Antarctica.
“However, we were really surprised to see just how much periods of extremely low or high snowfall could affect the ice sheet over two to five-year periods – so much so that we think they could play an important, albeit secondary role, in controlling rates of West Antarctic ice loss.”
Dr Pierre Dutrieux, a scientist at the British Antarctic Survey and co-author of the study, added: “Ocean temperature changes and glacial dynamics appear strongly connected in this part of the world, but this work highlights the large variability and unexpected processes by which snowfall also plays a direct role in modulating glacier mass.”
New glacier named
The ice loss from the region over the past 25 years has seen the retreat of the Pine Island Glacier, also known as PIG.
As it retreated, one of its tributary glaciers became detached from the main glacier and rapidly accelerated. As a result, the tributary glacier has now been named by the UK Antarctic Place-names Committee, Piglet Glacier, so that it can be unambiguously located and identified by future studies.
Dr Anna Hogg, one of the authors of the paper and Associate Professor at the Institute of Climate and Atmospheric Science at Leeds, said: “As well as shedding new light on the role of extreme snowfall variability on ice sheet mass changes, this research also provides new estimates of how quickly this important region of Antarctica is contributing to sea level rise.
“Satellite observations have showed that the newly named Piglet Glacier accelerated its ice speed by 40%, as the larger PIG retreated to its smallest extent since records began.”
Satellites such as the Copernicus Sentinel-1 satellite, which uses sensors that ‘see’ through cloud even during the long Polar night, have transformed our ability to monitor remote regions.
It is essential to have frequent measurements of change in ice speed and iceberg calving, so that we can monitor the incredibly rapid change taking place in Antarctica.
Nature Communications
See the science paper for instructive material with images.
See the full article here.
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The University of Leeds is a public research university in Leeds, West Yorkshire, England. It was established in 1874 as the Yorkshire College of Science. In 1884 it merged with the Leeds School of Medicine (established 1831) and was renamed Yorkshire College. It became part of the federal Victoria University in 1887, joining Owens College (which became The University of Manchester (UK)) and University College Liverpool (which became The University of Liverpool (UK)). In 1904 a royal charter was granted to the University of Leeds by King Edward VII.
The university has 36,330 students, the 5th largest university in the UK (out of 169). From 2006 to present, the university has consistently been ranked within the top 5 (alongside the University of Manchester, The Manchester Metropolitan University (UK), The University of Nottingham (UK) and The University of Edinburgh (SCT)) in the United Kingdom for the number of applications received. Leeds had an income of £751.7 million in 2020/21, of which £130.1 million was from research grants and contracts. The university has financial endowments of £90.5 million (2020–21), ranking outside the top ten British universities by financial endowment.
Notable alumni include current Leader of the Labour Party Keir Starmer, former Secretary of State Jack Straw, former co-chairman of the Conservative Party Sayeeda Warsi, Piers Sellers (NASA astronaut) and six Nobel laureates.
The university’s history is linked to the development of Leeds as an international centre for the textile industry and clothing manufacture in the United Kingdom during the Victorian era. The university’s roots can be traced back to the formation of schools of medicine in English cities to serve the general public.
Before 1900, only six universities had been established in England and Wales: The University of Oxford (UK) (founded c. 1096–1201), The University of Cambridge (UK) (c. 1201), The University of London (UK) (1836), The University of Durham (UK) (1837), Victoria University (UK) (1880), and The University of Wales Trinity Saint David[ Prifysgol Cymru Y Drindod Dewi Sant](WLS) (1893).
The Victoria University was established in Manchester in 1880 as a federal university in the North of England, instead of the government elevating Owens College to a university and grant it a royal charter. Owens College was the sole college of Victoria University from 1880 to 1884; in 1887 Yorkshire College was the third to join the university.
Leeds was given its first university in 1887 when the Yorkshire College joined the federal Victoria University on 3 November. The Victoria University had been established by royal charter in 1880; Owens College being at first the only member college. Leeds now found itself in an educational union with close social cousins from Manchester and Liverpool.
Unlike Owens College, the Leeds campus of the Victoria University had never barred women from its courses. However, it was not until special facilities were provided at the Day Training College in 1896 that women began enrolling in significant numbers. The first female student to begin a course at the university was Lilias Annie Clark, who studied Modern Literature and Education.
The Victoria (Leeds) University was a short-lived concept, as the multiple university locations in Manchester and Liverpool were keen to establish themselves as separate, independent universities. This was partially due to the benefits a university had for the cities of Liverpool and Manchester whilst the institutions were also unhappy with the practical difficulties posed by maintaining a federal arrangement across broad distances. The interests of the universities and respective cities in creating independent institutions was further spurred by the granting of a charter to the University of Birmingham in 1900 after lobbying from Joseph Chamberlain.
Following a Royal Charter and Act of Parliament in 1903, the then newly formed University of Liverpool began the fragmentation of the Victoria University by being the first member to gain independence. The University of Leeds soon followed suit and had been granted a royal charter as an independent body by King Edward VII by 1904.
The Victoria University continued after the break-up of the group, with an amended constitution and renamed as the Victoria University of Manchester (though “Victoria” was usually omitted from its name except in formal usage) until September 2004. On 1 October 2004 a merger with the University of Manchester Institute of Science and Technology was enacted to form The University of Manchester.
In December 2004, financial pressures forced the university’s governing body (the Council) to decide to close the Bretton campus. Activities at Bretton were moved to the main university campus in the summer of 2007 (allowing all Bretton-based students to complete their studies there). There was substantial opposition to the closure by the Bretton students. The university’s other satellite site, Manygates in Wakefield, also closed, but Lifelong Learning and Healthcare programmes are continuing on a new site next to Wakefield College.
In May 2006, the university began re-branding itself to consolidate its visual identity to promote one consistent image. A new logo was produced, based on that used during the centenary celebrations in 2004, to replace the combined use of the modified university arms and the Parkinson Building, which has been in use since 2004. The university arms will still be used in its original form for ceremonial purposes only. Four university colours were also specified as being green, red, black and beige.
Leeds provides the local community with over 2,000 university student volunteers. With 8,700 staff employed in 2019-20, the university is the third largest employer in Leeds and contributes around £1.23bn a year to the local economy – students add a further £211m through rents and living costs.
The university’s educational partnerships have included providing formal accreditation of degree awards to The Leeds Arts University (UK) and The Leeds Trinity University (UK), although the latter now has the power to award its own degrees. The College of the Resurrection, an Anglican theological college in Mirfield with monastic roots, has, since its inception in 1904, been affiliated to the university, and ties remain close. The university is also a founding member of The Northern Consortium (UK).
In August 2010, the university was one of the most targeted institutions by students entering the UCAS clearing process for 2010 admission, which matches undersubscribed courses to students who did not meet their firm or insurance choices. The university was one of nine The Russell Group Association(UK) universities offering extremely limited places to “exceptional” students after the universities in Birmingham, Bristol, Cambridge, Edinburgh and Oxford declared they would not enter the process due to courses being full to capacity.
On 12 October 2010, The Refectory of the Leeds University Union hosted a live edition of the Channel 4 News, with students, academics and economists expressing their reaction to the Browne Review, an independent review of Higher Education funding and student finance conducted by John Browne, Baron Browne of Madingley. University of Leeds Vice-Chancellor and Russell Group chairman Michael Arthur participated, giving an academic perspective alongside current vice-chancellor of The Kingston University (UK) and former Pro Vice-Chancellor and Professor of Education at the University of Leeds, Sir Peter Scott. Midway through the broadcast a small group of protesters against the potential rise of student debt entered the building before being restrained and evacuated.
In 2016, The University of Leeds became University of the Year 2017 in The Times and The Sunday Times’ Good University Guide. The university has risen to 13th place overall, which reflects impressive results in student experience, high entry standards, services and facilities, and graduate prospects.
In 2018, the global world ranking of the University of Leeds is No.93. There are currently 30,842 students are studying in this university. The average tuition fee is 12,000 – US$14,000.
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Many of the academic departments have specialist research facilities, for use by staff and students to support research from internationally significant collections in university libraries to state-of-the-art laboratories. These include those hosted at the Institute for Transport Studies, such as the University of Leeds Driving Simulator which is one of the most advanced worldwide in a research environment, allowing transport researchers to watch driver behaviour in accurately controlled laboratory conditions without the risks associated with a live, physical environment.
With extensive links to the St James’s University Hospital through the Leeds School of Medicine, the university operates a range of high-tech research laboratories for biomedical and physical sciences, food and engineering – including clean rooms for bionanotechnology and plant science greenhouses. The university is connected to Leeds General Infirmary and the institute of molecular medicine based at St James’s University Hospital which aids integration of research and practice in the medical field.
The university also operate research facilities in the aviation field, with the Airbus A320 flight simulator. The simulator was devised with an aim to promote the safety and efficiency of flight operations; where students use the simulator to develop their reactions to critical situations such as engine failure, display malfunctioning and freak weather.
In addition to these facilities, many university departments conduct research in their respective fields. There are also various research centres, including Leeds University Centre for African Studies.
Leeds was ranked joint 19th (along with The University of St Andrews (SCT)) amongst multi-faculty institutions in the UK for the quality (GPA) of its research and 10th for its Research Power in the 2014 Research Excellence Framework.
Between 2014-15, Leeds was ranked as the 10th most targeted British university by graduate employers, a two place decrease from 8th position in the previous 2014 rankings.
The 2021 The Times Higher Education World University Rankings ranked Leeds as 153rd in the world. The university ranks 84th in the world in the CWTS Leiden Ranking. Leeds is ranked 91st in the world (and 15th in the UK) in the 2021 QS World University Rankings.
The university won the biennially awarded Queen’s Anniversary Prize in 2009 for services to engineering and technology. The honour being awarded to the university’s Institute for Transport Studies (ITS) which for over forty years has been a world leader in transport teaching and research.
The university is a founding member of The Russell Group Association(UK), comprising the leading research-intensive universities in the UK, as well as the N8 Group for research collaboration, The Worldwide Universities Network (UK), The Association of Commonwealth Universities (UK), The European University Association (EU), The White Rose University Consortium (UK), the Santander Network and the CDIO Initiative. It is also affiliated to The Universities (UK). The Leeds University Business School holds the ‘Triple Crown’ of accreditations from the Association to Advance Collegiate Schools of Business, the Association of MBAs and the European Quality Improvement System.
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