Nav: Home

Antarctic Peninsula ice more stable than thought

May 02, 2017

Glacier flow at the southern Antarctic Peninsula has increased since the 1990s, but a new study has found the change to be only a third of what was recently reported.

An international team of researchers, led by the UK Centre for Polar Observation and Modelling at the University of Leeds, are the first to map the change in ice speed. The team collated measurements recorded by five different satellites to track changes in the speed of more than 30 glaciers since 1992.

The findings, published today in Geophysical Research Letters, represent the first detailed assessment of changing glacier flow in Western Palmer Land -- the southwestern corner of the Antarctic Peninsula.

The new Leeds led research calls into question a recent study from the University of Bristol that reported 45 cubic kilometres per year increase in ice loss from the sector. The Leeds research found the increase to be three times smaller.

Lead author Dr Anna Hogg, from the Leeds' School of Earth and Environment, said: "Dramatic changes have been reported in this part of Antarctica, so we took a closer look at how its glaciers have evolved using 25 years of satellite measurements dating back to the early 1990s."

The researchers found that between 1992 and 2016, the flow of most of the region's glaciers increased by between 20 and 30 centimetres per day, equating to an average 13% speedup across the glaciers of Western Palmer Land as a whole.

These measurements provide the first direct evidence that Western Palmer Land is losing ice due to increased glacier flow -- a process known as dynamical imbalance.

The team also combined their satellite observations with an ice flow model using data assimilation to fill in gaps where the satellites were unable to produce measurements. This allowed the complete pattern of ice flow to be mapped, revealing that the regions glaciers are now pouring an additional 15 cubic kilometres of ice into the oceans each year compared to the 1990s.

The earlier study reported that the region was losing three times this amount of ice, based on measurements of glacier thinning and mass loss determined from other satellite measurements. The Leeds study casts doubt on that interpretation, because the degree of glacier speedup is far too small.

Study co-author Professor Andrew Shepherd, from Leeds' School of Earth and Environment, explained: "Although Western Palmer Land holds a lot of ice -- enough to raise global sea levels by 20 centimetres -- its glaciers can't be responsible for a major contribution to sea level rise, because their speed has barely changed over the past 25 years. It's possible that it has snowed less in this part of Antarctica in recent years -- that would also cause the glaciers to thin and lose mass, but it's a not a signal of dynamical imbalance."

The greatest speedup in flow was observed at glaciers that were grounded at depths more than 300 m below the ocean surface.

Dr Hogg said: "We looked at water temperatures in front of the glaciers which have sped up the most, and we found that they flow through deep bedrock channels into the warmest layer of the ocean. This circumpolar deep water, which is relatively warm and salty compared to other parts of the Southern Ocean, has warmed and shoaled in recent decades, and can melt ice at the base of glaciers which reduces friction and allows them to flow more freely.

With much of Western Palmer Land's ice mass lying well below sea level it is important to monitor how remote areas such as this, are responding to climate change. Satellites are the perfect tool to do this.

Pierre Potin, ESA's Manager of the Copernicus Sentinel-1 Mission which was used in the study, said: "We will continue to use Sentinel-1's all weather, day-night imaging capability to extend the long term climate data record from European satellites."
-end-
Further information:

Images available for download: goo.gl/Dwg1Ed

Image1 caption: Ice speed in Western Palmer Land on the Antarctic Peninsula measured by the ESA-EU Sentinel-1 satellite mission.
Credit: J. Wuite, ENVEO.

Image 2 caption: View of Western Palmer Land glaciers and George VI Ice Shelf from BAS Twin Otter aeroplane.
Credit: Hogg/CPOM.

Additional images

Caption: View from the British Antarctic Survey (BAS) Rothera research station, on Alexander Island at the Antarctic Peninsula.
Credit: A. E. Hogg/CPOM

Video available for download: goo.gl/5CDNrB

(Animation of the ice speed evolving through the study period)

Caption: Ice flow in Western Palmer Land from 1992 to 2016, from an optimised ice sheet model.
Credit: S. Cornford, CPOM/Univ. Swansea.

Dr Anna Hogg is available for interview.

For interviews and additional information please contact University of Leeds Media Relations Officer Anna Martinez on a.martinez@leeds.ac.uk or +44 (0)113 343 4196 Out of hours number +44 (0)7712389448

Paper reference:

Hogg, A. E., et al. (2017), Increased ice flow in Western Palmer Land linked to ocean melting, Geophys. Res. Lett., 44, (DOI:10.1002/2016GL072110)

University of Bristol study - Wouters at al., [2015] - can be found at: http://science.sciencemag.org/content/348/6237/899

University of Leeds

The University of Leeds is one of the largest higher education institutions in the UK, with more than 31,000 students from 147 different countries, and a member of the Russell Group research-intensive universities.

We are a top 10 university for research and impact power in the UK, according to the 2014 Research Excellence Framework, and positioned as one of the top 100 best universities in the world in the 2015 QS World University Rankings. We are The Times and The Sunday Times University of the Year 2017. http://www.leeds.ac.uk

Centre for Polar Observation and Modelling (CPOM) provides, on behalf of NERC, UK National Capability in observing and modelling the cryosphere. We combine satellite measurements with theoretical and numerical models to explain how Earth's ice, oceans and atmosphere interact, and to predict their behaviour over long periods and large scales.

The CPOM Directorate is based at the University of Leeds, and we have researchers at the Universities of Bristol and Reading and at University College London. CPOM is funded by the Natural Environment Research Council (NERC). We also work closely with the British Antarctic Survey (BAS), National Oceanography Centre (NOC), National Centre for Earth Observation (NCEO) and European Space Agency (ESA). http://www.cpom.org.uk

University of Leeds

Related Climate Change Articles:

Mapping the path of climate change
Predicting a major transition, such as climate change, is extremely difficult, but the probabilistic framework developed by the authors is the first step in identifying the path between a shift in two environmental states.
Small change for climate change: Time to increase research funding to save the world
A new study shows that there is a huge disproportion in the level of funding for social science research into the greatest challenge in combating global warming -- how to get individuals and societies to overcome ingrained human habits to make the changes necessary to mitigate climate change.
Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.
Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.
A CERN for climate change
In a Perspective article appearing in this week's Proceedings of the National Academy of Sciences, Tim Palmer (Oxford University), and Bjorn Stevens (Max Planck Society), critically reflect on the present state of Earth system modelling.
Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).
Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.
Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.
Could climate change cause infertility?
A number of plant and animal species could find it increasingly difficult to reproduce if climate change worsens and global temperatures become more extreme -- a stark warning highlighted by new scientific research.
Predicting climate change
Thomas Crowther, ETH Zurich identifies long-disappeared forests available for restoration across the world.
More Climate Change News and Climate Change Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.