Antarctic Glacier's Unstable Past Reveals Danger Of Future Melting

Antarctic Glacier's Unstable Past Reveals Danger Of Future Melting Some parts of Antarctica’s Totten Glacier are more stable than others. UWA/ICECAP, Author provided

New mapping of one of the most remote areas in Antarctica has revealed regions deep within Earth’s largest ice sheet that are particularly prone to rapid melting.

Our study, published today in Nature, is focused on East Antarctica’s Totten Glacier, the outlet for the world’s largest ice catchment. The results suggest that if rising global temperatures trigger the glacier to retreat rapidly – as has happened previously in its history – this region alone could deliver sea-level rises of well over a metre over the ensuing centuries.

The Totten Glacier region is a key area for understanding the long-term vulnerability of the Antarctic Ice Sheet, but until now, knowledge of this region’s glacial history has been very limited.

Our study shows that, although the region near the coast is quite stable on timescales of several millennia, regions further inland have potential for significant and rapid retreat as the climate warms.

Specifically, we identified two stable zones where the ice sheet is not prone to rapid collapse, and two unstable zones, where it is. We have also discovered that transitions between these states have happened repeatedly during the life of the ice sheet.

Stable and not so stable

As part of the international ICECAP project, my colleagues and I used ice-penetrating radar, as well as magnetic and gravity data, to chart the rocks beneath the glacier.

By mapping the shape of the ice-sheet and its base, as well as the thickness of the rocks and sediments beneath, we were able to study the characteristic patterns of erosion left behind by the ice sheet’s previous advances and retreats – thus revealing the ice sheet’s past behaviour.

The observed patterns suggest that the ice sheet has spent much of its history in one of two configurations: either the edge has been close to the current Antarctic coast (within 150 kilometres); or it has been located some 350-550 kilometres inland. In either of these states, the ice would be relatively stable, with this glacier providing sea level fluctuations of less than a metre over the course of glacial cycles.

But the pattern of erosion also shows that melting has periodically forced the ice sheet out of either of these stable states, causing the ice sheet to collapse and retreat far inland. These events might have typically driven up global sea levels by 1.3-1.4 metres over the course of a few centuries.

Antarctic Glacier's Unstable Past Reveals Danger Of Future Melting Main image: present-day configuration of the Antarctic ice sheet surface and its base. The ice sheet surface is shaded according to surface velocity, with glaciers in red. Blue-cyan tones indicate where the ice-sheet base (or the sea floor) is below sea level, yellow-brown tones indicates where the ice sheet base is above sea level. Inset diagrams show reconstructions of the ice sheet and the coast following retreat driven by climates warmer than today’s. All images are vertically exaggerated. ICECAP Collaboration, Author provided

What is happening today?

Previous studies from satellite data have indicated that the coastal part of the Totten Glacier region and its floating ice shelf are melting rapidly. Last year, the ICECAP team discovered that there is currently warm water circulating underneath a floating portion of the glacier that is causing more melting than might have been expected.

Our results show that following a rapid loss of coastal ice due to the collapse of the floating ice shelf, this region is likely to respond more slowly than other parts of Antarctica to warming temperatures, due to the existence of a “stable zone”.

But as temperatures continue to increase, this glacier is likely to retreat into the unstable zone, and make a rapid and proportionally greater contribution to sea levels.

Our ice sheet modelling suggests that while the Totten region is not the first region in Antarctica to respond to warming climate, it is likely to become progressively more unstable as warming proceeds over hundreds to thousands of years. Ultimately this region could become the “fat end of the wedge” in terms of Antarctica’s overall contribution to rising seas, accounting for almost 15% of Antarctica’s total contribution to sea-level rise. This is likely to happen while other regions have become ice-free, or are stabilising after periods of rapid ice loss.

Antarctic Glacier's Unstable Past Reveals Danger Of Future Melting Impact of the Totten Glacier’s retreat on the Antarctic’s overall contribution to sea-level rise. The unstable retreat events in the Totten Glacier region cause significant upwards deviations of the overall Antarctic trend. SOURCE, Author provided

Our results suggest that the Totten region has severe implications for global sea level rise in warming climate conditions, especially once warming reaches the critical thresholds likely to tip the glacier out of its stable states. Given the long timescales involved for ice-sheet melting it is difficult to say with confidence when this tipping point might be reached.

Increases to carbon dioxide levels today will commit us to temperature increases that persist for thousands of years. The upper limit of the coastal stable zone could be crossed under conditions similar to those predicted for the next century, based on the higher emissions scenarios envisaged by the Intergovernmental Panel on Climate Change.The Conversation

About The Author

Alan Aitken, Assistant Professor, School of Earth and Environment, University of Western Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Related Books

Climate Change: What Everyone Needs to Know

by Joseph Romm
0190866101The essential primer on what will be the defining issue of our time, Climate Change: What Everyone Needs to Know® is a clear-eyed overview of the science, conflicts, and implications of our warming planet. From Joseph Romm, Chief Science Advisor for National Geographic's Years of Living Dangerously series and one of Rolling Stone's "100 people who are changing America," Climate Change offers user-friendly, scientifically rigorous answers to the most difficult (and commonly politicized) questions surrounding what climatologist Lonnie Thompson has deemed "a clear and present danger to civilization.". Available On Amazon

Climate Change: The Science of Global Warming and Our Energy Future second edition Edition

by Jason Smerdon
0231172834This second edition of Climate Change is an accessible and comprehensive guide to the science behind global warming. Exquisitely illustrated, the text is geared toward students at a variety of levels. Edmond A. Mathez and Jason E. Smerdon provide a broad, informative introduction to the science that underlies our understanding of the climate system and the effects of human activity on the warming of our planet.Mathez and Smerdon describe the roles that the atmosphere and ocean play in our climate, introduce the concept of radiation balance, and explain climate changes that occurred in the past. They also detail the human activities that influence the climate, such as greenhouse gas and aerosol emissions and deforestation, as well as the effects of natural phenomena.  Available On Amazon

The Science of Climate Change: A Hands-On Course

by Blair Lee, Alina Bachmann
194747300XThe Science of Climate Change: A Hands-On Course uses text and eighteen hands-on activities to explain and teach the science of global warming and climate change, how humans are responsible, and what can be done to slow or stop the rate of global warming and climate change. This book is a complete, comprehensive guide to an essential environmental topic. Subjects covered in this book include: how molecules transfer energy from the sun to warm the atmosphere, greenhouse gases, the greenhouse effect, global warming, the Industrial Revolution, the combustion reaction, feedback loops, the relationship between weather and climate, climate change, carbon sinks, extinction, carbon footprint, recycling, and alternative energy. Available On Amazon

From The Publisher:
Purchases on Amazon go to defray the cost of bringing you InnerSelf.comelf.com, MightyNatural.com, and ClimateImpactNews.com at no cost and without advertisers that track your browsing habits. Even if you click on a link but don't buy these selected products, anything else you buy in that same visit on Amazon pays us a small commission. There is no additional cost to you, so please contribute to the effort. You can also use this link to use to Amazon at any time so you can help support our efforts.

 

enafarzh-CNzh-TWnltlfrdehiiditjakomsfaptruesswsvthtrurvi

EVIDENCE

Global Temps Continue To Soar Upward As NOAA Confirms July 2019 Was Hottest Month Since Records Began In 1880
Global Temps Continue To Soar Upward As NOAA Confirms July 2019 Was Hottest Month Since Records Began In 1880
by Julia Conley
As climate scientists raise alarm over hotter and hotter global temperatures, a top U.S. weather agency reported on…
Small Nuclear War Could Bring On Global Cooling
Small Nuclear War Could Bring On Global Cooling
by Tim Radford
Smoke from Canadian forest fires was so vast it bore comparison with a nuclear bomb’s mushroom cloud – and the global…
Fossil Fuel Drilling Could Be Contributing To Climate Change By Heating Earth From Within
Fossil Fuel Drilling Could Be Contributing To Climate Change By Heating Earth From Within
by Rizwan Nawaz and Adel Sharif
Almost all scientists agree that burning fossil fuels is contributing to climate change. But agreement is less clear…
Unique Climate Change Has No Natural Cause
Unique Climate Change Has No Natural Cause
by Tim Radford
The planet is warming faster than ever, worldwide. Scientists know this unique climate change is not caused by nature.…
What Is The Future Of Climate Change?
by Simon Donner
You would think with all the chatter going on about climate that we’d all have a good understanding on the elements of…
New Research Shows That Antarctica's Largest Floating Ice Shelf Is Highly Sensitive To Warming Of The Ocean
New Research Shows That Antarctica's Largest Floating Ice Shelf Is Highly Sensitive To Warming Of The Ocean
by Dan Lowry
Scientists have long been concerned about the potential collapse of the West Antarctic Ice Sheet and its contribution…
Huge Wildfires In The Arctic And Far North Send A Planetary Warning
Huge Wildfires In The Arctic And Far North Send A Planetary Warning
by Nancy Fresco
The planet’s far North is burning. This summer, over 600 wildfires have consumed more than 2.4 million acres of forest…
Humans Cause Antarctic Ice Melt, Study Finds
Humans Cause Antarctic Ice Melt, Study Finds
by Alex Kirby
Yes, it’s us. Human activities are to blame for at least part of what’s melting the West Antarctic Ice Sheet,…

LATEST VIDEOS

What Is The Future Of Climate Change?
by Simon Donner
You would think with all the chatter going on about climate that we’d all have a good understanding on the elements of…
Why Marianne Williamson's Candidacy for President Is Important
Why Marianne Williamson's Candidacy for President Is Important
How do you know something exists if you never hear about it? How do you know about the truth, which is often "the other…
Would You Eat Meat Grown From Cells In A Laboratory? Here's How It Works
Would You Eat Meat Grown From Cells In A Laboratory? Here's How It Works
by Leigh Ackland
For many of us, eating a meal containing meat is a normal part of daily life. But if we dig deeper, some sobering…
Climate System “Getting Unhinged” as Massive Heat Wave Causes Record Melting of Greenland Ice Sheet
by Democracy Now!
The massive heat dome that shattered all-time temperature records across much of Europe last week has settled in over…
Why We're Heading For A Climate Catastrophe
by BBC Newsnight
Scientists say the world is completely off track.
A Climate Reckoning In The Heartland
by CBS News
"A historic flood in March 2019 left much of America's heartland under water. Partiularly hard-hit were Midwestern…
What Would Happen If Antarctica Melted?
by Put Put 1
"What Would Happen If Antarctica Melted?
Dr. Peter Wadhams: Arctic Research & the Methane Risk
by UPFSI
Peter Wadhams is back on ScientistsWarning.TV with a comprehensive analysis of the reticent approach that part of the…

LATEST ARTICLES

Global Temps Continue To Soar Upward As NOAA Confirms July 2019 Was Hottest Month Since Records Began In 1880
Global Temps Continue To Soar Upward As NOAA Confirms July 2019 Was Hottest Month Since Records Began In 1880
by Julia Conley
As climate scientists raise alarm over hotter and hotter global temperatures, a top U.S. weather agency reported on…
Small Nuclear War Could Bring On Global Cooling
Small Nuclear War Could Bring On Global Cooling
by Tim Radford
Smoke from Canadian forest fires was so vast it bore comparison with a nuclear bomb’s mushroom cloud – and the global…
Still Sneezing? Climate Change May Prolong Allergy Season
Still Sneezing? Climate Change May Prolong Allergy Season
by Cecilia Sierra-Heredia, et al
Every year, without fail, summer brings changes to our surroundings: more sunlight, heat, greenness and flowers, among…
Pacific Island Nations Will No Longer Stand For Australia's Inaction On Climate Change
Pacific Island Nations Will No Longer Stand For Australia's Inaction On Climate Change
by Michael O'Keefe
The Pacific Islands Forum meeting in Tuvalu this week has ended in open division over climate change.
Ocean Warming Has Fisheries On The Move, Helping Some But Hurting More
Ocean Warming Has Fisheries On The Move, Helping Some But Hurting More
by InnerSelf Staff
Climate change has been steadily warming the ocean, which absorbs most of the heat trapped by greenhouse gases in the…
Politics tops science under Trump
Politics Tops Science Under Trump
by Kieran Cooke
If you don’t like the news, then suppress it − because politics tops science in the US today, researchers are finding.
Fossil Fuel Drilling Could Be Contributing To Climate Change By Heating Earth From Within
Fossil Fuel Drilling Could Be Contributing To Climate Change By Heating Earth From Within
by Rizwan Nawaz and Adel Sharif
Almost all scientists agree that burning fossil fuels is contributing to climate change. But agreement is less clear…
A Virtual Reality Field Trip Through South Florida's Everglades
A Virtual Reality Field Trip Through South Florida's Everglades
by Elizabeth (Liz) Miller
Before cities there were swamps. Wetlands and swamps globally have been sacrificed to pave the way for housing,…