Two Centuries Of Continuous Volcanic Eruption May Have Triggered The End Of The Ice Age

Two Centuries Of Continuous Volcanic Eruption May Have Triggered The End Of The Ice Age The Mt. Takeha volcano in west Antartica rises more than 2,000 metres above the surrounding ice sheet. Wikimedia commons

Around 25,000 years ago, during a period known as the Last Glacial Maximum, ice covered much of the world’s landmasses. Comparatively weaker sunlight, large continental ice sheets, and very low amounts of carbon dioxide in the air created the right conditions for an ice age. During the next 15,000 years the global climate shifted from glacial to warm, interglacial conditions as sunlight strengthened.

But the Southern Hemisphere’s climate changed abruptly roughly 18,000 years ago. Rather than the gradual decline you might expect as Earth’s orbit slowly drew nearer to the Sun, something triggered a widespread and simultaneous abrupt change in climate across many continents.

In research published today in Proceedings of the National Academy of Sciences, an international group of researchers and I discovered that a unique, 192-year series of massive volcanic eruptions coincided exactly with the onset of this period of rapid, widespread Southern Hemisphere climate change.

These abrupt climate changes included the pronounced retreat of glaciers in Patagonia and New Zealand and reduced aridity in southern Australia. Lakes rapidly expanded in the Bolivian Andes, and summertime rain in subtropical Brazil increased. Atmospheric dust, recorded in ocean sediment and Antarctic ice cores, was sharply reduced.

Many of these changes have been attributed to a sudden poleward shift in westerly winds encircling Antarctica. The shifting winds changed ocean circulation and ventilation in the deep ocean, affecting glaciers across the southern hemisphere.

What our research explains for the first time is why the winds suddenly changed, and why there was a simultaneous climate transformation across the whole Southern Hemisphere.

Clues within the ice

Antarctica has always been home to globally significant volcanoes. However, 17,700 years ago a unique event began: nearly continuous volcanic eruptions over 192 years that spewed huge amounts of chemicals known as halogens into the Antarctic atmosphere.

Two Centuries Of Continuous Volcanic Eruption May Have Triggered The End Of The Ice Age A researcher loads 18,000-year-old Antarctic ice for continuous analysis. PNAS, CC BY

These halogens – including powerful ozone destroyers bromine, chloride and iodine – created a hole in the ozone layer, which was in many ways similar to the modern hole triggered by humans’ use of halogen-containing compounds called CFCs. This led to large-scale changes in atmospheric circulation and initiated the shift away from a glacial climate state.

These findings are based on detailed chemical measurements of a broad range of elements and chemical traces in Antarctic ice cores. Most of these came from the West Antarctic Ice Sheet Divide (WAIS), a 3,405 metre deep drilling site that provides highly precise climate records over the past 68,000 years.

Our research included the broadest suite of chemical and elemental analysis ever attempted on a deep ice core, and the most precise breakdown of time. This record of the eruptions was precisely duplicated in replicate samples from the same ice core, and in ice cores taken from near Byrd Station in West Antarctica, and Taylor Glacier in Antartica’s Dry Valleys.

The ice core records showed a very unusual, 192-year chemical anomaly from 17,748 to 17,556 years before present.

We augmented the high resolution ice core analyses with a host of lower resolution measurements of interplanetary dust, rock fragments ejected during volcanic eruptions, and sulphur isotopes. Together, they clearly showed the chemical anomaly was the result of a series of massive volcanic eruptions from Mt Takahe, about 350km north of our main drill site.

Other characteristics of the chemical record – including anomalies in sulfur isotopes and near complete bromine depletion in the ice during the event – were consistent with increased ultraviolet radiation at Earth’s surface. It suggests that halogens (chlorine, bromine, and iodine) and other material from the Mt Takahe eruptions reached the Antarctic stratosphere where they destroyed ozone.

Two Centuries Of Continuous Volcanic Eruption May Have Triggered The End Of The Ice Age The massive, halogen-rich eruptions of Mt. Takahe coincided with the onset of abrupt and widespread climate change in the southern hemisphere, and increasing greenhouse gas concentrations during the end of the last ice age. Author provided

These eruptions and their chemical signature are unique in the 68,000-year WAIS Divide record. Fallout containing elevated levels of hydrofluoric and hydrochloric acid, as well as toxic heavy metals, extended at least 2,800km from Mt Takahe and may have reached southern South America.

Correlation vs causation

The Southern Hemisphere’s glaciers took 10,000 years to fully retreat. But these unique volcanic eruptions occurred just before (or possibly during) the most significant period of rapid climate change in the Southern Hemisphere, and global greenhouse gas concentrations increased during this time.

The fundamental question is: “did these two events occur at the same time by coincidence or were they causally linked?” The probability that these two events coincided simply by chance is negligible. Based on the evidence we found in Antartica’s ice cores, the depletion of the ozone layer may be the crucial linking factor.

We can bolster this link by comparing the climate change of 17,700 years ago to observable climate change today attributed to the modern Antarctic ozone hole. We can also look to climate models that simulate the behaviour of an ozone hole under glacial conditions. Overall, the widespread climate change observed in many paleoclimate records can best be explained by this singular and dramatic event in western Antarctica.The Conversation

About The Author

Joe McConnell, Research Professor, and Director of the Ultra-Trace Chemistry Laboratory, Desert Research Institute

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.

 

follow InnerSelf on

facebook icontwitter iconyoutube iconinstagram iconpintrest iconrss icon

 Get The Latest By Email

Weekly Magazine Daily Inspiration

EVIDENCE

Blue water surrounded by dead white grass
Map tracks 30 years of extreme snowmelt across US
by Mikayla Mace-Arizona
A new map of extreme snowmelt events over the last 30 years clarifies the processes that drive rapid melting.
White sea ice in blue water with the sun setting reflected in the water
Earth’s frozen areas are shrinking 33K square miles a year
by Texas A&M University
The Earth’s cryosphere is shrinking by 33,000 square miles (87,000 square kilometers) per year.
wind turbines
A controversial US book is feeding climate denial in Australia. Its central claim is true, yet irrelevant
by Ian Lowe, Emeritus Professor, School of Science, Griffith University
My heart sank last week to see conservative Australian commentator Alan Jones championing a contentious book about…
image
Reuters' Hot List of climate scientists is geographically skewed: why this matters
by Nina Hunter, Post-Doctoral Researcher, University of KwaZulu-Natal
The Reuters Hot List of “the world’s top climate scientists” is causing a buzz in the climate change community. Reuters…
A person holds a shell in their hand in blue water
Ancient shells hint past high CO2 levels could return
by Leslie Lee-Texas A&M
Using two methods to analyze tiny organisms found in sediment cores from the deep seafloor, researchers have estimated…
image
Matt Canavan suggested the cold snap means global warming isn't real. We bust this and 2 other climate myths
by Nerilie Abram, Professor; ARC Future Fellow; Chief Investigator for the ARC Centre of Excellence for Climate Extremes; Deputy Director for the Australian Centre for Excellence in Antarctic Science, Australian National University
Senator Matt Canavan sent many eyeballs rolling yesterday when he tweeted photos of snowy scenes in regional New South…
Ecosystem sentinels sound alarm for the oceans
by Tim Radford
Sea birds are known as ecosystem sentinels, warning of marine loss. As their numbers fall, so could the riches of the…
Why Sea Otters Are Climate Warriors
Why Sea Otters Are Climate Warriors
by Zak Smith
In addition to being one of the cutest animals on the planet, sea otters help maintain healthy, carbon-absorbing kelp…

LATEST VIDEOS

The Great Climate Migration Has Begun
The Great Climate Migration Has Begun
by Super User
The climate crisis is forcing thousands around the world to flee as their homes become increasingly uninhabitable.
The Last Ice Age Tells Us Why We Need To Care About A 2℃ Change In Temperature
The Last Ice Age Tells Us Why We Need To Care About A 2℃ Change In Temperature
by Alan N Williams, et al
The latest report from the Intergovernmental Panel on Climate Change (IPCC) states that without a substantial decrease…
Earth Has Stayed Habitable For Billions Of Years – Exactly How Lucky Did We Get?
Earth Has Stayed Habitable For Billions Of Years – Exactly How Lucky Did We Get?
by Toby Tyrrell
It took evolution 3 or 4 billion years to produce Homo sapiens. If the climate had completely failed just once in that…
How Mapping The Weather 12,000 Years Ago Can Help Predict Future Climate Change
How Mapping The Weather 12,000 Years Ago Can Help Predict Future Climate Change
by Brice Rea
The end of the last ice age, around 12,000 years ago, was characterised by a final cold phase called the Younger Dryas.…
The Caspian Sea Is Set To Fall By 9 Metres Or More This Century
The Caspian Sea Is Set To Fall By 9 Metres Or More This Century
by Frank Wesselingh and Matteo Lattuada
Imagine you are on the coast, looking out to sea. In front of you lies 100 metres of barren sand that looks like a…
Venus Was Once More Earth-like, But Climate Change Made It Uninhabitable
Venus Was Once More Earth-like, But Climate Change Made It Uninhabitable
by Richard Ernst
We can learn a lot about climate change from Venus, our sister planet. Venus currently has a surface temperature of…
Five Climate Disbeliefs: A Crash Course In Climate Misinformation
The Five Climate Disbeliefs: A Crash Course In Climate Misinformation
by John Cook
This video is a crash course in climate misinformation, summarizing the key arguments used to cast doubt on the reality…
The Arctic Hasn't Been This Warm For 3 Million Years and That Means Big Changes For The Planet
The Arctic Hasn't Been This Warm For 3 Million Years and That Means Big Changes For The Planet
by Julie Brigham-Grette and Steve Petsch
Every year, sea ice cover in the Arctic Ocean shrinks to a low point in mid-September. This year it measures just 1.44…

LATEST ARTICLES

trees to plant for climate2
Plant These Trees To Improve City Life
by Mike Williams-Rice
A new study establishes live oaks and American sycamores as champions among 17 “super trees” that will help make cities…
north sea sea bed
Why We Must Understand Seabed Geology To Harness The Winds
by Natasha Barlow, Associate Professor of Quaternary Environmental Change, University of Leeds
For any country blessed with easy access to the shallow and windy North Sea, offshore wind will be key to meeting net…
3 wildfire lessons for forest towns as Dixie Fire destroys historic Greenville, California
3 wildfire lessons for forest towns as Dixie Fire destroys historic Greenville, California
by Bart Johnson, Professor of Landscape Architecture, University of Oregon
A wildfire burning in hot, dry mountain forest swept through the Gold Rush town of Greenville, California, on Aug. 4,…
China Can Meet Energy and Climate Goals Capping Coal Power
China Can Meet Energy and Climate Goals Capping Coal Power
by Alvin Lin
At the Leader’s Climate Summit in April, Xi Jinping pledged that China will “strictly control coal-fired power…
Blue water surrounded by dead white grass
Map tracks 30 years of extreme snowmelt across US
by Mikayla Mace-Arizona
A new map of extreme snowmelt events over the last 30 years clarifies the processes that drive rapid melting.
A plane drops red fire retardant on to a forest fire as firefighters parked along a road look up into the orange sky
Model predicts 10-year burst of wildfire, then gradual decline
by Hannah Hickey-U. Washington
A look at the long-term future of wildfires predicts an initial roughly decade-long burst of wildfire activity,…
White sea ice in blue water with the sun setting reflected in the water
Earth’s frozen areas are shrinking 33K square miles a year
by Texas A&M University
The Earth’s cryosphere is shrinking by 33,000 square miles (87,000 square kilometers) per year.
A row of male and female speakers at microphones
234 scientists read 14,000+ research papers to write the upcoming IPCC climate report
by Stephanie Spera, Assistant Professor of Geography and the Environment, University of Richmond
This week, hundreds of scientists from around the world are finalizing a report that assesses the state of the global…

 Get The Latest By Email

Weekly Magazine Daily Inspiration

New Attitudes - New Possibilities

InnerSelf.comClimateImpactNews.com | InnerPower.net
MightyNatural.com | WholisticPolitics.com | InnerSelf Market
Copyright ©1985 - 2021 InnerSelf Publications. All Rights Reserved.