Ice sheet collapse triggered ancient sea level peak: ANU media release

Dr. Gianluca Marino and Dr. Katharine Grant load a sediment core into an X-ray fluorescence scanner. Credit: Stuart Hay, ANU

An international team of scientists has found a dramatic ice sheet collapse at the end of the ice age before last caused widespread climate changes and led to a peak in the sea level well above its present height.

The team found the events 135,000 years ago caused the planet to warm in a different way to the end of the most recent ice age about 20,000 to 10,000 years ago.

The findings will help scientists understand the processes that control Earth's dramatic climate changes, said the leader of the study, Dr Gianluca Marino of The Australian National University (ANU).

“We knew the sea level had overshot its present levels during the last interglacial period, but did not know why. Now we for the first time can explain the processes that caused the sea levels to exceed the present levels,” said Dr Marino, from the ANU Research School of Earth Sciences.

“Ice-age cycles may superficially look similar to one another, but there are important differences in the relationships between melting of continental ice sheets and global climate changes.”

The team, which includes researchers from ANU as well as the Universities of Southampton and Swansea in the UK, has published their findings in Nature.

At the end of an ice age the continental ice sheets, ocean, and atmosphere change rapidly. Scientists have previously only been able to reconstruct in detail the changes at the end of the last ice age.

“We have compared the fluctuations at the end of an earlier ice age, and we found that the patterns were different,” said co-author Professor Eelco Rohling, from both ANU and the University of Southampton.

“At the end of the older ice age, 135,000 years ago, we found that a dramatic collapse of the Northern Hemisphere ice sheets into the North Atlantic Ocean suppressed the ocean circulation and caused cooling in the North Atlantic.”

“North Atlantic cooling was counterbalanced by Southern Ocean warming that then destabilised Antarctic land ice, causing a continuation of melting that eventually drove sea level rise to several meters above the present,” he said.

This is very different from the end of the last ice age, said Dr Marino.

“The northern hemisphere ice-sheet collapse and climate change did not occur at the same time, and that caused much less warming in Antarctica,” he said.

The team used precisely-dated cave records and marine sediments from the Mediterranean region to reconstruct the sequence of changes in all critical climate parameters.

Media Contact

Dr. Gianluca Marino
gianluca.marino@anu.edu.au
61-261-253-241

 @ANUmedia

http://www.anu.edu.au/media 

Media Contact

Dr. Gianluca Marino EurekAlert!

All latest news from the category: Earth Sciences

Earth Sciences (also referred to as Geosciences), which deals with basic issues surrounding our planet, plays a vital role in the area of energy and raw materials supply.

Earth Sciences comprises subjects such as geology, geography, geological informatics, paleontology, mineralogy, petrography, crystallography, geophysics, geodesy, glaciology, cartography, photogrammetry, meteorology and seismology, early-warning systems, earthquake research and polar research.

Back to home

Comments (0)

Write a comment

Newest articles

Lighting up the future

New multidisciplinary research from the University of St Andrews could lead to more efficient televisions, computer screens and lighting. Researchers at the Organic Semiconductor Centre in the School of Physics and…

Researchers crack sugarcane’s complex genetic code

Sweet success: Scientists created a highly accurate reference genome for one of the most important modern crops and found a rare example of how genes confer disease resistance in plants….

Evolution of the most powerful ocean current on Earth

The Antarctic Circumpolar Current plays an important part in global overturning circulation, the exchange of heat and CO2 between the ocean and atmosphere, and the stability of Antarctica’s ice sheets….

Partners & Sponsors