Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

'Ice age blob' of warm ocean water discovered south of Greenland

22.02.2016

New research published in Scientific Reports in February indicates that a warm ocean surface water prevailed during the last ice age, sandwiched between two major ice sheets just south of Greenland.

Extreme climate changes in the past Ice core records show that Greenland went through 25 extreme and abrupt climate changes during the last ice age some 20.000 to 70.000 years ago. In less than 50 years the air temperatures over Greenland could increase by 10 to 15 °C.


Greenland experienced several abrupt and brutal climate changes during the last ice age. But even during the coldest periods a blob of warm surface water existed nearby.

Credit: M. Sojtaric/CAGE/colourbox.com

However the warm periods were short; within a few centuries the frigid temperatures of the ice age returned. That kind of climate change would have been catastrophic for us today. (link)

Ice core records from Antarctica also show climate changes in the same period, but they are more gradual, with less severe temperature swings.

The Nature Scientific Report study shows that an area of the Nordic Seas, just south of Iceland, followed the Antarctic pattern of warming and cooling. Which is strange since it is so close to Greenland.

"We had expected to see sudden climate changes. But sediment core records from the area show that the climate changes here were actually gradual, and quite identical to Antarctic climate changes." says CAGE professor Tine Rasmussen, the principal author of the paper.

Gulf Stream holds the answers

Then, as now, the circulation of Atlantic Ocean, with currents such as the Gulf Stream, regulated transportation of heat to this area. Simply put, the surface currents transport heat from the southern and tropical Atlantic toward the North Atlantic.

" The Nordic seas between Norway and Greenland play a crucial role for the current patterns of the Atlantic Ocean. They act as a pump. Here the warm and salty surface water cools down during winter. It becomes heavy and is pumped down to the bottom before returning to the Atlantic, where it continues as a deep current all the way to the Antarctic region. " co-author Erik Thomsen from Aarhus University ( link) points out.

Without this pump, the north-south current system would slow down considerably. Changes in this circulation can have a profound impact on the global climate system.

During the ice ages this circulation was assumed to work as a seesaw in the playground - going up and down in opposite directions with an axis somewhere around the equator. The idea is that when it warmed in the north, it cooled in the south and vice versa. But Rasmussen and colleagues indicate another scenario.

Rewriting the seesaw hypothesis

During the coldest periods of the last ice age the Nordic seas were covered with a permanent layer of sea ice. The pump stopped transporting the heat northward. The heat accumulated in the southern oceans. However, the warming was not restricted to the south.

" Our results show that it continued all the way to Iceland. The warming was slow and gradual, and happened simultaneously in both hemispheres. Little by little the warm Atlantic water penetrated into the Nordic sea underneath the ice cover. It melted the ice from below. Once the ice was gone, the pump started up again, bringing additional warm water into the Nordic seas. And we got a warmer period for 50 years. " says Rasmussen.

Large ice sheets continued however, to cover the continents around the Nordic seas. In contact with the warm ocean water they started calving. This delivered icebergs and fresh water into the sea and caused a cooling down of the surface water. The seas were again frozen. And the pump slowed down.

The warm ocean blob of the ice ages rewrites the understanding of the ocean circulation systems, and how they affected the extreme climate changes of the past. The seesaw was actually more of a 'push and pull' system.

"There are no symmetrical processes in the north and the south - the climate changes were principally governed by simultaneous warming and the constant closing and re-opening of the sink pump in the Nordic seas" says Tine Rasmussen.

Media Contact

Maja Sojtaric
maja.sojtaric@uit.no
479-184-5151

 @CAGE_COE

Maja Sojtaric | EurekAlert!

Further reports about: Antarctic CAGE Gulf Stream Hydrate climate changes ice age ocean water pump

More articles from Earth Sciences:

nachricht New sensor could shake up earthquake response efforts
11.07.2019 | DOE/Lawrence Berkeley National Laboratory

nachricht NASA satellites find biggest seaweed bloom in the world
09.07.2019 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Megakaryocytes act as „bouncers“ restraining cell migration in the bone marrow

Scientists at the University Würzburg and University Hospital of Würzburg found that megakaryocytes act as “bouncers” and thus modulate bone marrow niche properties and cell migration dynamics. The study was published in July in the Journal “Haematologica”.

Hematopoiesis is the process of forming blood cells, which occurs predominantly in the bone marrow. The bone marrow produces all types of blood cells: red...

Im Focus: Artificial neural network resolves puzzles from condensed matter physics: Which is the perfect quantum theory?

For some phenomena in quantum many-body physics several competing theories exist. But which of them describes a quantum phenomenon best? A team of researchers from the Technical University of Munich (TUM) and Harvard University in the United States has now successfully deployed artificial neural networks for image analysis of quantum systems.

Is that a dog or a cat? Such a classification is a prime example of machine learning: artificial neural networks can be trained to analyze images by looking...

Im Focus: Extremely hard yet metallically conductive: Bayreuth researchers develop novel material with high-tech prospects

An international research group led by scientists from the University of Bayreuth has produced a previously unknown material: Rhenium nitride pernitride. Thanks to combining properties that were previously considered incompatible, it looks set to become highly attractive for technological applications. Indeed, it is a super-hard metallic conductor that can withstand extremely high pressures like a diamond. A process now developed in Bayreuth opens up the possibility of producing rhenium nitride pernitride and other technologically interesting materials in sufficiently large quantity for their properties characterisation. The new findings are presented in "Nature Communications".

The possibility of finding a compound that was metallically conductive, super-hard, and ultra-incompressible was long considered unlikely in science. It was...

Im Focus: Modelling leads to the optimum size for platinum fuel cell catalysts: Activity of fuel cell catalysts doubled

An interdisciplinary research team at the Technical University of Munich (TUM) has built platinum nanoparticles for catalysis in fuel cells: The new size-optimized catalysts are twice as good as the best process commercially available today.

Fuel cells may well replace batteries as the power source for electric cars. They consume hydrogen, a gas which could be produced for example using surplus...

Im Focus: The secret of mushroom colors

Mushrooms: Darker fruiting bodies in cold climates

The fly agaric with its red hat is perhaps the most evocative of the diverse and variously colored mushroom species. Hitherto, the purpose of these colors was...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on UV LED Technologies & Applications – ICULTA 2020 | Call for Abstracts

24.06.2019 | Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

 
Latest News

Flying Laptop satellite mission extended by two years - Successfully in orbit since July 14, 2017

16.07.2019 | Physics and Astronomy

New safer, inexpensive way to propel small satellites

16.07.2019 | Power and Electrical Engineering

UCI electrical engineering team develops 'beyond 5G' wireless transceiver

16.07.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>