About the same time, a sharp century long cold spell is observed around the North Atlantic and other areas. Researchers have often speculated that the cooling was the result of changes in ocean circulation triggered by this freshwater flood. The sudden addition of so much freshwater would have curtailed (suppressed) the sinking of deep water in the North Atlantic and as a consequence less warm water would be pulled north in the Gulf stream.
In a new study in Science (published online in Science Express 6 December) Kleiven and co workers confirm that the deep ocean was disturbed in just the way previous workers had speculated. Using a marine core from south of Greenland, which monitors the southward flowing deep waters formed in the North Atlantic they show that there is a sudden disruption in the deep circulation pattern at the time of the flood outburst. Just at the time of the flood, the chemical properties of the deep ocean shift suddenly to values not observed at any other time in the last 10,000 years. The chemical changes suggest that at the site south of Greenland, the new deep waters formed in the North were completely replaced by older deepwater coming from the south. This suggests that deep waters from the North Atlantic were too shallow or weak to influence this site for about century following the flood outburst after which time the deep ocean snapped back to its near modern state. This is what researchers had predicted and what computers have simulated the ocean needed to have done in order to help bring about the cold spell.
Kleiven et al., strengthen the connection between the deep ocean changes and the climate anomaly by showing that the sharp cooling at their location falls within the century long disruption in deep circulation. If the cooling had fallen outside the period of disrupted circulation, the role of the ocean and related heat transport could have been ruled out as the major driver of the cooling. Perhaps even more importantly, they show that deep circulation is altered over just a few decades or less demonstrating that the the deep ocean changes fast enough to drive the sudden jump in climate seen at this and other times in the past.
There is no modern or future equivalent source for freshwater to cause a mega flood like that which occurred 8400 years ago. Yet, the fact that these deep ocean changes clearly occur on timescales rapidly enough to impact human societies underscores the importance of determining just how much freshwater is needed to bring about such dramatic changes—given the concerns that melting of the Greenland Ice Sheet may accelerate as the globe warms.
Helga Kleiven | alfa
Climate change weakens Walker circulation
20.10.2017 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen
Shallow soils promote savannas in South America
20.10.2017 | Senckenberg Forschungsinstitut und Naturmuseen
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research