Deep ocean sediments offer a record of ocean circulation in the past. By studying these sediments, we can see that abrupt changes in ocean circulation and the subsequent climate change are not a new phenomenon, but have happened on several occasions in the past. When the great ice sheets covering North America and Scandinavia melted at the end of the last ice age, the subsequent flow of fresh water into the North Atlantic caused the greatest natural disturbance in ocean circulation in the last 20,000 years. This episode provides an excellent model to examine the relation between ocean disturbance and climate instability.
According to a revision article published in Science, ocean circulation during the last ice age was very different to present day circulation. The formation of deep water currents in the North Atlantic was much weaker and the flow of warm water from the Gulf Stream decreased. This led to a cooling of the northern hemisphere and contributed to the formation of the great ice caps which covered North America, Scandinavia and Europe.
In a similar study, the marine sediments of the North Atlantic were observed in order to document the sequence of events that led to that disturbance. The melting caused a significant decrease in the Gulf Stream, which transports warm water from the Gulf of Mexico to the North. This submerged the region of the North Atlantic into a period of glacial cold which lasted at least 1,200 years.
Nevertheless, the slowing down of the ocean circulation in the North Atlantic began about 700 to 1,200 years before this great melting of the ice caps and the subsequent flow of fresh water into the ocean took place. The very first stage of this change coincided with brief and isolated periods of melting of the small British Ice Sheet (BIS). The authors of the study have come to this conclusion from an observation of the fine layers of sediment (formed by grains of quartz) coming from successive waves of icebergs which, when they melted dumped their load of sediments onto the sea bed. These icebergs came from the edges of the ice which surround and stabilised the BIS.
These results show that the disturbances caused by melting may in turn cause substantial changes in ocean circulation without the need for a catastrophic dumping of fresh water. This seems to indicate that an acceleration in the melting of the Greenland ice cap, could, in fact, play a key role in the future stability of ocean circulation and climate change in the whole North Atlantic region.
Octavi López Coronado | alfa
New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg
Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences