About 15,000 years ago, the ocean around Antarctica has seen an abrupt sea level rise of several meters. It could happen again. An international team of scientists with the participation of the University of Bonn is now reporting its findings in the magazine Nature Scientific Reports.
University of Bonn’s climate researcher Michael E. Weber is a member of the study group. He says, "The changes that are currently taking place in a disturbing manner resemble those 14,700 years ago."
At that time, changes in atmospheric-oceanic circulation led to a stratification in the ocean with a cold layer at the surface and a warm layer below. Under such conditions, ice sheets melt more strongly than when the surrounding ocean is thoroughly mixed. This is exactly what is presently happening around the Antarctic.
The main author of the study, the Australian climate researcher Chris Fogwill from the Climate Change Research Center in Sydney, explains the process as follows: "The reason for the layering is that global warming in parts of Antarctica is causing land based ice to melt, adding massive amounts of freshwater to the ocean surface.
At the same time as the surface is cooling, the deeper ocean is warming, which has already accelerated the decline of glaciers in the Amundsen Sea Embayment.” It appears global warming is replicating conditions that, in the past, triggered significant shifts in the stability of the Antarctic ice sheet.
To investigate the climate changes of the past, the scientists are studying drill cores from the eternal ice. Layer by layer, this frozen "climate archive" reveals its secrets to the experts. In previous studies, the scientists had found evidence of eight massive melting events in deep sea sediments around the Antarctic, which occurred at the transition from the last ice age to the present warm period.
Co-author Dr. Weber from the Steinmann Institute of the University of Bonn says: "The largest melt occurred 14,700 years ago. During this time the Antarctic contributed to a sea level rise of at least three meters within a few centuries."
The present discovery is the first direct evidence from the Antarctic continent which confirms the assumed models. The research team used isotopic analyzes of ice cores from the Weddell Sea region, which now flows into the ocean about a quarter of the Antarctic melt.
Through a combination with ice sheet and climate modeling, the isotopic data show that the waters around the Antarctic were heavily layered at the time of the melting events, so that the ice sheets melted at a faster rate. "The big question is whether the ice sheet will react to these changing ocean conditions as rapidly as it did 14,700 years ago," says co-author Nick Golledge from the Antarctic Research Center in Wellington, New Zealand.
Publication: Antarctic ice shield discharge driven by atmosphere-ocean feedbacks at the Last Glacial Termination, DOI: 10.1038/srep39979
Contact for the media:
Dr. Michael Weber
Universitäty of Bonn
Tel. +49 (0)160 / 96635405
Dr. Andreas Archut | idw - Informationsdienst Wissenschaft
Filling the gap: High-latitude volcanic eruptions also have global impact
20.11.2017 | Institute of Atmospheric Physics, Chinese Academy of Sciences
Antarctic landscape insights keep ice loss forecasts on the radar
20.11.2017 | University of Edinburgh
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
21.11.2017 | Physics and Astronomy
21.11.2017 | Physics and Astronomy
21.11.2017 | Life Sciences