The current warming trends in the Arctic may shove the Arctic system into a seasonally ice-free state not seen for more than one million years, according to a new report. The melting is accelerating, and a team of researchers was unable to identify any natural processes that might slow the de-icing of the Arctic.
Such substantial additional melting of Arctic glaciers and ice sheets will raise sea level worldwide, flooding the coastal areas where many of the worlds people live. Melting sea ice has already resulted in dramatic impacts for the indigenous people and animals in the Arctic, which includes parts of Alaska, Canada, Russia, Scandinavia, and Greenland.
The report is the result of week-long meeting of an interdisciplinary team of scientists that examined how the Arctic environment and climate interact and how that system would respond as global temperatures rise. It was organized by the National Science Foundations Arctic System Science Committee, which is chaired by Jonathan T. Overpeck of the University of Arizona. The report by Overpeck, who also chaired the meeting, and 20 colleagues from the United States and Canada is published 23 August in Eos, the weekly newspaper of the American Geophysical Union.
"What really makes the Arctic different from the rest of the non-polar world is the permanent ice in the ground, in the ocean, and on land," said Overpeck "We see all of that ice melting already, and we envision that it will melt back much more dramatically in the future, as we move towards this more permanent ice-free state."
The past climates in the Arctic include glacial periods, where sea ice coverage expanded and ice sheets extended into Northern America and Europe, and warmer interglacial periods during which the ice retreats, such as the past 10,000 years. By studying natural data loggers such as ice cores and marine sediments, scientists have a good idea what the "natural envelope" for Arctic climate variations has been for the past million years, Overpeck said.
At the workshop, the team of scientists synthesized what is currently known about the Arctic and defined key components that make up the current system. They identified how the components interact, including feedback loops that involve multiple parts of the system. "In the past, researchers have tended to look at individual components of the Arctic," said Overpeck. "What we did for the first time is really look at how all of those components work together."
The team concluded that there were two major amplifying feedbacks in the Arctic system, involving the interplay between sea and land ice, ocean circulation in the North Atlantic, and the amounts of precipitation and evaporation in the system. Such feedback loops accelerate changes in the system, Overpeck explained. For example, the white surface of sea ice reflects radiation from the Sun. As sea ice melts, more solar radiation is absorbed by the dark ocean, which heats up and results in yet more sea ice melting.
The scientists identified one feedback loop that could slow the changes, but they did not see any natural mechanism that could stop the dramatic loss of ice. "I think probably the biggest surprise of the meeting was that no one could envision any interaction between the components that would act naturally to stop the trajectory to the new system," Overpeck said, adding that the group investigated several possible braking mechanisms that had been previously suggested.
In addition to sea and land ice melting, Overpeck warned that permafrost, the permanently frozen layer of soil that underlies much of the Arctic landmass, will melt and eventually disappear in some areas. Such thawing could release additional greenhouse gases stored in the permafrost for thousands of years, which would amplify human-induced climate change.
Harvey Leifert | American Geophysical Union
New insights into the ancestors of all complex life
29.05.2017 | University of Bristol
A 3-D look at the 2015 El Niño
29.05.2017 | NASA/Goddard Space Flight Center
The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.
The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
29.05.2017 | Earth Sciences
29.05.2017 | Life Sciences
29.05.2017 | Physics and Astronomy