Mark Serreze, a senior research scientist at CU-Boulder's National Snow and Ice Data Center who led the study synthesizing results from recent research, said the Arctic sea-ice extent trend has been negative in every month since 1979, when concerted satellite record keeping efforts began. The team attributed the loss of ice, about 38,000 square miles annually as measured each September, to rising concentrations of greenhouse gases and strong natural variability in Arctic sea ice.
"When the ice thins to a vulnerable state, the bottom will drop out and we may quickly move into a new, seasonally ice-free state of the Arctic," Serreze said. "I think there is some evidence that we may have reached that tipping point, and the impacts will not be confined to the Arctic region."
A review paper by Serreze and Julienne Stroeve of CU-Boulder's NSIDC and Marika Holland of the National Center for Atmospheric Research titled "Perspectives on the Arctic's Shrinking Sea Ice Cover" appears in the March 16 issue of Science.
The loss of Arctic sea ice is most often tied to negative effects on wildlife like polar bears and increasing erosion of coastlines in Alaska and Siberia, he said. But other studies have linked Arctic sea ice loss to changes in atmospheric patterns that cause reduced rainfall in the American West or increased precipitation over western and southern Europe, he said.
The decline in Arctic sea ice could impact western states like Colorado, for example, by reducing the severity of Arctic cold fronts dropping into the West and reducing snowfall, impacting the ski industry and agriculture, he said. "Just how things will pan out is unclear, but the bottom line is that Arctic sea ice matters globally," Serreze said.
Because temperatures across the Arctic have risen from 2 degrees to 7 degrees F. in recent decades due to a build-up of atmospheric greenhouse gases, there is no end in sight to the decline in Arctic sea ice extent, said Serreze of CU-Boulder's Cooperative Institute for Research in Environmental Sciences. Arctic sea ice extent is defined as the total area of all regions where ice covers at least 15 percent of the ocean surface.
"While the Arctic is losing a great deal of ice in the summer months, it now seems that it also is regenerating less ice in the winter," said Serreze. "With this increasing vulnerability, a kick to the system just from natural climate fluctuations could send it into a tailspin."
In the late 1980s and early 1990s, shifting wind patterns from the North Atlantic Oscillation flushed much of the thick sea ice out of the Arctic Ocean and into the North Atlantic where it drifted south and eventually melted, he said. The thinner layer of "young" ice that formed it its place melts out more readily in the succeeding summers, leading to more open water and more solar radiation being absorbed by the open ocean and fostering a cycle of higher temperatures and earlier ice melt, he said.
"This ice-flushing event could be a small-scale analog of the sort of kick that could invoke rapid collapse, or it could have been the kick itself," he said. "At this point, I don't think we really know."
Researchers also have seen pulses of warmer water from the North Atlantic entering the Arctic Ocean beginning in the mid-1990s, which promote ice melt and discourage ice growth along the Atlantic ice margin, he said. "This is another one of those potential kicks to the system that could evoke rapid ice decline and send the Arctic into a new state."
The potential for such rapid ice loss was highlighted in a December 2006 study by Holland and her colleagues published in Geophysical Research Letters. In one of their climate model simulations, the Arctic Ocean in September became nearly ice-free between 2040 and 2050.
"Given the growing agreement between models and observations, a transition to a seasonally ice-free Arctic Ocean as the system warms seems increasingly certain," the researchers wrote in Science. "The unresolved questions regard when this new Arctic state will be realized, how rapid the transition will be, and what will be the impacts of this new state on the Arctic and the rest of the globe."
Mark Serreze | EurekAlert!
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
Scientists have developed a new method of characterizing graphene’s properties without applying disruptive electrical contacts, allowing them to investigate both the resistance and quantum capacitance of graphene and other two-dimensional materials. Researchers from the Swiss Nanoscience Institute and the University of Basel’s Department of Physics reported their findings in the journal Physical Review Applied.
Graphene consists of a single layer of carbon atoms. It is transparent, harder than diamond and stronger than steel, yet flexible, and a significantly better...
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...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
30.05.2017 | Life Sciences
30.05.2017 | Life Sciences
30.05.2017 | Physics and Astronomy