Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Baffin Island ice caps shrink by 50 percent since 1950s

30.01.2008
Researchers also find tantalizing evidence that ancient tropical eruptions of volcanoes triggered Little Ice Age

A new University of Colorado at Boulder study has shown that ice caps on the northern plateau of Baffin Island in the Canadian Arctic have shrunk by more than 50 percent in the last half century as a result of warming, and are expected to disappear by the middle of the century.

Radiocarbon dating of dead plant material emerging from beneath the receding ice margins show the Baffin Island ice caps are now smaller in area than at any time in at least the last 1,600 years, said geological sciences Professor Gifford Miller of CU-Boulder's Institute of Arctic and Alpine Research. "Even with no additional warming, our study indicates these ice caps will be gone in 50 years or less," he said.

The study also showed two distinct bursts of Baffin Island ice-cap growth commencing about 1280 A.D. and 1450 A.D., each coinciding with ice-core records of increases in stratospheric aerosols tied to major tropical volcanic eruptions, Miller said. The unexpected findings "provide tantalizing evidence that the eruptions were the trigger for the Little Ice Age," a period of Northern Hemisphere cooling that lasted from roughly 1250 to 1850, he said.

A paper on the subject was published online in Geophysical Research Letters and featured in the Jan. 28 edition of the American Geophysical Union journal highlights. Authors on the study included Miller, graduate students Rebecca Anderson and Stephen DeVogel of INSTAAR, Jason Briner of the State University of New York at Buffalo and Nathaniel Lifton of the University of Arizona.

Located just west of Greenland, the 196,000 square-mile Baffin Island is the fifth largest island in the world. Most of it lies above the Arctic Circle.

The researchers also used satellite data and aerial photos beginning in 1949 to document the shrinkage of more than 20 ice caps on the northern plateau of Baffin Island, which are up to 4 miles long, generally less than 100 yards thick and frozen to their beds. "The ice is so cold and thin that it doesn't flow, so the ancient landscape on which they formed is preserved pretty much intact," said Miller.

In addition to carbon-dating plant material from the ice edges, the researchers extracted and analyzed carbon 14 that formed inside the Baffin Island rocks as a result of ongoing cosmic radiation bombardment, revealing the amount of time the rocks have been exposed, he said. The analysis of carbon 14 in quartz crystals indicated that for several thousand years prior to the last century, there had been more ice cover on Baffin Island, Miller said.

The increase of ice extent across the Arctic in recent millennia is thought to be due in large part to decreasing summer solar radiation there as a result of a long-term, cyclic wobble in Earth's axis, said Miller. "This makes the recent ice-cap reduction on Baffin Island even more striking," he said.

Funded primarily by the National Science Foundation, the study is among the first to use radiocarbon samples from rocks for dating purposes, Miller said. The radiocarbon portion of the study was conducted at INSTAAR and the University of Arizona.

Temperatures across the Arctic have been rising substantially in recent decades as a result of the build up of greenhouse gases in Earth's atmosphere. Studies by CU-Boulder researchers in Greenland indicate temperatures on the ice sheet have climbed 7 degrees Fahrenheit since 1991.

Gifford Mller | EurekAlert!
Further information:
http://www.colorado.edu

More articles from Earth Sciences:

nachricht In times of climate change: What a lake’s colour can tell about its condition
21.09.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht Did marine sponges trigger the ‘Cambrian explosion’ through ‘ecosystem engineering’?
21.09.2017 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>