|
New glacier history sheds light on climate change
By Phoebe Dey, ExpressNews Staff
University of Alberta news release
January 9, 2006
University of Alberta research that rewrites the history of glacial movement in northwestern North America over the past 10,000 years offers important clues to climate change in recent millennia.
Glacier fluctuations are sensitive indicators of past climate change, yet little is known about glacier activity in Pacific North America during the first millennium A.D. Alberto Reyes, a PhD student in the Department of Earth and Atmospheric Sciences, and his research team have found evidence for a regionally extensive glacier expansion during that time, suggesting that climate during the last several thousand years may have been more variable than previously thought. The research appears in the journal Geology.
Reyes and his collaborators - mainly Dr. Dan Smith from the University of Victoria and Dr. Greg Wiles from the College of Wooster in Ohio - looked for a variety of clues in the field to help figure out the timing of past glacier fluctuations. At almost all of the glaciers studied, surface evidence prior to the "Little Ice Age" had been destroyed because glacial advance during that time had been so dramatic. Most of the evidence they found was in the form of buried soils and logs covered by glacial sediments.
"In some cases, entire forest stands were buried by sediments, and their trunks sheared off by advancing ice," said Reyes, who initiated the work while a master's student at Simon Fraser University.
|
Related articles
Alaska's Columbia Glacier shrunk by 9 miles since 1980
Alaska's rapidly disintegrating Columbia Glacier, which has shrunk in length by 9 miles since 1980, has reached the mid-point of its projected retreat, according to a new University of Colorado at Boulder study.
Global warming will reduce glaciers, water supply and affect millions of people
In the looming future, global warming will reduce glaciers and storage packs of snow in regions around the world, causing water shortages and other problems that will impact millions of people. That is the conclusion of researchers at Scripps Institution of Oceanography at the University of California , San Diego, and the University of Washington in a review paper published in the November 17 issue of the journal Nature.
75% of Switzerland's glaciers gone by 2050, Europe heats up
The four hottest years on record were 1998, 2002, 2003 and 2004. Ten percent of Alpine glaciers disappeared during the summer of 2003 alone. At current rates, three quarters of Switzerland's glaciers will have melted by 2050. Europe has not seen climate changes on this scale for 5 000 years, says a new report by the European Environment Agency (EEA), based in Copenhagen.
Carbon in Canada's boreal forest worth $3.7 trillion
Carbon stored in Canada's boreal forests and peatlands is worth $3.7 trillion according to research by the Pembina Institute for the Canadian Boreal Initiative (CBI). The two-year study puts the value of ecosystem services like water filtration, pest-control services, and carbon storage at $93 billion -- roughly 2.5 times greater than the net market value of forestry, hydroelectric, mining, and oil and gas extraction in Canada's Boreal region.
|
Samples were then sent off for radiocarbon dating, and when the results came back, the researchers were able to determine when each individual glacier was expanding. Reyes had earlier noted a first-millennium-AD advance at the glacier he was studying for his master's thesis, which jumped out because it was thought glaciers in the region weren't expanding at that time.
After poring over old data and early results of new research, the team found that many other glaciers had also advanced during that period. "If only one or two glaciers are advancing at any particular time, it is not really significant," said Reyes. "But when many glaciers across a wide region are advancing with some degree of synchronicity, there is likely something going on with regional climate that causes the glaciers to advance."
Reyes was surprised that the regional nature of this first-millennium-AD glacier advance remained unrecognized for so long. He suspects that earlier reports hinting at the existence of an advance slipped under the radar because they did not fit into the established chronology of past glacier activity.
The glacier data reported by Reyes and colleagues, together with other clues of past climate, support an emerging idea that climate in the North Pacific region has cycled from warmer to colder intervals several times over the last 10,000 years.
This is a modified news release from the Earth University of Alberta.
News index | RSS | Add to MyYahoo!
Advertisements:
Organic Apparel from Patagonia | Insect-repelling clothing
| |
|
MONGABAY.COM
Mongabay.com seeks to raise interest in and appreciation of wild lands and wildlife, while examining the impact of emerging trends in climate, technology, economics, and finance on conservation and development (more)
CONTENTS
POPULAR PAGES
T-SHIRTS
Madagascar Wildlife
Dancing lemurs
Don't fall asleep the sloths will eat you
Sucking on this frog may make you insane
CALENDARS
Mount Kenya
East Africa Safari Wildlife
Kenya's Turkana People
Peru
African Wildlife
Alaska
China
Madagascar Chameleons
CANVAS BAGS
Hallucinogenic frog bag
Madagascar wildlife bag
|
|
