Saturday, April 06, 2013 3:53:37 AM
A New "Rosetta Stone" Tropical Ice Core
The Quelccaya ice cap, 12 kilometers across, is the largest icefield in South America.
Google Maps image
by Andrew Alden
Apr 04, 2013
When it comes to studying glacier ice for records of past climates, the poles are easy: Antarctica and Greenland have huge ice caps that we can drill cores in to our hearts' content. The real problem is in the rest of the world, where we all live. Scientists cannot model the global climate of the past with data from the poles alone. So a newly published ice-core record from the tropics is real news.
Tropical glaciers are few, scattered and endangered. South America and the Himalaya have most of them, and nearly all have been shrinking rapidly for several decades. Professor Lonnie Thompson [ http://www.geology.ohio-state.edu/faculty_bios.php?id=52 ] of Ohio State University has specialized in drilling ice cores from them for more than 30 years, and the very first one he cored, in 1983, is a remote ice cap south of the equator in Peru named Quelccaya whose top sits above 18,000 feet. There he pioneered the use of a lightweight, solar-powered drill rig and succeeded in collecting two complete cores through the ice, about 160 meters long. Unable to keep them frozen, he had to cut them into sections and let them melt, then brought the water home in bottles.
Twenty years later Thompson returned and brought two new cores, intact this time, to Ohio State's ice locker. In a paper published today in Science [ http://www.sciencemag.org/content/early/2013/04/03/science.1234210 ], Thompson's team shows that the 1983 and 2003 cores faithfully preserve a year-by-year record of tropical climate 18 centuries long, extending back to the year 683 with annual resolution and a little less perfectly back to almost 200. Thompson calls it "the longest and highest-resolution tropical ice core record to date."
The possibility of retrieving such precise records was what excited Thompson from the beginning. The ice consists of spectacular annual layers that represent dry winters and wet summers. The winter layers collect the lion's share of the year's dust and dissolved chemicals while the summer layers represent rainwater from the Atlantic Ocean, filtered through the tropical Amazon basin.
Annual layers in the Quelccaya ice cap are about 75 centimeters thick.
Lonnie Thompson photo
The data from the Quelccaya cores shed light on many scientific problems related to climate. Most notably, the extent of summer snow from the east depends strongly on Pacific Ocean influences from the west, such as El Niño cycles—so strongly that the Atlantic snow record shows us the temperature of the Pacific as if in a mirror. And Pacific sea-surface temperature is one of the most important numbers in the planetary climate because it's the best gauge of how much water vapor enters the atmosphere.
Central Pacific sea-surface temperature (SST) during the last 1800 years reconstructed from the oxygen-isotope record of Quelccaya ice.
Image from Science
The climate record in the Quelccaya cores gives us the nearest thing to real truth in the centuries before modern science. It helps sharpen the picture provided by other ice cores, especially those in the tropics. And that in turn makes global climate records, and the models built upon them, more robust as we peer into the past and future.
We have little time to waste. Thompson's latest expedition to Quelccaya documented hundreds of meters of shrinkage since his first visit. Newly exposed plant remains at the glacier's retreating edges were found to be 6000 years old. And the top layers of ice, deposited since Thompson's first visit, show signs of summer melting for the first time in the entire record.
Copyright 2013 KQED
http://science.kqed.org/quest/2013/04/04/a-new-rosetta-stone-tropical-ice-core/ [with comments]
--
Tropical Ice Reveals Rare Climate Record
This photo from a 1977 expedition to Quelccaya Ice Cap in Peru shows annual layers of ice and dust visible in the ice cap's margin. ( Lonnie Thompson, Ohio State University )
This is a shot of Quelccaya Ice Cap in Peru's Andes mountains, taken from the same spot as the 1977 photo. It shows the glacier's retreat. ( Lonnie Thompson, Ohio State University )
04 April 2013
http://www.livescience.com/28438-tropical-glaciers-climate-change-clues.html [no comments yet], http://science.nbcnews.com/_news/2013/04/04/17604289-tropical-ice-offers-up-a-rare-climate-record [with comments]
--
In Sign of Warming, 1,600 Years of Ice in Andes Melted in 25 Years
[interactive image embedded]
The Qori Kalis glacier in Peru, a tongue of ice extending down a valley from the mighty Quelccaya ice cap, has been melting rapidly. Pull the slider with your mouse to compare a picture taken in 1978, left, with one taken in 2011.
Both images: Lonnie G. Thompson/Ohio State University
By JUSTIN GILLIS
Published: April 4, 2013
Glacial ice in the Peruvian Andes that took at least 1,600 years to form has melted in just 25 years, scientists reported Thursday, the latest indication that the recent spike in global temperatures has thrown the natural world out of balance.
The evidence comes from a remarkable find at the margins of the Quelccaya ice cap [ http://www.dailygalaxy.com/my_weblog/2009/07/the-quelccaya-ice-cap-the-worlds-largest-tropical-ice-field.html ] in Peru [ http://topics.nytimes.com/top/news/international/countriesandterritories/peru/index.html ], the world’s largest tropical ice sheet. Rapid melting there in the modern era is uncovering plants that were locked in a deep freeze when the glacier advanced many thousands of years ago.
Dating of those plants, using a radioactive form of carbon in the plant tissues that decays at a known rate, has given scientists an unusually precise method of determining the history of the ice sheet’s margins.
Lonnie G. Thompson [ http://www.nytimes.com/2012/07/03/science/earth/lonnie-thompson-climate-scientist-battles-time.html (the post to which this is a reply)], the Ohio State University [ http://topics.nytimes.com/top/reference/timestopics/organizations/o/ohio_state_university/index.html ] glaciologist whose team has worked intermittently on the Quelccaya ice cap for decades, reported the findings in a paper [ http://www.sciencemag.org/content/early/2013/04/03/science.1234210 ] released online Thursday by the journal Science.
The paper includes a long-awaited analysis of chemical tracers in ice cylinders the team recovered by drilling deep into Quelccaya, a record that will aid scientists worldwide in reconstructing past climatic variations.
Such analyses will take time, but Dr. Thompson said preliminary evidence shows, for example, that the earth probably went through a period of anomalous weather at around the time of the French Revolution, which began in 1789. The weather presumably contributed to the food shortages that exacerbated that upheaval.
“When there’s a disruption of food, this is bad news for any government,” Dr. Thompson said in an interview.
Of greater immediate interest, Dr. Thompson and his team have expanded on previous research involving long-dead plants emerging from the melting ice at the edge of Quelccaya, a huge, flat ice cap sitting on a volcanic plain 18,000 feet above sea level.
Several years ago, the team reported on plants that had been exposed near a meltwater lake. Chemical analysis showed them to be about 4,700 years old, proving that the ice cap had reached its smallest extent in nearly five millenniums.
In the new research, a thousand feet of additional melting has exposed plants that laboratory analysis shows to be about 6,300 years old. The simplest interpretation, Dr. Thompson said, is that ice that accumulated over approximately 1,600 years melted back in no more than 25 years.
“If any time in the last 6,000 years these plants had been exposed for any five-year period, they would have decayed,” Dr. Thompson said. “That tells us the ice cap had to be there 6,000 years ago.”
Meredith A. Kelly, a glacial geomorphologist at Dartmouth College who trained under Dr. Thompson but was not involved in the new paper, said his interpretation of the plant remains was reasonable.
Her own research on Quelccaya suggests that the margins of the glacier have melted quite rapidly at times in the past. But the melting now under way appears to be at least as fast, if not faster, than anything in the geological record since the end of the last ice age, she said.
Global warming, which scientists say is being caused primarily by the human release of greenhouse gases, is having its largest effects at high latitudes and high altitudes. Sitting at high elevation in the tropics, the Quelccaya ice cap appears to be extremely sensitive to the temperature changes, several scientists said.
“It may not go very quickly because there’s so much ice, but we might have already locked into a situation where we are committed to losing that ice,” said Mathias Vuille, a climate scientist at the State University at Albany in New York.
Throughout the Andes, glaciers are now melting so rapidly that scientists have grown deeply concerned about water supplies for the people living there. Glacial meltwater is essential for helping Andean communities get through the dry season.
In the short run, the melting is producing an increase of water supplies and feeding population growth in major cities of the Andes, the experts said. But as the glaciers continue shrinking, trouble almost certainly looms.
Douglas R. Hardy, a University of Massachusetts researcher who works in the region, said, “How much time do we have before 50 percent of Lima’s or La Paz’s water resources are gone?”
*
Related
Climate Maverick to Retire From NASA (April 2, 2013)
http://www.nytimes.com/2013/04/02/science/james-e-hansen-retiring-from-nasa-to-fight-global-warming.html
Related in Opinion
Op-Ed Columnist: Cooling on Warming (March 28, 2013)
http://www.nytimes.com/2013/03/28/opinion/collins-cooling-on-warming.html
*
© 2013 The New York Times Company
http://www.nytimes.com/2013/04/05/world/americas/1600-years-of-ice-in-perus-andes-melted-in-25-years-scientists-say.html [excerpted at/see (linked in) http://investorshub.advfn.com/boards/read_msg.aspx?message_id=86519462 (and any future following)]
--
(linked in):
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=77869081 and preceding and following
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=82499392 and preceding and following
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=83619760 and preceding and following
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http://investorshub.advfn.com/boards/read_msg.aspx?message_id=86524946 and preceding (and any future following)
The Quelccaya ice cap, 12 kilometers across, is the largest icefield in South America.
Google Maps image
by Andrew Alden
Apr 04, 2013
When it comes to studying glacier ice for records of past climates, the poles are easy: Antarctica and Greenland have huge ice caps that we can drill cores in to our hearts' content. The real problem is in the rest of the world, where we all live. Scientists cannot model the global climate of the past with data from the poles alone. So a newly published ice-core record from the tropics is real news.
Tropical glaciers are few, scattered and endangered. South America and the Himalaya have most of them, and nearly all have been shrinking rapidly for several decades. Professor Lonnie Thompson [ http://www.geology.ohio-state.edu/faculty_bios.php?id=52 ] of Ohio State University has specialized in drilling ice cores from them for more than 30 years, and the very first one he cored, in 1983, is a remote ice cap south of the equator in Peru named Quelccaya whose top sits above 18,000 feet. There he pioneered the use of a lightweight, solar-powered drill rig and succeeded in collecting two complete cores through the ice, about 160 meters long. Unable to keep them frozen, he had to cut them into sections and let them melt, then brought the water home in bottles.
Twenty years later Thompson returned and brought two new cores, intact this time, to Ohio State's ice locker. In a paper published today in Science [ http://www.sciencemag.org/content/early/2013/04/03/science.1234210 ], Thompson's team shows that the 1983 and 2003 cores faithfully preserve a year-by-year record of tropical climate 18 centuries long, extending back to the year 683 with annual resolution and a little less perfectly back to almost 200. Thompson calls it "the longest and highest-resolution tropical ice core record to date."
The possibility of retrieving such precise records was what excited Thompson from the beginning. The ice consists of spectacular annual layers that represent dry winters and wet summers. The winter layers collect the lion's share of the year's dust and dissolved chemicals while the summer layers represent rainwater from the Atlantic Ocean, filtered through the tropical Amazon basin.
Annual layers in the Quelccaya ice cap are about 75 centimeters thick.
Lonnie Thompson photo
The data from the Quelccaya cores shed light on many scientific problems related to climate. Most notably, the extent of summer snow from the east depends strongly on Pacific Ocean influences from the west, such as El Niño cycles—so strongly that the Atlantic snow record shows us the temperature of the Pacific as if in a mirror. And Pacific sea-surface temperature is one of the most important numbers in the planetary climate because it's the best gauge of how much water vapor enters the atmosphere.
Central Pacific sea-surface temperature (SST) during the last 1800 years reconstructed from the oxygen-isotope record of Quelccaya ice.
Image from Science
The climate record in the Quelccaya cores gives us the nearest thing to real truth in the centuries before modern science. It helps sharpen the picture provided by other ice cores, especially those in the tropics. And that in turn makes global climate records, and the models built upon them, more robust as we peer into the past and future.
We have little time to waste. Thompson's latest expedition to Quelccaya documented hundreds of meters of shrinkage since his first visit. Newly exposed plant remains at the glacier's retreating edges were found to be 6000 years old. And the top layers of ice, deposited since Thompson's first visit, show signs of summer melting for the first time in the entire record.
Copyright 2013 KQED
http://science.kqed.org/quest/2013/04/04/a-new-rosetta-stone-tropical-ice-core/ [with comments]
--
Tropical Ice Reveals Rare Climate Record
This photo from a 1977 expedition to Quelccaya Ice Cap in Peru shows annual layers of ice and dust visible in the ice cap's margin. ( Lonnie Thompson, Ohio State University )
This is a shot of Quelccaya Ice Cap in Peru's Andes mountains, taken from the same spot as the 1977 photo. It shows the glacier's retreat. ( Lonnie Thompson, Ohio State University )
04 April 2013
http://www.livescience.com/28438-tropical-glaciers-climate-change-clues.html [no comments yet], http://science.nbcnews.com/_news/2013/04/04/17604289-tropical-ice-offers-up-a-rare-climate-record [with comments]
--
In Sign of Warming, 1,600 Years of Ice in Andes Melted in 25 Years
[interactive image embedded]
The Qori Kalis glacier in Peru, a tongue of ice extending down a valley from the mighty Quelccaya ice cap, has been melting rapidly. Pull the slider with your mouse to compare a picture taken in 1978, left, with one taken in 2011.
Both images: Lonnie G. Thompson/Ohio State University
By JUSTIN GILLIS
Published: April 4, 2013
Glacial ice in the Peruvian Andes that took at least 1,600 years to form has melted in just 25 years, scientists reported Thursday, the latest indication that the recent spike in global temperatures has thrown the natural world out of balance.
The evidence comes from a remarkable find at the margins of the Quelccaya ice cap [ http://www.dailygalaxy.com/my_weblog/2009/07/the-quelccaya-ice-cap-the-worlds-largest-tropical-ice-field.html ] in Peru [ http://topics.nytimes.com/top/news/international/countriesandterritories/peru/index.html ], the world’s largest tropical ice sheet. Rapid melting there in the modern era is uncovering plants that were locked in a deep freeze when the glacier advanced many thousands of years ago.
Dating of those plants, using a radioactive form of carbon in the plant tissues that decays at a known rate, has given scientists an unusually precise method of determining the history of the ice sheet’s margins.
Lonnie G. Thompson [ http://www.nytimes.com/2012/07/03/science/earth/lonnie-thompson-climate-scientist-battles-time.html (the post to which this is a reply)], the Ohio State University [ http://topics.nytimes.com/top/reference/timestopics/organizations/o/ohio_state_university/index.html ] glaciologist whose team has worked intermittently on the Quelccaya ice cap for decades, reported the findings in a paper [ http://www.sciencemag.org/content/early/2013/04/03/science.1234210 ] released online Thursday by the journal Science.
The paper includes a long-awaited analysis of chemical tracers in ice cylinders the team recovered by drilling deep into Quelccaya, a record that will aid scientists worldwide in reconstructing past climatic variations.
Such analyses will take time, but Dr. Thompson said preliminary evidence shows, for example, that the earth probably went through a period of anomalous weather at around the time of the French Revolution, which began in 1789. The weather presumably contributed to the food shortages that exacerbated that upheaval.
“When there’s a disruption of food, this is bad news for any government,” Dr. Thompson said in an interview.
Of greater immediate interest, Dr. Thompson and his team have expanded on previous research involving long-dead plants emerging from the melting ice at the edge of Quelccaya, a huge, flat ice cap sitting on a volcanic plain 18,000 feet above sea level.
Several years ago, the team reported on plants that had been exposed near a meltwater lake. Chemical analysis showed them to be about 4,700 years old, proving that the ice cap had reached its smallest extent in nearly five millenniums.
In the new research, a thousand feet of additional melting has exposed plants that laboratory analysis shows to be about 6,300 years old. The simplest interpretation, Dr. Thompson said, is that ice that accumulated over approximately 1,600 years melted back in no more than 25 years.
“If any time in the last 6,000 years these plants had been exposed for any five-year period, they would have decayed,” Dr. Thompson said. “That tells us the ice cap had to be there 6,000 years ago.”
Meredith A. Kelly, a glacial geomorphologist at Dartmouth College who trained under Dr. Thompson but was not involved in the new paper, said his interpretation of the plant remains was reasonable.
Her own research on Quelccaya suggests that the margins of the glacier have melted quite rapidly at times in the past. But the melting now under way appears to be at least as fast, if not faster, than anything in the geological record since the end of the last ice age, she said.
Global warming, which scientists say is being caused primarily by the human release of greenhouse gases, is having its largest effects at high latitudes and high altitudes. Sitting at high elevation in the tropics, the Quelccaya ice cap appears to be extremely sensitive to the temperature changes, several scientists said.
“It may not go very quickly because there’s so much ice, but we might have already locked into a situation where we are committed to losing that ice,” said Mathias Vuille, a climate scientist at the State University at Albany in New York.
Throughout the Andes, glaciers are now melting so rapidly that scientists have grown deeply concerned about water supplies for the people living there. Glacial meltwater is essential for helping Andean communities get through the dry season.
In the short run, the melting is producing an increase of water supplies and feeding population growth in major cities of the Andes, the experts said. But as the glaciers continue shrinking, trouble almost certainly looms.
Douglas R. Hardy, a University of Massachusetts researcher who works in the region, said, “How much time do we have before 50 percent of Lima’s or La Paz’s water resources are gone?”
*
Related
Climate Maverick to Retire From NASA (April 2, 2013)
http://www.nytimes.com/2013/04/02/science/james-e-hansen-retiring-from-nasa-to-fight-global-warming.html
Related in Opinion
Op-Ed Columnist: Cooling on Warming (March 28, 2013)
http://www.nytimes.com/2013/03/28/opinion/collins-cooling-on-warming.html
*
© 2013 The New York Times Company
http://www.nytimes.com/2013/04/05/world/americas/1600-years-of-ice-in-perus-andes-melted-in-25-years-scientists-say.html [excerpted at/see (linked in) http://investorshub.advfn.com/boards/read_msg.aspx?message_id=86519462 (and any future following)]
--
(linked in):
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=77869081 and preceding and following
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=82499392 and preceding and following
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=83619760 and preceding and following
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=84347999 and preceding and following
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=86524946 and preceding (and any future following)
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