Archive for ‘Glaciers & Ice Sheets’

US scientist in race to learn from Indonesia’s dying glacier

Friday, July 2nd, 2010

The only glacier in the western Pacific could disappear in less than five years, taking with it vital clues about the earth’s changing climate, a US scientist said Friday.

Ohio State University Professor Lonnie Thompson has just completed what he calls a “salvage mission” to extract ice cores from the glacier on Punjak Jaya, which soars above the tropical, reef-fringed waters of eastern Indonesia.

The ice core samples he collected after his 13-day trip to the Papuan central highlands are set to be shipped back to Chicago on Wednesday for further analysis.

But Thompson said one thing is clear: the glacier is dying.

“This is the only ice in the western end of the Pacific warm pool, which is the warmest water on earth. When it melts that history (from ice cores) is lost forever and there’s no way we can recapture it,” he told AFP.

“My biggest concern is that we may be too late to capture that history. Some is already missing from the top and from the bottom. How much of that history do we still have?”

Thompson estimated the glacier is disappearing at a rate of seven metres (22 feet) a year. As it is only about 32 metres deep, it could be gone in four or five years.

“Looking at the loss of ice that’s been occurring since the 1830s we thought that we were looking at decades (before the Punjak Jaya ice disappeared),” he said.

“But I’ve never been to a glacier anywhere else in the world where it rains every day… If it rains on a glacier then that’s the death of the glacier.”

One of the world’s leading experts, Thompson has visited glaciers from Kenya to Peru. But he said he had never seen anything like what he experienced in Papua, where the ice was visibly melting under his tent.

“It’s the first glacier that I’ve visited where you can hear the water flowing underneath the ice,” he said.

The 88 metres of ice samples from his expedition will be added to the Ohio State University’s valuable archive of tropical ice cores, where it will remain available for researchers years after the glacier itself may have gone.

The study of glacier ice reveals evidence of past climate fluctuations, which can then be referenced with samples from other parts of the planet to get a better understanding of current climate change.

“We hope to be able to reconstruct past temperatures, look at the history of the ice here and compare that with ice from around the world, particularly with ice from the other side of the Pacific Ocean,” Thompson said.

He said he hoped to publish his findings early next year.

Source: US scientist in race to learn from Indonesia’s dying glacier – news.asiaone

Date: 02 July 2010

Ridge clue to Antarctic ice loss

Sunday, June 20th, 2010
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Pine Island Glacier is one of the largest in Antarctica

The discovery of an underwater ridge in West Antarctica could help explain why there has been an acceleration in the ice flowing from a glacier in the area.

Researchers suggest that the base of Pine Island Glacier once sat on the ridge, but recently became detached from the feature.

The team made the discovery during surveys that used a unmanned submarine to examine waters under the glacier.

The findings have been published in the journal Nature Geoscience.

“We found something very unexpected,” said co-author Pierre Dutrieux, from the British Antarctic Survey (BAS), referring to the 400m-high ridge.

“Acoustic instruments on the submarine told us that there was a ridge at the bottom of the ocean, sitting transverse to the flow of ice.”

Dr Dutrieux said that there was also evidence that the base of the glacier was once attached to the ridge.

“Some decades ago, the glacier was sitting on this ridge and the friction of the ridge was restraining the flow of the glacier,” he explained.

“When the glacier became detached from the ridge, the ice flow was able to accelerate significantly.”

The highlighted area shows a dense concentration of crevasses along one edge of the glacier. Large numbers of deep crevasses are a sign that parts of the glacier are moving rapidly

The highlighted area shows a dense concentration of crevasses along one edge of the glacier. Large numbers of deep crevasses are a sign that parts of the glacier are moving rapidly

The highlighted area shows a dense concentration of crevasses along one edge of the glacier. Large numbers of deep crevasses are a sign that parts of the glacier are moving rapidly.

Dr Dutrieux said that the glacier was located in an area where there was intense melting of land ice, which was flowing into the ocean and contributing to sea level rise.

Researchers estimate that the accelerating flow of glaciers in West Antarctica is contributing about 10% of the observed rise in the mean global sea level.

In 2009, a study of satellite measurements of Pine Island Glacier, which is one of the largest in Antarctica, revealed the surface of the ice was falling at a rate of up to 16m a year.

It added that the glacier was thinning four times faster than it was a decade earlier.

Ice dynamics

Dr Dutrieux said that the discovery of the ridge was an important piece in the jig-saw of factors that could be changing the ice dynamics in the region.

“We have not had a clear understanding of what is driving this melting because the atmospheric forcing – the temperature at the surface – is not warm enough to cause such a melting,” he added.

“So the hypothesis was that it was coming from the ocean, which was melting the ice shelf from below.”

To gather the data, the team launched an Autonomous Underwater Vehicle (AUV) on six survey missions beneath the floating tongue of Pine Island Glacier.

The submersible was designed and built by a team from the National Oceanography Centre in Southampton, and funded by the UK’s Natural Environment Research Council (Nerc).

The seven-metre long vessel, with a range of 400km, carried a multibeam sonar system that allowed it to build up a 3D map of the ocean bed below and ice above.

The AUV has the capability to dive to depths of 1,600m below the surface

The AUV has the capability to dive to depths of 1,600m below the surface

It also was fitted with devices that measured salinity, temperature and oxygen concentrations in the sea water.

This allowed the researchers to gain a better understanding of the flow of water within the ice cavity and the rate of melting.

“We now know that there is relatively warm water beneath this floating ice,” observed Dr Dutrieux, “so this warm water could have been able to melt the base of the ice shelf.

“Another process leading to the ice becoming detached from the ridge could have been a change in the water properties that was grinding the shelf from beneath.”

He said the presence of the ridge would change the basis of future work on ice dynamics in the area.

“Topography is the main thing that constrains ice flow so, basically, it is going to fundamentally change the way people think about this glacier and the way we understand how it behaves.”

Source: Ridge clue to Antarctic ice loss – news.bbc.co.uk

Date: 20 June 2010

Yellow sub finds clues to Antarctic glacier’s thaw

Sunday, June 20th, 2010

A yellow submarine has helped to solve a puzzle about one of Antarctica’s fastest-melting glaciers, adding to concerns about how climate change may push up world sea levels, scientists said on Sunday.

The robot submarine, deployed under the ice shelf floating on the sea at the end of the Pine Island Glacier, found that the ice was no longer resting on a subsea ridge that had slowed the glacier’s slide until the early 1970s.

Antarctica is key to predicting the rise in sea levels caused by global warming — it has enough ice to raise sea levels by 57 metres (187 ft) if it ever all melted. Even a tiny thaw at the fringes could swamp coasts from Bangladesh to Florida.

The finding from the 2009 mission “only adds to our concern that this region is indeed the ‘weak underbelly’ of the West Antarctic Ice Sheet”, co-author of the study Stan Jacobs at the Lamont-Doherty Earth Observatory said in a statement.

West Antarctica’s thaw accounts for 10 percent of a recently observed rise in sea levels, with melting of the Pine Island glacier quickening, especially in recent decades, according to the study led by the British Antarctic Survey (BAS) and published in the journal Nature Geoscience.

Loss of contact with the subsea ridge meant that ice was flowing faster and also thawing more as sea water flowed into an ever bigger cavity that now extended 30 km beyond the ridge. The water was just above freezing at 1 degree Celsius (33.80F).

SATELLITE BUMP

Satellite photographs in the early 1970s had shown a bump on the surface of the ice shelf, indicating the subsea ridge. That bump has vanished and the 7 metre (22 foot) submarine found the ridge was now up to 100 metres below the ice shelf.

Adrian Jenkins, lead author at BAS, said the study raised “new questions about whether the current loss of ice from Pine Island Glacier is caused by recent climate change or is a continuation of a longer-term process that began when the glacier disconnected from the ridge”.

Pierre Dutrieux, also at BAS, said the ice may have started thinning because of some as yet-unknown mechanism linked to climate change.

“It could be a shift in the wind, due to a change in climate, that pushed more warm water under the shelf,” he told Reuters.

The U.N. panel of climate scientists projected in 2007 that world sea levels could rise by between 18 and 59 cm (7-24 inches) by 2100, excluding risks of faster melting in Antarctica and Greenland.

Source: Yellow sub finds clues to Antarctic glacier’s thaw - AlertNet

Date: 20 June 2010

Arctic sea ice melting faster: Study

Thursday, June 17th, 2010

Arctic sea ice melted 50% faster than the average rate during May 2010, with combined global land and ocean surface temperature being the warmest on record for the period from January-May, studies have suggested.

Research at the US National Oceanic and Atmospheric Administration (NOAA) has shown that the combined global land and ocean surface temperature was the warmest on record for the period from January-May.

During May 2010, Arctic sea ice melted 50% faster than the average May melting rate, according to the National Snow and Ice Data Centre.

Source: Arctic sea ice melting faster: Study – economictimes.indiatimes

Date: 17 June, 2010

May 2010 was warmest on record – US govt data

Wednesday, June 16th, 2010

Last month was the warmest May on record, the U.S. National Oceanic and Atmospheric Administration said on Tuesday.

It was also the 303rd consecutive month that was hotter than the 20th century global average for that month, according to Deke Arndt, chief of the climate monitoring at NOAA’s National Climatic Data Center.

The long-term warming trend, along with reports that Arctic sea ice covered less of the ocean and snow covered less ground around the world in May, is consistent with the science of climate change, Arndt said.

Many climate scientists believe that Earth’s surface is warming, due in part to the emission of heat-trapping greenhouse gases, including carbon dioxide.

Source: May 2010 was warmest on record – US govt data – Reuters

Date: 16 June, 2010

Climate Change Increases Hazard Risk in Alpine Regions, Study Shows

Tuesday, June 15th, 2010

Climate change could cause increasing and unpredictable hazard risks in mountainous regions, according to a new study from the University of Exeter and Austrian researchers. The study analyzes the effects of two extreme weather events — the 2003 heatwave and the 2005 flood — on the Eastern European Alps. It demonstrates what impact events like these, predicted to become more frequent under a changing climate, could have on alpine regions and what implications these changes might have for local communities.

The mean summer temperatures during the 2003 heat wave in a large area of the European Alps exceeded the 1961-1990 mean by 3-5˚C. This triggered a record Alpine glacier loss that was three times above the 1980-2000 average. Furthermore, melting permafrost caused increased rock-fall activity.

The severe floods that occurred as a result of heavy rainfall in August 2005 were the most damaging for 100 years and led to high volumes of water and sediment being deposited downstream, causing an estimated €555 million worth of damage in Austria to buildings, railways, roads and industrial areas. In Switzerland, this has been estimated to have caused one quarter of all damage by floods, debris flows, landslides and rock falls recorded since 1972.

Source: Climate Change Increases Hazard Risk in Alpine Regions, Study Shows - Science Daily

Date: 15 June, 2010

As Humans Advance, Andean Glaciers Recede

Monday, June 14th, 2010

The spectacular glacier Number 15 of Antisana, one of the Ecuadorean capitals’ sources of potable water, lost at least 36 percent of its original mass in the last 50 years.

The Antisana is a snow-capped peak of the eastern branch of the Andes range whose three humps can be seen from Quito on clear days. It is located at the same latitude as the capital, 50 kilometres to the east.

Because of its strategic importance, it is the most studied of these Andean peaks. The glacier’s length is measured each year and its mass each month, as part of tracking efforts by France’s Institute of Research for Development (IRD), Ecuador’s National Meteorology and Hydrology Institute (INAMHI) and Quito’s Metropolitan Sewage and Potable Water Agency (EMAAP-Q).

Cotopaxi, one of the world’s highest active volcanoes, whose snow-covered cone can also be seen from Quito, lost 40 percent of its glacial mass between 1976 and 2006, said Bernard Francou, IRD representative in Ecuador, in a Tierramérica interview.

The studies by IRD and its local counterparts have shown that the same thing is happening to Ecuador’s glaciers as to those of the Real (Royal) 888 branch of the Andes, in Bolivia, and the Blanca range, in Peru and Colombia. They have lost 30 percent of their mass, on average.

In the case of glacier fields below 5,400 metres above sea level, the deterioration is greater, as is the case of Chacaltaya and Charquini in Bolivia, Broggi, Yanamarey and Pastoruri in Peru, and Carihuairazo in Ecuador, which scientists predict will disappear altogether within 10 to 20 years.

Source: As Humans Advance, Andean Glaciers Recede - ipsnews.net

Date: 14 June, 2010

Omani who scaled Everest raises concern about global warming

Friday, June 11th, 2010

Seeing is believing. We have heard a lot about global warming, but now an Omani mountaineer has witnessed it himself and brought his serious concerns to us all.

Omani adventurer Khalid Sulaiman Al Siyabi, who just returned from Nepal after summiting the Mount Everest, said that the biggest threat to the universe is the rapid CO2 emission resulting in ice-melting of the Himalayan mountains in Nepal.

In an interview with Khaleej Times in the capital, Al Siyabi gave details of his death-defying expedition and rapidly growing global warming.

Many countries could be on natural disaster threat because of the ice-melting of Himalaya.

“So far, we have learnt about ice-melting on mountains because of growing CO2 emissions but now I have experienced myself,” Al Siyabi said.

“I learnt a lot about eco-system and environment and we have to be very careful on what is happening around us. Global warming is really hitting us hard.

“I witnessed there a large amount of avalanches taking place around six to seven times a day,” Al Siyabi said.

“The ice is melting so fast, we need to think about it very seriously. We have to take initiatives for it and pay attention because whatever I have seen and experienced there, is precisely an eye-opener,” Al Siyabi said.

Al Siyabi defied all horrifying odds, hurdles and scaled Mount Everest, the highest mountain peak in the world at 8,848 metres above sea level.

Source: Omani who scaled Everest raises concern about global warming - Khaleej Times

Date: 11 June, 2010

Europe, US to see snowy, cold winters: expert

Friday, June 11th, 2010

Europe, North America and east Asia can expect more cold, moist and snowy winters such as the one just passed, a top scientist said Friday.

While it may seem counter-intuitive, warmer Arctic climes caused by climate change influence air pressure at the North Pole, shifting wind patterns in such a way as to boost cooling over adjacent swathes of the planet.

“Cold and snowy winters will be the rule rather than the exception,” said James Overland of the US National Oceanic and Atmospheric Administration.

Continued rapid loss of ice will be an important driver of major change in the world’s climate system in the coming years, he said at an Oslo meeting of scientists reviewing research from the two-year International Polar Year 2007-2008.

The exceptionally chilly winter of 2009-2010 in temperate zones of the northern hemisphere were connected to unique physical processes in the Arctic, he said.

“The emerging impact of greenhouse gases in an important factor in the changing Arctic,” he explained in a statement.

“What was not fully recognized until now is that a combination of an unusual warm period due to natural variability, loss of sea ice reflectivity, ocean heat storage, and changing wind patterns all working together to disrupt the memory and stability of the Arctic climate system,” he said.

The region is warming more than twice as fast as the rest of the planet, a phenomenon known as Arctic amplification.

Resulting ice loss is significantly greater than earlier climate models predicted.

The polar ice cap shrank to its smallest surface since records have been kept in 2007, and early data suggests it could become even smaller this summer.

“It is unlikely that the Arctic can return to its previous condition,” Overland said. “The changes are irreversible.”

Source: Europe, US to see snowy, cold winters: expert – france24

Date: 11 June, 2010

Arctic ice at low point compared to recent geologic history

Wednesday, June 2nd, 2010

Less ice covers the Arctic today than at any time in recent geologic history. That’s the conclusion of an international group of researchers, who have compiled the first comprehensive history of Arctic ice.

“The ice loss that we see today — the ice loss that started in the early 20th Century and sped up during the last 30 years — appears to be unmatched over at least the last few thousand years,” said Leonid Polyak, a research scientist at Byrd Polar Research Center at Ohio State University.

Polyak is lead author of the paper and a preceding report that he and his coauthors prepared for the U.S. Climate Change Science Program.

Source: Arctic ice at low point compared to recent geologic history – physorg

Date: 02 June, 2010

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