Glacier slides twice as fast towards the sea

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 10 May 2010

A glacier in Greenland slides up to 220 percent faster towards the sea in summer than in winter and global warming could mean a wider acceleration that would raise sea levels, according to a study published on Sunday.

An iceberg carved from a glacier floats in the Jacobshavn fjord in south-west Greenland- Reuters

A group of experts led by Ian Bartholomew at Edinburgh University in Scotland said the variability was much stronger than earlier observations of glacier movement in Greenland.

The study, published in the journal Nature Geoscience, is a new piece of a puzzle to understand the world’s second biggest ice sheet behind Antarctica. Greenland has enough ice to raise world sea levels by about seven metres if it all melted.

The study said GPS satellite measurements of the glacier in south-west Greenland, up to 35km inland and at altitudes of up to 1 095m, showed that the ice in some places slid at 300m per year at peak summer rates.

“Our measurements reveal substantial increases in ice velocity during summer, up to 220 percent above winter background values,” it said.

The scientists said that the summer slide might be linked to melt water seeping under the ice. It did not speculate if the change in speed between summer and winter was part of natural shifts or was influenced by a changing climate.

But they wrote: “In a warming climate, with longer and more intense summer melt seasons, we would expect that water will reach the bed farther inland and a larger portion of the ice sheet will experience summer velocity changes.”

The United Nations panel of climate experts said in 2007 that global warming was unequivocal and that it was more than 90 percent certain that most warming in the past half century was caused by human activities led by the burning of fossil fuels.

The UN panel has come under fire this year after officials said its latest report in 2007 exaggerated the pace of melt of Himalayan glaciers by saying they might all disappear by 2035.

More than 250 members of the US National Academy of Sciences on Thursday defended climate change research against “political assaults”, and said that any delay in tackling global warming heightens the risk of a planet-wide catastrophe.

-Reuters

Peruvian glacier breaks causing tsunami

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 13 April 2010

A huge glacier broke off and plunged into a lake in Peru, causing a 23m tsunami wave that swept away at least three people and destroyed a water processing plant serving 60 000 local residents, government officials said on Monday.

Hualcan, north of Huaraz

The ice block tumbled into a lake in the Andes on Sunday near the town of Carhuaz, 320km north of the capital, Lima. Three people were feared buried in debris.

Investigators said the chunk of ice from the Hualcan glacier measured 500m by 200m.

“This slide into the lake generated a tsunami wave, which breached the lake’s levees, which are 23 metres high – meaning the wave was 23 metres high,” said Patricio Vaderrama, an expert on glaciers at Peru’s Institute of Mine Engineers.

Authorities evacuated mountain valleys, fearing more breakages.

It was one of the most concrete signs yet that glaciers are disappearing in Peru, home to 70 percent of the world’s tropical icefields. Scientists say warmer temperatures will cause them to melt away altogether within 20 years.

In 1970, not far from Carhuaz, an earthquake triggered an avalanche of ice, rock and mud on the mountain of Huascaran that buried the town of Yungay, killing more than 20 000 people who lived below Peru’s tallest peak, which sits 6 768m above sea level.
– Reuters