Antarctic ice shelf set to collapse due to warm

[giovonni]

Antarctic ice shelf set to collapse due to warm

By Alister Doyle, Environment Correspondent

WILKINS ICE SHELF, Antarctica (Reuters) - A huge Antarctic ice shelf is on the brink of collapse with just a sliver of ice holding it in place, the latest victim of global warming that is altering maps of the frozen continent.

"We've come to the Wilkins Ice Shelf to see its final death throes," David Vaughan, a glaciologist at the British Antarctic Survey (BAS), told Reuters after the first -- and probably last -- plane landed near the narrowest part of the ice.

read more;
http://www.reuters.com/article/envir...nnel=0&sp=true

[Dantheman62]

The European Space Agency is also keeping an eye on this.......
under threat
http://www.esa.int/esaCP/SEMXK5AWYNF_index_0.html






28 November 2008
New rifts have developed on the Wilkins Ice Shelf that could lead to the opening of the ice bridge that has been preventing the ice shelf from disintegrating and breaking away from the Antarctic Peninsula.

The ice bridge connects the Wilkins Ice Shelf to two islands, Charcot and Latady. As seen in the Envisat image above acquired on 26 November 2008, new rifts (denoted by colourful lines and dates of the events) have formed to the east of Latady Island and appear to be moving in a northerly direction.

Dr Angelika Humbert from the Institute of Geophysics, Münster University, and Dr Matthias Braun from the Center for Remote Sensing, University of Bonn, spotted the newly formed rifts during their daily monitoring activities of the ice sheet via Envisat Advanced Synthetic Aperture Radar (ASAR) acquisitions. "These new rifts, which have joined previously existing rifts on the ice shelf (blue dotted line), threaten to break up the chunk of ice located beneath the 21 July date, which would cause the bridge to lose its stabilisation and collapse," Humbert explained. "These recent changes are happening slower and more continuously than the events we saw earlier this year."

[alyscat]

OK, because I've just spent an incredibly busy day and am actually RELAXING reading PA (LOL) can someone tell us off the top of their head if this is ice already floating in the water, or new ice in the water (the latter means seawater levels with rise, the former is no change -
alys

[Dantheman62]

HaHa good point, I believe it is floating ice but once it goes then the land ice is next to go. I will check the site and respond back!

[Dantheman62]

here ya go!......
The Wilkins Ice Shelf, a broad plate of floating ice south of South America on the Antarctic Peninsula, had been stable for most of the last century before it began retreating in the 1990s. The peninsula has been experiencing extraordinary warming in the past 50 years of 2.5°C.

If the ice shelf breaks away from the peninsula, it will not cause a rise in sea level since it is already floating. However, ice shelves on the Antarctic Peninsula are sandwiched by extraordinarily raising surface air temperatures and a warming ocean, making them important indicators for on-going climate change.

Long-term satellite monitoring over Antarctica is important because it provides authoritative evidence of trends and allows scientists to make predictions. Over the last 17 years, ESA’s ERS and Envisat satellite missions have been the main vehicles for testing and demonstrating the use of Earth Observation data in Polar Regions.

[alyscat]

the monks at HPH are now talking about the = gosh, how do I say this so that the bots don';t pick it back up and feed it into the data --- projected worldwide excitement that will happen on the coasts will be a multimonth process. It could be x number of months of watching something like a major ice thingy break off and slide into the water (among other possibilities).

alys

[Dantheman62]

Yeah that's why they're watching the melt closely, because if the ice shelves break off then that's an indicator that temperatures are rising and the land ice is next if it continues. That will eventually make the sea level rise and also if enough melts it will change the salinity of the oceans which will affect everything from ship buoyancy to sea life.

[BROOK]

I really don't know the answer to this question...but is the ice shelf not made of Sea water?
I always thought it was ocean water..doh

[Dantheman62]

Ask and you shall receive BROOK!....
What is sea ice?

Sea ice is simply frozen ocean water. It forms, grows, and melts in the ocean. In contrast, icebergs, glaciers, ice sheets, and ice shelves all originate on land. Sea ice occurs in both the Arctic and Antarctic. In the Northern Hemisphere, it can currently exist as far south as Bohai Bay, China (approximately 38 degrees north latitude), which is actually about 700 kilometers (435 miles) closer to the Equator than it is to the North Pole. In the Southern Hemisphere, sea ice only develops around Antarctica, occurring as far north as 55 degress south latitude.

Sea ice grows during the winter months and melts during the summer months, but some sea ice remains all year in certain regions. About 15 percent of the world's oceans are covered by sea ice during part of the year.

Can you drink melted sea ice?

New ice is usually very salty because it contains concentrated droplets called brine that are trapped in pockets between the ice crystals, and so it would not make good drinking water. As ice ages, the brine eventually drains through the ice, and by the time it becomes multiyear ice, nearly all of the brine is gone. Most multiyear ice is fresh enough that someone could drink its melted water. In fact, multiyear ice often supplies the fresh water needed for polar expeditions

[BROOK]

Thanks Dan....There's not a day goes by I don't learn something new