Arctic ice shelf splits

BBC News ^ | Tuesday, 23 September, 2003 | NA

[pa_dweller]

The largest ice shelf in the Arctic has fractured, releasing all the water from the freshwater lake it dammed.

The Ward Hunt Ice Shelf is located on the north coast of Ellesmere Island in Canada's Nunavut territory.

The huge mass of floating ice, which has been in place for at least 3,000 years, is now in two major pieces.

The scientists who report the break-up in the journal Geophysical Research Letters (GRL) say it is further evidence of ongoing and accelerated climate change in the north polar region.

The researchers - Warwick Vincent and Derek Mueller of Laval University in Quebec City, Canada; and Martin Jeffries of the University of Alaska Fairbanks, US - have been studying the shelf onsite and through satellite radar imagery and helicopter overflights.

Lost water

They say the fracturing - which has been developing since the spring of 2000 - is the end result of a three-decade-long decline.

"We're now seeing some very extensive fractures in it that extend many kilometres horizontally across the ice-shelf; and they extend all the way through from the top to the bottom, many tens of metres through the ice shelf. And we've never seen fractures like this," Dr Jeffries told the BBC.

They warn that major free-floating ice islands could pose a danger to shipping and to drilling platforms in the Beaufort Sea.

The immediate consequence of the rupture has been the loss of almost all of the freshwater from the Northern Hemisphere's largest epishelf lake (a body of mostly freshwater trapped behind an ice shelf).

The freshwater lay in the 30-kilometre- [20-mile] long Disraeli Fiord.

At its deepest, the freshwater measured 43 metres [140 feet], and sat atop 360 metres [1,200 feet] of denser ocean water.

Other worlds

The loss of fresh and brackish water has changed the environment for the microscopic animals and algae living in the area.

"These are very rare and unusual ecosystems and they have been studied as possible analogues for life on a colder Earth and life on the planets," Dr Jeffries said.

"And if we are losing them, we are losing the opportunity to study life earlier in Earth history and elsewhere in the Solar System."

Scientists monitor continuously ice-shelf development in both the Arctic and the Antarctic.

In the southern polar region, recent times have witnessed some dramatic changes.

Last year, the 3,250-square-km Larsen B Ice Shelf on the Antarctic Peninsula shattered over a period of a month into thousands of icebergs.

The peninsula is one of the three fastest-warming regions on Earth - temperatures have gone up 2.5 degrees in 50 years.

Global change

Mueller, Vincent, and Jeffries say their calculations suggest changes of a similar nature have been taking place in the Ellesmere Island area.

A century ago, the entire northern coast of the island was reported to be fringed with a continuous ice shelf. About 90% of that ice area had been lost by 1982, the scientists say.

The precise timing of the break-up of the remnant Ward Hunt Ice Shelf may have been influenced by freeze-thaw cycles, wind, and tides, they tell GRL.

Other factors may include changes in Arctic Ocean temperature, salinity, and flow patterns, they add.

"Computer models show quite convincingly that global climate change would be manifested first and amplified in the polar regions and in particular in the Arctic," Dr Jeffries said

"Our observations at Ward Hunt Ice Shelf fit in with a broader picture of Arctic change which fits in with our understanding of how the Arctic climate would respond to global change."

[ICE-FLYER]

Once more the "Global Change" liars are on the march. Their arrogance is amazing. Claiming to have any idea as to the direction of the global climate is borderline psychotic.

For years I have been taking many of the worlds leading minds on the issue to Antarctica and to Greenland. Many of them do not dare suppose to speak in absolutes when it comes to such events. The fact remains, their claims of the earths age alone tells us all that their miniscule amount of collected data from RECENTLY invented devices that could accurately give them indications can not be trusted to give ANY kind of trend in one direction or another.

The current breed of world huggers who preach to us the end of the earth as we know it due to mankind are the very people who gre up worshiping the scientists who were telling us of the coming ice age in the 1970's

Anyone with an ounce of critical thinking skills would dismiss much of this garbage. I walked into a science museum in St. Louis this past summer and wanted to throw up. Their preaching to our children in absolute terms their theories that have never been proven from evolution to global climate and its massive variables that can't even be completly measured.

Frauds of the worst order and home to the socialists of the world, thats what I consider them.

[Aracelis]

Thanks for the ping.

[Truth666]

if this is not BREAKING NEWS, then what ?

[Modernman]

Refreshingly, no one is blamed. They only mention 'climate change' and warming without attributing it to SUV's

I think the scientific evidence shows that the world is getting warmer. I don't think that the evidence shows that this increase was caused by man. In the middle ages, there was a mini-ice age which was not man made. We overestimate our impact on the planet.

[-YYZ-]

The melting of floating ice will not raise levels at all. It is already displacing a mass of seawater equivalent to its total weight. When it melts it will displace the exact same amount.

As to global warming, I'm a skeptic but my mind is not closed. Some of the recent observations is the artic, with areas of perma-frost melting for the first time in recorded history, also for the first time in the oral history of the Inuit (eskimos). Maybe it's just the continuation of the end of the last great ice age, or maybe it's global warming, or perhaps it's part of some other cyclical phenomenon. As someone else said, though, if it is global warming it seems unlikely that we can do much about it now, anywya.

[ItsOurTimeNow]

After all, we know how much Republicans hate ice.

I heard they also eat babies and enjoy killing kittens!

Only Dean can save us now!!!

(LOL)

[Geritol]

when ice floats, some percentage is above the surface because liquid water expands as it freezes into solid ice. It floats because it is less dense than liquid water. Ice floats even higher in salt water because much of the salt is left behind in the seawater when the ice freezes a bit at a time (and the precipitation that adds to the ice on top has even less salt in it), and salt water is more dense than seawater.

The water displaced has the same weight as the ice, so the melted ice will take up exactly the same volume as the melted freshwater would. Because fresh water ice is less dense, it will take up slightly more space when it melts than it does as ice when the volume above the water line melts in the saltwater, but this should not affect sea levels.

It is the ice in Antarctica and on Greenland and Russia, Mongolia, Canada, Northern Europe that could measurably affect sea level if it all melted at once. Much of this ice is offshore in extended shelves and glacial mass that is suspended over the floating heighth because it is supported by the land anchorage to some slight extent, but mostly is just floating ice. It is only the ice that is totally supported by land or seabed that will affect sealevel if melted.

[Prof Engineer]

if this is not BREAKING NEWS, then what ?

It's already BROKEN, too late. Move along, nothing to see here.

[Wonder Warthog]

"...but the signs of global warming are there. It's probably too late to do anything about the changes in climate, whether natural or man-influenced."

It has ALWAYS BEEN "too late to do anything" about natural changes in climate. As a friend of mine put it "Mother Nature don't care!".

ALL (and I do mean ALL) of the scientific information indicates that the current global warming "is" a natural process, governed by cyclic changes in the luminosity of the sun, and oscillating changes in the cycles of the earth's orbit. Said process started thousands of years ago and is on-going today.

The evidence of any significant human-induced contribution to global warming is nil.

[hellinahandcart]

And we've never seen fractures like this," Dr Jeffries told the BBC.

[Our man in washington]

It's icy, it's cracked, it made it into the media because of hot air.

Can we name it the Hillary shelf?

[Chewbacca]

Naw...Hillary was the guy who climbed Mt. Everest.
Why would you want to name it after him.

:)

[Our man in washington]

So when you hear the name "Hillary" the first thing you think of is the famous mountaineer?

I envy you. You have an ability to block evil out of your mind that most men lack. May we all find such serenity. :)

[PatrickHenry]

End of the World. PING. [This ping list is for the evolution side of evolution threads, and sometimes for other science topics. FReepmail me to be added or dropped.]

[Consort]

The Solar System is passing through a warm spot in the Aether which was caused by space friction.

[Doctor Stochastic]

When I think of "Hillary," I think of Daniel Barenboim's sister-in-law.

[VRWC_minion]

Miners that ignore dead canaries in the mine soon follow.

What precisly could we do about natural changes in the Earth's climate and assuming man is responsible what can we actually do to revert the process ?

[ancient_geezer]

I think the scientific evidence shows that the world is getting warmer.

Not exactly, depends on one's time frame.

 

Ice Ages & Astronomical Causes
Brief Introduction to the History of Climate
by Richard A. Muller

Origin of the 100 kyr Glacial Cycle

Figure 1-1 Global warming

Figure 1-2 Climate of the last 2400 years

 

Figure 1-3 Climate of the last 12,000 years

Figure 1-4 Climate of the last 100,000 years

Figure 1-5 Climate for the last 420 kyr, from Vostok ice

 

I don't think that the evidence shows that this increase was caused by man. In the middle ages, there was a mini-ice age which was not man made. We overestimate our impact on the planet.

Enviro-political groups media do anyway:

 

Mankind's impact is only 0.28% of Total Greenhouse effect

" There is no dispute at all about the fact that even if punctiliously observed, (the Kyoto Protocol) would have an imperceptible effect on future temperatures -- one-twentieth of a degree by 2050. "

Dr. S. Fred Singer, atmospheric physicist
Professor Emeritus of Environmental Sciences at the University of Virginia,
and former director of the US Weather Satellite Service;
in a Sept. 10, 2001 Letter to Editor, Wall Street Journal

 

Anthropogenic (man-made) Contribution to the "Greenhouse
Effect," expressed as % of Total (water vapor INCLUDED)

Based on concentrations (ppb) adjusted for heat retention characteristics	% of All Greenhouse Gases	% Natural	% Man-made
Water vapor	95.000%	94.999%	0.001%
Carbon Dioxide (CO2)	3.618%	3.502%	0.117%
Methane (CH4)	0.360%	0.294%	0.066%
Nitrous Oxide (N2O)	0.950%	0.903%	0.047%
Misc. gases ( CFC's, etc.)	0.072%	0.025%	0.047%
Total	100.00%	99.72	0.28%

 

[js1138]

Unrelated to the topic, but it's fun to see you posting to Modernman on historical perspective.

[Alamo-Girl]

Thanks for the heads up!