by Jane George, Nunatsiaq News, May 23, 2008
Has melt reached tipping point where retreat cannot be halted?
Here's the good news: this summer's Arctic ice melt means an early start to the Hudson Bay shipping season.Forecasts show Coast Guard icebreakers will no longer be necessary for shipping to Churchill after July 16.
This figure shows probable ice conditions in Hudson Bay in July. The dark area in the centre indicates below-normal ice conditions. Ice experts predict the shipping season in Hudson Bay may open two weeks earlier than normal this year. (COURTESY OF THE NATIONAL SNOW AND ICE DATA CENTER)
That's 15 days earlier than the average ice-free shipping date of July 31, which means re-supply barges should able to reach communities in Nunavut's Kivalliq and Kitikmeot regions that much earlier.
But the down side to the retreat of the Arctic's thin ice cover is a 50-50 chance that the North Pole will become ice-free this September - for the first time in more than 100,000 years.
"The North Pole is where there's supposed to be ice," said environmental scientist Mark Serreze in a recent telephone interview from the U.S. National Snow and Ice Data Center in Colorado.
Scientists like Serreze say the weakness of the ice that's melting is responsible for the retreat of Arctic sea ice.
As old ice melts, a development linked to rising water and air temperatures, the new, thin ice that forms in its place in the winter tends to melt much more rapidly in the spring and summer.
During the month of April, scientists determined that the Arctic's increasingly flimsy sea ice cover shrank by 6,000 square kilometres every day.
If this ice continues to melt at the same rate as in 2007, scientists predict that only 2.22 million sq km of ice - less than the size of Nunavut - will remain in the Arctic Ocean this September. This would be much less than the record low of 4.28 million sq km set in 2007.
A major concern is whether the Arctic ice melt has reached a "tipping point," where even tough measures to curb global warming won't stop its final retreat.
After this tipping point is reached, the Arctic Ocean is expected to settle into an ice-free state every summer.
Tipping points were the hot topic at last week's Arctic Forum conference in Washington, D.C., where scientists looked at the potential consequences of these "points of no return" on the environment and people.
The impact of tipping points may explain why the Norse in Greenland died out during the 1400s.
The Norse settlers were unable to deal with several changes occurring at the same time, suggested researcher Tom McGovern in his talk, "Well adapted but still extinct: Norse Greenland in new perspective."
Today's sea ice loss is expected to deliver many environmental changes, which will compound other social, economic and political stresses in the circumpolar world.
New scientific information about Arctic sea ice loss played into last week's decision by the United States Fish and Wildlife Service to list polar bears as "threatened."
Scientists expect that as sea ice thins, melts and retreats, open water will allow even more heat to enter the Arctic Ocean. This warmer ocean will in turn heat the land and melt glaciers where they flow into the water.
As Greenland's ice sheet melts, sea levels may rise, threatening many coastal, low-lying communities.
The stream of icebergs, recently seen off Newfoundland and Labrador, originate from glaciers in Greenland. Scientists suspect these icebergs reflect the breakdown of the island's huge ice sheet, which is occurring many times faster than scientists believed possible.
Over the short term, an ice-free Arctic Ocean will open up new possibilities, including easier access to natural resources and new transportation routes.
The Northern sea route, the shipping lane from the Atlantic Ocean to the Pacific Ocean along the Siberian coast, is expected to open up this summer, and the Northwest Passage through Nunavut waters is also likely to be navigable by August.
Link to article: http://www.nunatsiaq.com/archives/2008/805/80523/news/climate/80523_1219.html
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4 comments:
In the article ’North Pole could be ice free’ at NewScientist.com 25 April 2008 ( http://environment.newscientist.com/channel/earth/dn13779-north-pole-could-be-ice-free-in-2008.html ) it says:
“Despite its news value in the media, the North Pole being ice free is not in itself significant. To scientists, Serreze points out, "this is just another point on the globe””
And here it says:
“"The North Pole is where there's supposed to be ice," said environmental scientist Mark Serreze in a recent telephone interview from the U.S. National Snow and Ice Data Center in Colorado.”
I think Mark Serreze has been reading the comments at newscientist.com, because there I read this:
By Korhan
Fri Apr 25 23:05:39 BST 2008
I am pretty sure some people just can't wait for this to happen so they can raise funds for an expedition to go and have a few strokes in the north pole in the name of drawing attention and raising money for polar research of course. One wouldn't know whether to applaud them or chase with a stick.
And what kind of a comment is "this is just another point on the globe". It's not just another point, its THE north pole. It is supposed to be covered with ice.
And it is indeed not just a point on the globe! With an ice free North Pole the Arctic will have more heat absorbing sea water. Water evaporates and H2O is the biggest greenhouse gas. The water will become much warmer. Warmer water holds less CO2, expends and is les able to hold back Greenland’s ice sheets than the sea ice is doing now… And than there are the permafrost and methane hydrates which lock away methane reserves which are able to warm the earth with a lot of degrees. (There are already signs of big methane releases around the Arctic http://www.spiegel.de/international/world/0,1518,547976,00.html )
It seems to be to much of wishful thinking to hope everything will be able to go back to normal…
Dear Leon,
Nice to see you back again!
Yes, it would be just wishful thinking to dream that things will go back to "normal," sad to say.
Mark Serreze is often quoted, but between you and me, I don't know why.
If you look a few posts down, you will see more on this subject of the Arctic.
Today, I also put a personal post about the fast retreating snow cover on the southwest coast of Greenland -- normally, I don't write the posts, as I am sure you have realized.
I check your website almost every day. It's great to have someone who collects a lot of stuff I'm really interested in!
And about Greenland; it has indeed been very warm there for last month: http://www.cpc.noaa.gov/products/intraseasonal/z500_nh_anim.shtml
Wow, Leon! That was some link! Now, I have to learn to understand what I am seeing.
I just sent an e-mail to the NSIDC to ask them if they would please update the Arctic Sea Ice Extent Graph -- it is 25 days out of date. I am fairly sure that the sea ice is now below what it was at this time in 2007.
Have you seen this site:
http://www.cira.colostate.edu/cira/RAMM//rmsdsol/tropical.html
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