Arctic's Oldest and Thickest Ice is Melting Away
Written by Fraser Cain
It's been a strange year for the Arctic. During the summer, high temperatures melted away vast regions of the Arctic sea ice, opening up the Northwest Passage for the first time. But then this winter has been unusually cold, bringing back large large areas of sea ice. So what's going on? Is the Arctic recovering, or is Global Warming marching on?
The big problem studying global warming is that the temperatures and local climate can fluctuate. Over the short term, in some regions, you can have unseasonably warm or cold temperatures. Here in Vancouver, we had one of the coldest, snowiest winters I've ever seen.
NASA scientists are measuring the long term trends for the ancient perennial sea ice that lasts across several seasons. And this ice seems to be melting away over the years. In the past, this perennial sea ice – anything that lasted more than a single year – covered 50-60% of the Arctic. This analysis was made by NASA's ICESat satellite, which measures sea ice thickness with microwaves.
This year, the perennial sea ice covered only 30% of the Arctic. And the most ancient ice, that which has survived more than 6 years, used to comprise 20% of the Arctic. Now it's down to just 6%.
As this year shows, Arctic sea ice doesn't stand still. Its coverage grows and declines seasonally, reaching the maximum in March, and the minimum in September. And this year, the maximum is up 3.9% over the previous 3 years. At the same time, the perennial sea ice coverage is down to an all-time minimum.
As the perennial sea ice thins, it's more vulnerable during the summer melt period to wind and waves. Large chunks of ice can be carried out of the Arctic to melt in warmer waters.
Don't worry about water levels rising as the sea ice coverage disappears. This ice is already in the water, displacing the same amount. So as it melts, sea levels should stay right where they are. That's different from the ice locked up in the world's glaciers, Greenland, and the Antarctic ice cap. As those melt, sea levels will rise.
To better understand the Arctic ice coverage, NASA is planning to launch a follow-on mission called ICESat II, due for launch in 2015.
Original Source: NASA News Release
Filed under: Earth Observation, Environment
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March 19th, 2008 at 8:30 pm
If perennial Arctic sea ice reached a minimum last September, and it's defined by ice older than six years, how was it supposed to increase with this winter's impressive sea ice gains?
This looks like old news repackaged as new. What up with that?
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March 20th, 2008 at 12:14 am
Maybe more glacial and other non sea-ice is melting, but why should the sea levels rise ???? Global warming means just that , and because of a warming trend there must be a greater amount of evaporation which will offset any rise in levels and then fall as rain many thousands of miles distant and in many instances just where it is needed….Who said that a trend towards a warmer planet is a bad thing ??????
March 20th, 2008 at 4:10 am
Allan: a little warming causes violent changes…
Global warming doesn't end life on Earth, but will cause plenty of suffering.
Furthermore, the melting of the Glaciers (although not this case) will rise ocean water levels afecting a lot of people (humans tend to live near the seas).
Nuno
March 20th, 2008 at 5:54 am
Oh yeah, I know 'NASA says' this and that about old ice. The AO has flipped and wind is variable.
And how about that NPR article that shows the atmosphere and the oceans cooling, but explains it with 'We just don't know where the warmth is going'. Yeah, right.
Watch Cryosphere Today for the tremendous recovery of northern and southern hemishere sea ice extent. Watch dxlc.com/solar for the quiescent sun.
We are cooling, folks. For how long, even I don't know.
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March 20th, 2008 at 6:41 am
Kim, I saw that NPR article and it left me scratching my head. With what's said in the media and by many scientists, I don't know where to go on the issue. I do believe that there is a change for all kinds of ice to be melting, but something isn't right with what's being reported.
March 20th, 2008 at 9:20 am
The article makes an unscientific assumption and somewhat misleading statement when it say "At the same time, the area of perennial ice decreased to an all-time minimum." Without written records of past artic ice coverage how does anyone know that the artic ice is at an “all-time minimumâ€. The article gives the idea that artic ocean has always had the same consistent ice coverage for which we have recoded observations. This is an assumption that cannot be proved scientifically.
Kim, interesting point about ocean cooling. The problem with global warning is the both scope of data and the length of observational time. When only the 20th century observations are included there appears to be global warming problem, but when the time frame is extended out that problem negligible.
For more incites on issues with global warming read “Environmental Effects of Increased Atmospheric Carbon Dioxide†at http://www.oism.org/pproject/review.pdf originally published in the Journal of American Physicians and Surgeons.
March 20th, 2008 at 12:43 pm
To answer a question posed above: global warming should raise sea levels through two processes: melting glaciers, adding to the total amount of water, and warming ocean water, and making virtually any substance warmer increases it's volume.
March 20th, 2008 at 12:43 pm
The warming trend's been going on for well over 10,000 years and will continue for a few thousand more. Recall that Canada was covered with ice 10,000 years ago – now it's not. Check on Malankovitch Cycles. Cold snaps do occur, but warming's been good to us so far.
March 20th, 2008 at 12:57 pm
Do not forget that Greenland was indeed green land 1000 years ago and nothing bad happened. Moreover, it happened Little Ice Age afterward.
March 20th, 2008 at 1:54 pm
Wow!! That's one of the clearest thinking threads I've ever read concerning a matter like this. Nice job all !!!
March 20th, 2008 at 3:37 pm
Say "AMEN brother!" to XLBREW. This indeed is a coherent, carefully thought out and civil response to a potentially contentious story.
I think the bottom line is that mankind just doesn't have enough data to put forth a long term forecast on "Climate Change".
March 20th, 2008 at 3:48 pm
hi Kim,
Cryosphere hasnt updated in DAYS, I bet we break 14M in the artic. it will be close.
March 20th, 2008 at 4:37 pm
In ocean water lives a lot of creatures that trappes CO2.Usually they live in cold water.If tempreture rise most will die.Means more CO2 in atmosphere a cloud of CO2 can stop sun light and cause the over heat effect.
Don't treat like a little worm is not so bad think what effect will have on 90% of creatures that live with a certain amount of CO2.
March 20th, 2008 at 4:43 pm
And about the ice ages before usually happen like an effect of old colisions (Earth with other objects), collision that changed spin of earth.Think that lv that reaches CO2 nowadays never was reached before (:D or almost never cause some say when dinosaures died was cause of an impact that reached in air tones of dust making a cloud that made impossible of sun light came and overheated the Earth)
March 20th, 2008 at 10:01 pm
My dear Nicoleta, I would like to volunteer my services as an English tutor. I THINK you may have some interesting ideas.
March 21st, 2008 at 3:38 am
Northwest passage open for first time in 2007???
Hoe about 1903, 1904, 1905 (Gjøa/Roald Amundsen) + 1940, 1941,1942 og 1944 (St. Roch).??? Please check that information..
And we came back from that "Point of no return" in no time.
Besides, OVERWHELMING EVIDENCE from eyes whitnesses and and states that the Greenland Glasiers where FURTHER BACK just 60 years ago! And we came back from this without anyone noticing a problem.
If you read danish (?!) read further down on these 2 pages… :
http://www.2waz.com/fg51/klima/indlag/grønland.pdf
http://www.2waz.com/fg51/klima/indlag/grønland1.pdf
It also states that the fish for warm waters where seen much further north thatn thet are today.
In USA: If you only pick the 5 weather stations that are furthest away from urban areas you will see that not only was 1935 the hottest year of the 20´th century but the whole period 1930.50 was warmer than today, matching very fine with the situation in Greenland in that period.
Is it a bagatel that glaciers where further back in the 1940´ties???
Anyway the people of Greenlan enjoyed that period!!!
Thanks for reading
March 21st, 2008 at 5:12 am
No matter how much we don't want to change our lifestyle – we are causing global warming. Thats a fact.
The melting of the polar caps is not a natural event. Some of this ice is a million years old – long enough for polar bears to adapt to live there.
The probability that the polar cap melts 150 years after the industrial revolution is statistically highly unlikely.
March 21st, 2008 at 9:56 am
The human factor in global warming is very small to none.
CO2 is a minor greenhouse gas when compared to water vapor and we live on a planet 70% covered with water.
Global warming does not correlate to increased use on fossil fuels. On the contrary global warming tracks solar activity and no amount of lifestyle change will change the sun. See the article on atmospheric CO2 I reference in my previously input.
March 21st, 2008 at 6:40 pm
Does anyone else see Heisenberg's uncertanty principle at work here? The satelites are beaming down microwaves (in the article) to measure ice thicknesses. Everyone knows that microwaves melt ice and heat water. The microwaves change the amount of ice as it is measuring it! OF COURSE THE ICE THICKNESS IS CHANGING!!!
September 1st, 2008 at 5:41 am
Question: my son-in-law says that the arctic was free of ice in the early 1920's. I have read or heard of nothing that suggests it has ever been free of ice in human history.
Is there any historical data to support his claim?
JB
December 31st, 2008 at 11:38 am
Western scientists are crazy. I have basically sopped listening to them on everything. There is always a different view of what they say (except on global warming – what a joke). Read this on Global Cooling:
http://denisdutton.com/newsweek_coolingworld.pdf