Early results from the European Space Agency’s Cryosat-2 satellite, launched in 2010, suggest that the Arctic sea ice volume in summer is currently being lost at the rate of 900 cubic kilometres per year, Robin McKie reports in The Guardian. By combining Cryosat data with other sources they have concluded that there has been a dramatic reduction in sea ice volume over the last eight years:
In winter 2004, the volume of sea ice in the central Arctic was approximately 17,000 cubic kilometres. This winter it was 14,000, according to CryoSat.
However, the summer figures provide the real shock. In 2004 there was about 13,000 cubic kilometres of sea ice in the Arctic. In 2012, there is 7,000 cubic kilometres, almost half the figure eight years ago. If the current annual loss of around 900 cubic kilometres continues, summer ice coverage could disappear in about a decade in the Arctic.
Ten years (or less) ’til its gone in summer. I hate to say I told you so, but…
Until Cryosat data came along, the only comprehensive source of information on sea ice volume was the PIOMAS modelling done at the University of Washington. The last time I looked at PIOMAS numbers, back in 2010, they showed an annual reduction of 780 km3 in the mean volume of sea ice at minimum in September. I’m not sure how the Cryosat and PIOMAS numbers will stack up against each other, but the Guardian report suggests that they are telling the same story. And that’s not a good thing, as McKie points out:
The consequences of losing the Arctic’s ice coverage, even for only part of the year, could be profound. Without the cap’s white brilliance to reflect sunlight back into space, the region will heat up even more than at present. As a result, ocean temperatures will rise and methane deposits on the ocean floor could melt, evaporate and bubble into the atmosphere. Scientists have recently reported evidence that methane plumes are now appearing in many areas. Methane is a particularly powerful greenhouse gas and rising levels of it in the atmosphere are only likely to accelerate global warming. And with the disappearance of sea ice around the shores of Greenland, its glaciers could melt faster and raise sea levels even more rapidly than at present.
This summer in Greenland has already been extraordinary, but ice melt is likely to go further into overdrive if the entire ice sheet is surrounded by rapidly warming oceans. I suspect that a lot of assumptions about what sorts of melt rates are feasible are going to have to be reviewed — and in the wrong direction.
Professor Chris Rapley of UCL said: “With the temperature gradient between the Arctic and equator dropping, as is happening now, it is also possible that the jet stream in the upper atmosphere could become more unstable. That could mean increasing volatility in weather in lower latitudes, similar to that experienced this year.”
Rapley’s point is key. The continuing loss of sea ice cover on the Arctic Ocean is already affecting northern hemisphere weather patterns1. The loss of sea ice is therefore driving changes in climate throughout the northern mid-latitudes. Climate change is no longer an abstract concept for future generations to worry about. It’s real, it’s here and it’s happening now.
[See also: Arctic Sea Ice blog, and for what might happen to winter ice, my thoughts from 2010.]
[MARRS]
Truly, this is no longer the planet I was born on.
Indeed, Bill. We may be looking at a not too distant future as different from today, as the ice age is from today, only hot, instead of cold. All in a human lifetime or two.
In fact, reading his article made me think of that, and that it might be a good way of pointing out to people how serious this is.
If we’re unlucky, my lifetime will span the transition to a hothouse planet. My gut feeling says that the loss of summer sea ice makes the loss of winter ice inevitable, and that will radically transform the climate of the planet – possibly within 25 years… (Check out my thoughts here: at 900 km3 loss per year, the gap from summer ice loss to winter ice loss is down to 22 years).
To me ice free Septembers look likely within a dozen years or so, and it seems likely that when that happens, the weather patterns through Sept – Nov in the north of the Northern Hemisphere will be significantly affected, including an acceleration of Greenland ice loss. Truly ice free Arctic winters before late century though seem unlikely to me, the ice will appear when the sea surface temperatures drop below freezing (as it does now), and in the northern Arctic latitudes temperatures are already dropping below zero, within two months they’ll be approaching -25C, that’s a big temperature drop that has to disappear before ice free Arctic winters.
I think you can make a case for anything between 3 and 15 years for the Sept minimum to fall below some threshold equivalent to “ice free” (for me, that would be 1m km^2 – not much more than a rump of ice clinging to the Canadian archipelago). Over the next year or two Cryosat will give us a much more nuanced picture of volume behaviour, and that will help to refine that sort of projection. However, anything over 15 years is beginning to look like wishful thinking.
On the winter ice, you need to think in terms of the heat budget, not just temperature. The latent heat of fusion is the key factor. 900 km^3 of ice represents a lot of heat input excess over winter cooling.
On the winter ice, you need to think in terms of the heat budget, not just temperature. The latent heat of fusion is the key factor. 900 km^3 of ice represents a lot of heat input excess over winter cooling.
900 km^3 spread over 9 million km^2 is an ice thickness of 4″. Around here in the winter we can get most of that in one night.
The insulating effect of the ice vs open water is a super key factor, the ocean surface will cool quickly going into winter until the ice forms, after the ice cover has formed the rate of surface cooling will drop. So we’ll see a delay in initial ice formation, but it’ll still happen surprisingly quick.
Only at first. The annual heat “surplus” isn’t simply going to stop — if anything it will carry on increasing as the planet gets further out of thermal equilibrium. There is going to be more and more heat accumulating in the ocean over summer that has to be lost in the autumn. Eventually that will exceed the cooling, and we’ll have an ice free Arctic Ocean year round. We can argue about how fast, but it will happen — and it might happen within the 30 year climate commitment that’s already locked in.
Ice free Arctic winters are an interesting debating topic. I am with Andrew on the idea that a relatively thin surface ice layer would form rather quickly once the Sun retreats from the Arctic and then through its insulation effect slows the further cooling of the underlying waters. I guess it will from there depend on the effects of the ocean heat content and convective behavior under the ice to see if it would grow in thickness over winter and also on precipitation (snow) from above. Somehow I can’t think that during the sun-less arctic winter the surface waters would not freeze. They do today even in much lower latitudes and with much warmer oceans that have only short winter freeze periods. It does need calm weather though, stormy conditions hinder ice formation of cause.
I have once been stuck on a Danish island in the late 80ies for over a week due to a -25C cold spell freezing the Baltic ocean there quickly to a thickness well beyond the capability of the otherwise well equipped ferries designed to break ice up to a certain thickness. There was floating ice around before already of cause. And the Baltic is an ocean that can often be at over 20C during summer. Hard to see how that sort of freezing would not befall the Arctic for a long time to come during the sun-less winter months. But I am open minded to see any good paper claiming the opposite.
There was a recent rescue of sailors trapped in the Baltic due to sea ice encroachment. By recent I mean last 2 years.
I can dig out links if you want.
.
Of course, if someone puts a match to all that methane bubbling out, it could be a whole different ballgame.
Sonny
(with only a slight tongue-in-cheek nod to Gareth’s new Burning World Series, The Aviator ;))
However the ice numbers eventually crunch out, this theatre review article that just appeared in the Hot Tweets seems apt.
thanks for this, if anyone is interested, there’s a JBowers @
12 August 2012 1:46AM, who has replied to a couple of denial-a-loon comments, with some very strong information on CO2 effects on plant life, conflict etc. well worth reading, if a little dismal.
But is this really so extraordinary ?
Arctic ice all but melted in 1958 when this photo was taken – of USS Skate – surfaced at the North Pole.
http://www.navalhistory.org/2011/08/11/uss-skate-ssn-578-becomes-the-first-submarine-to-surface-at-the-north-pole/
See my previous post. I’d say you’re running the “it’s happened before” line, but rather poorly.
And read the comments under the article you link to.
so u have evidence that the decadal melt in 1958 was 9000 cubic kilometers..
from one photo
Idiot
God, not the bloody USS Skate! As Gareth says, do the reading…
Skating on thin ice again mate 😉
bennydale, that article does not claim the ‘Arctic ice had all but melted’. What it said was that the submarine found a lead (of thin ice or open sea) at the North Pole. Quote: “The submarine’s black hull stood out in stark relief against the deep blue of the calm lake in which the ship now floated. Beyond the lake, stretching to the horizon in every direction, was the stark white of the permanent polar ice pack.”
It’s amazing really, how they just managed to find a hole in the North Pole to poke their submarine through.
What are the chances of that?
Read bennydale’s link, and the comments underneath. Sea ice is prone to forming cracks (“leads”) at all times of year.
What’s hard to comprehend in the following, andy? –
Oh, I forget, you’re into preconceptual science.
There are at least two problems with any photo of the submarine, USS Skate, surfacing at the North Pole on MARCH 17, 1959.
First, on MARCH 17th, it is still twilight at the North Pole as can be verified at the ATHROPOLIS Guide to Arctic Sunrise and Sunset. The polar night is 6 months long right at the geographic pole. The Sun doesn’t breech the horizon there until the vernal (Spring) equinox, which in 1959 was March 21 at 03:55a Eastern Standard Time. Yet, the picture clearly shows Skate bathed in diffuse daylight on a cloudy day with the sun high in the sky. So, this picture was not taken at the North Pole on March 17, 1959 but was most likely taken further south. And, the question of year, 1958/1959/etc has to be verified by examining the foredeck of the USS Skate which underwent minor modification through its service life. Doubtless there will be photos of submarines bathed in sunlight at the North Pole in the months of May through to August when the sun doesn’t set.
Second, March is the time of the greatest thickness and extent of sea ice during the annual cycle. For there to be little or no sea ice at the North Pole in March, it would mean that there was little or no sea ice all year round that year, which is . That the USS Skate had to break through ice is confirmed by checking out “Surface at the Pole”, the story of USS Skate by Commander James Calvert, USN. Hutchinson & Co -1961. On pages 182 -183 of his book, Calvert wrote:
“…the permanent polar ice pack”
Or so it seemed at the time!