Combined Arctic ice observations show decades of loss

March 3, 2015
Locations of Arctic Ocean sea ice thickness measurements from aircraft (AIR-EM and IceBridge), fixed points (other panels on the left), satellite (ICESAT) and under-ice submarines. Credit: R. Lindsay / Univ. of Washington

It's no surprise that Arctic sea ice is thinning. What is new is just how long, how steadily, and how much it has declined. University of Washington researchers compiled modern and historic measurements to get a full picture of how Arctic sea ice thickness has changed.

The results, published this month in The Cryosphere, show a thinning in the central Arctic Ocean of 65 percent between 1975 and 2012. September , when the ice cover is at a minimum, is 85 percent thinner for the same 37-year stretch.

"The ice is thinning dramatically," said lead author Ron Lindsay, a climatologist at the UW Applied Physics Laboratory. "We knew the ice was thinning, but we now have additional confirmation on how fast, and we can see that it's not slowing down."

The study helps gauge how much the climate has changed in recent decades, and helps better predict an Arctic Ocean that may soon be ice-free for parts of the year.

The project is the first to combine all the available observations of Arctic thickness. The earlier period from 1975 to 1990 relies mostly on under-ice submarines. Those records are less common since 2000, but have been replaced by a host of airborne and satellite measurements, as well as other methods for gathering data directly on or under the ice.

"A number of researchers were lamenting the fact that there were many thickness observations of sea ice, but they were scattered in different databases and were in many different formats," Lindsay said. The U.S. National Oceanic and Atmospheric Administration funded the effort to compile the various records and match them up for comparison.

Combined Arctic ice observations show decades of loss
The average annual sea ice thickness, in meters, for the central Arctic Ocean. Red dots are submarine records. The green line is the long-term trend. Credit: R. Lindsay / Univ. of Washington

The data also includes the NASA IceSat satellite that operated from 2003 to 2008, IceBridge aircraft-based measurements that NASA is conducting until its next satellite launches, long-term under-ice moored observations in the Beaufort Sea from the Woods Hole Oceanographic Institution, and other measures from aircraft and instruments anchored to the seafloor.

The older submarine records were unearthed for science by former UW professor Drew Rothrock, who used the U.S. Navy submarine measures of ice thickness to first establish the thinning of the ice pack through the 1990s. Vessels carried upward-looking sonar to measure the ice draft so they knew where they could safely surface. Further analysis of those records found a 36 percent reduction in the average thickness in the quarter century between 1975 and 2000.

"This confirms and extends that study," Lindsay said. The broader dataset and longer time frame show that what had looked like a leveling off in the late 1990s was only temporary. Instead, adding another 12 years of data almost doubles the amount of ice loss.

The observations included in the paper all have been entered in the Unified Sea Ice Thickness Climate Data Record that now includes around 50,000 monthly measurements standardized for location and time. The archive is curated by scientists at the UW Applied Physics Laboratory and stored at the U.S. National Snow and Ice Data Center.

Lindsay also is part of a UW group that produces a widely cited calculation of monthly sea-ice volume that combines weather data, sea-surface temperatures and satellite measurements of sea ice concentration to generate ice thickness maps. Critics have said those estimates of sea ice losses seemed too rapid and questioned their base in a numerical model. But the reality may be changing even faster than the calculations suggest.

"At least for the central Arctic basin, even our most drastic thinning estimate was slower than measured by these observations," said co-author Axel Schweiger, a polar scientist at the UW Applied Physics Laboratory.

The new study, he said, also helps confirm the methods that use physical processes to calculate the volume of ice each month.

"Using all these different observations that have been collected over time, it pretty much verifies the trend that we have from the model for the past 13 years, though our estimate of thinning compared to previous decades may have been a little slow," Schweiger said.

The new paper only looks at observations up to the year 2012, when the summer sea ice level reached a record low. The two years since then have had slightly more sea ice in the Arctic Ocean, but the authors say they are not surprised.

"What we see now is a little above the trend, but it's not inconsistent with it in any way," Lindsay said. "It's well within the natural variability around the long-term trend."

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33 comments

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Science Officer
1.9 / 5 (17) Mar 03, 2015
Wait a minute. Seasonal Arctic sea ice is beginning to expand and grow again? How could that happen during the "warmest year on record"?
agsb2
1.8 / 5 (16) Mar 03, 2015
Yet people have to be rescued by ICEBREAKERS where we are told it is melting!
isiyeefumis
4 / 5 (8) Mar 03, 2015
This explains the 85% rise is sea level I have read about in all the newspapers over the past 65 years. New York, Miami and all the other East Coast cities have been reporting they are moving back construction along the ocean by one or two miles. Haven't you all read about that?
antigoracle
1.9 / 5 (13) Mar 03, 2015
Wait...wait.. there is ice in the Arctic!!
Well, don't tell that to False "Profit" Al.
Next, the AGW Cult will be telling us there are still Polar bears.
runrig
4.1 / 5 (17) Mar 03, 2015
Wait a minute. Seasonal Arctic sea ice is beginning to expand and grow again? How could that happen during the "warmest year on record"?

Err, because of weather. And... go on, you can do it - figure out what the G is in AGW.
The Arctic isn't the Globe.
runrig
4.1 / 5 (14) Mar 03, 2015
Yet people have to be rescued by ICEBREAKERS where we are told it is melting!

Must have been a big ship to have been caught by Arctic ice while in Antarctic waters. Or perhaps these lying, scamming scientists who holiday aboard cruise ships in Monte Carlo harbour did'nt measure the bit the ship was floating in.
FFFingS
antigoracle
1.9 / 5 (13) Mar 03, 2015
Wait a minute. Seasonal Arctic sea ice is beginning to expand and grow again? How could that happen during the "warmest year on record"?

Err, because of weather. And... go on, you can do it - figure out what the G is in AGW.
The Arctic isn't the Globe.

So, the US isn't the globe, now the Arctic isn't the globe, soon the globe won't be the globe. You gotta admire AGW Cult "science" where if the world defies your dogma of doom and gloom, then just fabricate your own.
Ravenken
4.3 / 5 (12) Mar 03, 2015
@ScienceOfficer..you can relax with your ignorance... you won! Sit back and reap your efforts! Hope you have children!
Maggnus
4.4 / 5 (13) Mar 03, 2015
Yet people have to be rescued by ICEBREAKERS where we are told it is melting!


One can't help but laugh in the face of such obvious ignorance. Just a little bit of reading would have alerted you to the fact that the icebreaker you are talking about was caught in the Antarctic sea ice.

The amount of sea ice that grows every year around Antarctica does not come even close to the amount of ice being lost from Antarctica's ice sheets. It also does not come even close to equaling to amount of ice lost from the thinning/disappearing Arctic ice cap.
leetennant
4.6 / 5 (18) Mar 03, 2015
*sigh*. I signed up for comments just so I could respond to the inaccuracies in this section.

@scienceofficer Arctic ice extent is expanding right now because it's winter in the Northern Hemisphere. This is known as "weather". It happens every year. Overall, the extent is less in both winter and summer than it was previously and that decline is accelerating. That's what matters.

@agsbs That was the Antarctic and the ice it was investigating was exactly the same kind of fast-growing ice it got stuck in. No real irony here. The extraordinary Antarctic melt is well-documented despite increases in extent. And it's still very far away from the Arctic

@isiyeefumis You're right that sea levels are rising but Arctic ice melt is not the cause. Sea level rise is caused by thermal expansion and the melt of ice on land. Sea ice melt doesn't raise sea levels.

@antigoracle LOL. I don't even know where to start with the silly.
samohta
4 / 5 (4) Mar 03, 2015
Why isn't anyone talking about Santa and his elves? You heartless S0Bs.
runrig
4.7 / 5 (15) Mar 04, 2015
*sigh*. I signed up for comments just so I could respond to the inaccuracies in this section.

@scienceofficer Arctic ice extent is expanding right now because it's winter in the Northern Hemisphere. This is known as "weather". It happens every year. Overall, the extent is less in both winter and summer than it was previously and that decline is accelerating. That's what matters.

@agsbs That was the Antarctic and the ice it was investigating was exactly the same kind of fast-growing ice it got stuck in. No real irony here. The extraordinary Antarctic melt is well-documented despite increases in extent. And it's still very far away from the Arctic

@isiyeefumis You're right that sea levels are rising but Arctic ice melt is not the cause. Sea level rise is caused by thermal expansion and the melt of ice on land. Sea ice melt doesn't raise sea levels.

@antigoracle LOL. I don't even know where to start with the silly.

leetennant:
Good Job....
Please come back
Water_Prophet
2.3 / 5 (7) Mar 05, 2015
Is it really any surprise that with a "warming," phenomenon, or at least where heat is added to the environment, that the coldest places are the first affected?
As we all know, the climate, just assuming it IS changing, is changing slowly enough that it is difficult to observe year to year.
Heat goes from high energy to low, so there is plenty of time for released heat to flow to the poles and enact change.

What will that change be? Increased temperature? Well, a little. But the primary effect will be to melt ice.
Shootist
1.4 / 5 (10) Mar 05, 2015
Top MIT Scientist: Gov't Funded Climate Science Promotes Alarmism

Really? Do tell.

http://dailycalle...armism/?
Maggnus
4.6 / 5 (11) Mar 06, 2015
Top MIT Scientist: Gov't Funded Climate Science Promotes Alarmism


Bahahaha Richard Lindzen! Tell me shootist, do you think he is as smart as Freeman Dyson?
Maggnus
4.6 / 5 (11) Mar 06, 2015
Here's some skinny on Lindzen's claims: http://www.huffin...356.html
Returners
1.8 / 5 (6) Mar 07, 2015
"We knew the ice was thinning, but we now have additional confirmation on how fast, and we can see that it's not slowing down."


This is not entirely true, because it is unfair to talk about thickness only in the absence of considering area and volume. Volume certainly took a dive 8 to 3 years ago, but has since leveled off as well.

The negative feedbacks and the buffer of the Greenland ice cap helps prevent the ice from totally melting.
Water_Prophet
1 / 5 (8) Mar 07, 2015
Yep, as long as they don't present the very simple full picture, we are effectively being lied to.
Caliban
4.5 / 5 (11) Mar 07, 2015
Is it really any surprise that with a "warming," phenomenon, or at least where heat is added [...]Heat goes from high energy to low, so there is plenty of time for released heat to flow to the poles and enact change.

What will that change be? Increased temperature? Well, a little. But the primary effect will be to melt ice.


Aha! Again Whiffen_Poof's brilliant analysis guts like a knife through hot pudding...

You, as always, attempt to put the cart before before the horse, in order to downplay, minimize, or obfuscate the central fact, and the fact that is cause for such concern.

Sure, the poles are losing ice mass at historically unprecedented and increasing rates. And, sure this(combined with land ice melting) will have a devastating impact in terms of sea-level rise.

Still, this melting is the EFFECT of the antropogenically-driven CAUSE, aka Warming.

Without AGW, there would be no MELTING, MORON.
Caliban
4.6 / 5 (10) Mar 07, 2015
Yep, as long as they don't present the very simple full picture, we are effectively being lied to.


Then refer to my previous comment, Whiffen_Poof, and consider yourself enlightened.

Now, go forth, and tell no more lies of your own.
Water_Prophet
1 / 5 (6) Mar 07, 2015
And Caliban, we are in complete agreement, so what are you going on about? We can share moronity.
johnwbales
1 / 5 (10) Mar 07, 2015
Hopefully this trend will continue until the arctic ocean is ice-free year round. The advantages to shipping and commerce would be tremendous, not to mention how much easier it would be to extract oil and gas from the region.
Caliban
4.6 / 5 (10) Mar 07, 2015
And Caliban, we are in complete agreement, so what are you going on about? We can share moronity.


Please tell me, then, Whiffen_Poof, just how, exactly, we are "in complete agreement".

Then we can parse out how to assign shares of "moronity".
Water_Prophet
1.3 / 5 (8) Mar 08, 2015
Cali-People are responsible for melting the ice.
Caliban
4.4 / 5 (7) Mar 08, 2015
Cali-People are responsible for melting the ice.


I said _EXACTLY_, Whiffen_Poof.

A response in the general sense doesn't constitute exact agreement.

Looks like your share of "moronity" is already starting to grow.

Try again?
Water_Prophet
1 / 5 (5) Mar 08, 2015
No, no need to fight. You can have it all. You've earned it.
Time and time again.
Maggnus
4.4 / 5 (7) Mar 08, 2015
It seems like a good time to put this article here: http://www.washin...is-year/

Arctic sea ice could set an ominous new record this year: NSIDC's just released report on February's ice conditions. First, the agency notes that last month saw the third-lowest ice extent ever recorded for February, based on satellite records going back to 1979. Indeed, Arctic sea ice extent in February just keeps ticking lower and lower. "If the current pattern of below-average extent continues, Arctic sea ice extent may set a new lowest winter maximum," wrote the agency.

So much for ubamoron's continual crys of "recovery"
Mike_Massen
3.5 / 5 (6) Mar 08, 2015
Water_Prophet claimed
Is it really any surprise that with a "warming," phenomenon, or at least where heat is added to the environment, that the coldest places are the first affected?
Basic physics, u mention it now LOL - again goes to prove u don't have "4 technical degrees" !

Water_Prophet claimed
As we all know, the climate, just assuming it IS changing, is changing slowly enough that it is difficult to observe year to year.
No. we have instruments - doh !

Water_Prophet claimed
Heat goes from high energy to low, so there is plenty of time for released heat to flow to the poles and enact change
Not quite, more complex, heard of enthalpy & know how to articulate it, a uni graduate would - not U !

Water_Prophet claimed
What will that change be? Increased temperature? Well, a little. But the primary effect will be to melt ice.
No. Primary effect is obviously to warm ice & that affects structural issues Eg glaciers/ice shelves re motion...
Mike_Massen
3.4 / 5 (5) Mar 08, 2015
Maggnus offered
http://www.washingtonpost.com/news/energy-environment/wp/2015/03/05/arctic-sea-ice-could-set-an-ominous-new-record-this-year/

Arctic sea ice could set an ominous new record this year: NSIDC's just released report on February's ice conditions. First, the agency notes that last month saw the third-lowest ice extent ever recorded for February, based on satellite records going back to 1979. Indeed, Arctic sea ice extent in February just keeps ticking lower and lower. "If the current pattern of below-average extent continues, Arctic sea ice extent may set a new lowest winter maximum," wrote the agency.

So much for ubamoron's continual crys of "recovery"
Indeed !

And her trotting out so many out of date links & her so often failure to take notice of the RSS denialist warning re picking a start period re ENSO etc

Given the potentially lower albedo leading up to summer one can only wonder what dimwit spin uba could feebly offer to counter...

so sad
Water_Prophet
1 / 5 (4) Mar 08, 2015
@Cali-On second thoughts, you can share it with Mikey and Maggie, a triple crown!
It's the only fair way to do it.
But thanks for thinking of me.
Mike_Massen
4 / 5 (8) Mar 08, 2015
Water_Prophet again misses so much with non-science speak, just like a redneck who doesnt understand Sceince
@Cali-On second thoughts, you can share it with Mikey and Maggie, a triple crown!
It's the only fair way to do it.
But thanks for thinking of me.
Have you already forgotten runrig showed U the fomula for CO2's thermal resistivity.

Why can't U as a claimed uni graduate of Physical Chemistry work out the overall heat retention in Watts per square meter to compare with TSI at the Earth & directly ????????

This would be such an easy way to prove YOUR claim CO2 is a "red-herring" & "anemic" ?

You also claimed 'business' used your results or some such, just how is that possible ?

What was the rotational rate of your brass bowl ice Water_Prophet, to simulate earth ?

Why can't U answer simple Science questions Water_Prophet ?

Why can't you demonstrate proof of your claim of "4 technical degrees" ?

so sad
Caliban
4.4 / 5 (7) Mar 08, 2015
@Cali-On second thoughts, you can share it with Mikey and Maggie, a triple crown!
It's the only fair way to do it.
But thanks for thinking of me.


"On second thoughts"?

Well, Whiffen_Poof, since vague "thoughts" and generalization are all you've been able to provide in support of your notion of what exact agreement between us entails, then it is, truly, only right and proper that you accept the burden of sole and entire ownership of your "moronity".

Maggnus
4.4 / 5 (7) Mar 11, 2015
More on the lowest winter maximum ever: http://www.indepe...273.html

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