Why climate models underestimate Arctic sea ice retreat?

Oct 06, 2011
According to a recent study, the disappearance of Arctic sea ice could occur more quickly than predicted by climate models. © Lucas Girard

In recent decades, Arctic sea ice has suffered a dramatic decline that exceeds climate model predictions. The unexpected rate of ice shrinkage has now been explained by researchers at CNRS, Université Joseph Fourier and Massachusetts Institute of Technology. They argue that climate models underestimate the rate of ice thinning, which is actually about four times faster than calculations. This model bias is due to the poor representation of the sea ice southward drift out of the Arctic basin through the Fram Strait. When this mechanism was taken into account to correct the discrepancy between simulations and observations, results from the new model suggested that there will be no Arctic sea ice in summer by the end of the century. This work was published in the Journal of Geophysical Research on 29 September 2011.

The Arctic has been losing about 10% of its permanent ice layer every ten years since 1980. Melting of Arctic sea ice has also reached record heights: in mid-September 2007, at the point when sea ice reaches its annual minimum extent, perennial ice covered an area of 4.14 million km²(1). This record low level was nearly reached again in September 2011 (4.34 million km2). Climate simulations conducted for the IPCC(2) simulate the decline in Arctic sea ice resulting from global warming. They predict that summer ice will disappear altogether at the end of this century. However, when compared with 30 years of detailed satellite observations, these models appear optimistic. Arctic sea ice has thinned on average four times faster over the period 1979-2008 than in the climate simulations. True observations are therefore not correctly reproduced by these climate models, which were mainly calibrated using global variables, such as world average rather than “regional” temperature.

An explanation for this difference has been put forward by a Franco-American team, involving in particular the Laboratoire de glaciologie et géophysique de l'environnement (CNRS / Université Joseph Fourier). It may be due to a misrepresentation of the mechanical behavior of pack ice and the drift of sea ice in the models. To demonstrate this, the researchers examined the mechanisms of sea ice drift with respect to their physical state (thickness and concentration), then analyzed the model predictions in combination with field data. In 2009, these same scientists demonstrated that there had been a significant acceleration of ice drift in recent decades. This can now be explained by ice thinning, which has accelerated. Sea ice has become thinner and more fragile. Because it breaks up more easily, its mobility is increased, as is its export from the Arctic Ocean through the Fram Strait between Greenland and the Svalbard archipelago, followed by its melting. This mechanism may be exacerbating the present decline in Arctic sea ice.

The drift of sea ice is poorly described by the models, which do not take drift acceleration or southward evacuation of the ice into account. "Modeled" sea ice behaves as though it drifts freely, without any mechanical interaction between ice fragments, whatever the season, period or ice thickness. There is no link in the models between the thinning of the ice and the further acceleration of its drift.

To close this gap between simulations and observations in terms of ice thinning rates and decline, the models should take into account an acceleration of ice export through the Fram Strait. This mechanism suggests that, well before the end of the century, the Arctic Ocean will be devoid of in late summer. The disappearance of will probably occur in the next few decades, with far-reaching consequences for ecosystems, sea routes and off shore exploitation of resources.

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More information: IPCC climate models do not capture Arctic sea ice drift acceleration: Consequences in terms of projected sea ice thinning and decline, P. Rampal, J. Weiss, C. Dubois, J.M. Campin. J. Geophys. Res. 29 Septembre 2011

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Nanobanano
1.3 / 5 (3) Oct 06, 2011
This mechanism suggests that, well before the end of the century, the Arctic Ocean will be devoid of sea ice in late summer. The disappearance of Arctic sea ice will probably occur in the next few decades, with far-reaching consequences for ecosystems, sea routes and off shore exploitation of resources.


The models are "over thinking" it.

Mathematics is such that you don't even need to know the exact mechanism of transport and things like that to get a very good idea that the ice is going to be completely melted in summer very soon.

Since "real" data is the sum of all forcing, known and unknown, it doesn't matter exactly what causes the forcing: The curve is what it is.

So just fit a curve to the 5 or 10 year running average for ice extent and ice volumes, and extrapolate it.

On the optimistic end, the Arctic sea ice will be gone in the late summer or early fall of 2043.

It could be gone as early as summer of 2026.
stan_lippmann
1.3 / 5 (14) Oct 06, 2011
The entire Physics establishment is reprehensible over this phony AGW scam. Arrhenius' 1896 fraud was debunked by R. Wood at Hopkins in 1908. Richard Lindzen's 'radiative forcing' is non-physical. I imagine he made it up in a Cambridge bar on a cocktail napkin. Shame on any fool who still believes in this depopulationary eugenics scam.
emsquared
5 / 5 (5) Oct 06, 2011
The entire Physics establishment is reprehensible over this phony AGW scam. Arrhenius' 1896 fraud was debunked by R. Wood at Hopkins in 1908. Richard Lindzen's 'radiative forcing' is non-physical. I imagine he made it up in a Cambridge bar on a cocktail napkin. Shame on any fool who still believes in this depopulationary eugenics scam.

I love it when people create an account just to decry a single article.
Callippo
1 / 5 (9) Oct 06, 2011
I presented a number of indicia for geovolcanic hypothesis of global warming, induced with radioactive decay of elements in marine water and earth mantle, which is accelerated with invisible antineutrino cloud (dark matter), penetrating the solar system. Do you remember the 2012 movie, which has been labeled as the worst movie ever from scientific perspective with NASA? Maybe you should.
Truthforall
1.8 / 5 (13) Oct 06, 2011
The climate might be warming and might then cool, as was the case in the past. We do not have sufficient data to definitively say that this is man made. Further observation, study and debate are required.
Shamans in eon passed had sacrifised human to bring about rain, and change of season. To them the climate events always followed their actions/interventions and therefore the sacrifices were proven ways to control the elements. Cause and effect may not always be as they seem.
Callippo
3.6 / 5 (5) Oct 06, 2011
We do not have sufficient data to definitively say that this is man made. .
The problem is somewhat different. Most of climatic models of Arctic ice were done just with "alarmists" and yet this retreat is faster, then they expected. In some other aspects the global warming is not so fast, as they predicted - particularly with respect to global temperature as measured with satellites.

http://www.dailym...sts.html

But while the temperature of atmosphere stagnates, the temperature of oceans raises with undiminished rate. Of course, we can still explain this difference with many other factors, but we have additional indicia for such interpretation from another areas.
PinkElephant
4.3 / 5 (10) Oct 06, 2011
I presented a number of indicia for geovolcanic hypothesis of global warming
Your hypothesis is specious since it fails to account for uncharacteristic rapidity and magnitude of this climate change relative to paleoclimatic record, and the 'odd' coincidence thereof with industrialization of the world.

Furthermore, your hypothesis is manifestly incorrect, as it would lead to expectation that oceans were warming up at depth rather than at the surface -- a prediction that contradicts observations.

Lastly, your hypothesis is unnecessary since the empirically- and theoretically well grounded phenomenology of greenhouse gas-driven radiative forcing already sufficiently explains the observed changes.
emsquared
5 / 5 (3) Oct 06, 2011
I presented a number of indicia for geovolcanic hypothesis of global warming, ...

To quote Inigo Montoya: "You keep using that word. (indicia) I do not think it means what you think it means."
Nanobanano
3 / 5 (8) Oct 06, 2011
People don't understand how much geothermal energy would be required for volcanism to be causing the observed changes.

If you take the specific heat capacity of basalt, and if you assume all ~30,000 sub-oceanic volcanoes erupt as much and as often as the Hawaiian volcanoes, and for the sake of argument have it going non-stop, it is still nowhere near enough to explain the observed melting of ice or the observed warming of the oceans.

We're talking about a net loss of 100 cubic kilometers of ice in one year in the arctic "sea ice" alone, not counting net losses in other mountain glaciers and ice caps.

We're talking about SST which were, at times, as much as 5c above average over an area of as much as 20 degrees longitude by 10 degrees lattitude to a depth of a meter or more for the north-central pacific, and for the atlantic there were areas of similar size as much as 2c or 3c above normal...Considering that the "30 year normals" were just updated to reflect 2001 to 2010...
CSYGUY
5 / 5 (1) Oct 06, 2011
It is called wind. Look at the change in wind patterns and it becomes obvious. Sea ice is very fragile.
hush1
not rated yet Oct 09, 2011
And in passing...
'wind' is the adroit usage and form of 'fart'.
Poking fun.
What led to you to consider the parameter wind? Something you read?
Anda
not rated yet Oct 09, 2011
which is accelerated with invisible antineutrino cloud (dark matter).


Fascinating... You discovered what dark matter is: an invisible antineutrino cloud!
You must tell all the physics... Master...
Howhot
5 / 5 (1) Oct 11, 2011
Here is the fascinating part about Man-made global warming that comes from gasoline (gas), burning coal (lectricity), burnin oil, and gas too, and wood too. Yep here is the fascinatin part. All of that burning dumps carbon dioxide into the air and it's been building up fur years and years. Now all of da sudden liberal scientists says dat dat is green house gas and dat is going trap the hot days sun in earth just like a glass shed does keeping the crop warm all winter.

Now da earth is like the warmin shed, and all the sun light is be-in trapped, and since it's all trapped and stuff, the north poll is melting. And thing of all the drowning penguins n pool bears.

SHoot. I think dat is global warming, I noze that is true. Liberals just don't get it.

ED__269_
not rated yet Oct 14, 2011
Well said PinkElephant.

In the light of a paleoclimatic time scale, it is clear the industrial revolution has had the unexpected downside.

But our models could be better; I would like to see modeling as a entropic based function of mass balances in two vital areas (mass states of change from solids to gaseous and liquid states (manmade and the effects (such as ice drift) as well as natural) including fission and other relevant energy enterprises) AND AS A FUNCTION OF BOUNDARY TRANSITIONS to the overall planetary mass balance with respect to radiant energies.

I would also like to see someone advance that model to predict how the earths water will behave in the absence of ice.

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