by Natasha Vizcarra
On the prowl for food, Adelie penguins scan the ice ceiling. They peck at silverfish and hunt for polynyas, gaping holes in the sea ice where shoals of krill and bug-like copepods graze on clouds of algae. When spring comes, the huge plates of sea ice start to melt and later in the brief Antarctic summer all but disappear. Then, algae blooms unfurl: a bacchanalian feast for krill and critters all the way up the Antarctic food chain. Sea ice, sunlight, and food—they all come and go with the seasons in the Southern Ocean.
Paul Holland, a climate modeler with the British Antarctic Survey, has spent the last ten years studying Antarctica’s sea ice and the Southern Ocean. Lately, he has been scrutinizing the seasons of Antarctica and how fast the ice comes and goes. Holland thinks these seasons may be a key to a conundrum: If Earth’s temperatures are getting warmer and sea ice in the Arctic has been shrinking fast, why then is sea ice in the Antarctic slowly increasing?
Opposite poles
Sea ice is simply frozen seawater. Although found only in the Arctic and the Antarctic, it influences Earth’s climate in big ways. Its bright surface reflects sunlight back into space. Icy areas absorb less solar energy and remain relatively cool. When temperatures warm over time and more sea ice melts, fewer bright surfaces reflect sunlight back into space. The ice and exposed seawater absorb more solar energy and this causes more melting and more warming.
Scientists have been watching this feedback loop of warming and melting in the Arctic. To them, Arctic sea ice is a reliable indicator of a changing global climate. They pay the most attention in September when Arctic sea ice shrinks to its smallest extent each year. Measured by satellites since 1979, this minimum extent has been decreasing by as much as 13.7 percent per decade. Antarctic sea ice, on the other hand, has not been considered a climate change indicator. Whereas Arctic sea ice mostly sits in the middle of land-locked ocean—which is more sensitive to sunlight and warming air—Antarctic sea ice surrounds land and is constantly exposed to high winds and waves.
According to climate models, rising global temperatures should cause sea ice in both regions to shrink. But observations show that ice extent in the Arctic has shrunk faster than models predicted, and in the Antarctic it has been growing slightly. Researchers are looking much closer at Antarctica, saying, “Wait, what is going on down there?” Holland is one of those intrigued.
“The Antarctic case is as interesting as the Arctic case,” Holland said. “You can’t understand one without understanding the other.”
Minding the models
To Holland, the discrepancy calls parts of the climate models into question. Modeling groups from around the world collaborate on the Coupled Model Intercomparison Project Phase 5 (CMIP5), which simulates Earth’s climate and predicts how it will change in the near future. World leaders and policy makers rely on it to decide how much countries should limit carbon emissions, known to cause some aspects of climate change.
“Almost all of the CMIP5 models produce a decrease in Antarctic sea ice,” Holland said. “There is a problem in the bit that reproduces the last 30 years of sea ice variability.” Holland was searching for data to improve and verify his own modeling of trends in Antarctic ice when he noticed that other researchers were finding that the trends varied in strength in the different seasons.
Most studies on Antarctic sea ice trends focus on changes in ice extent. For Holland, it was more important to look at how fast the ice was growing or shrinking from season to season. “Changes in climate forcing directly affect the rate of ice growth,” he said, “not the amount of ice.” Year to year cooling in autumn, for example, may cause faster ice growth during autumn, but not necessarily an increase in the amount of autumn ice.
Spring surprise
Holland used data from NASA’s National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) to calculate the ice concentration rate of growth for each single day, which he called intensification; and the total ice area rate of growth, which he called expansion. “I did that for all thirty years of data and plotted the trends,” he said. Holland’s plots showed that the different regions in the Southern Ocean contributed to the overall increase, but they had very diverse trends in sea ice growth. This suggested that geography and different wind patterns played a role. So to gain more insight Holland looked at seasonal wind trends for the different regions.
Holland found that winds were spreading sea ice out in some regions and compressing or keeping it intact in others and that these effects began in the spring. It contradicted a previous study in which, using ice drift data, Holland and Ron Kwok from the NASA’s Jet Propulsion Laboratory (JPL) found that increasing northward winds during the autumn caused the variations.
“I always thought, and as far as I can tell everyone else thought, that the biggest changes must be in autumn,” Holland said. “But the big result for me now is we need to look at spring. The trend is bigger in the autumn, but it seems to be created in spring.”
“Paul has created two more sea ice metrics that we can use to assess how Antarctic sea ice is responding,” said researcher Sharon Stammerjohn, referring to the measures of intensification and expansion. The new metrics help assess how the system is responding as opposed to simply monitoring the state of the system. “Say your temperature is at 99.2 degrees Fahrenheit,” Stammerjohn said. “You don’t have any insight to that temperature unless you take it again an hour later and you see that it changed to 101 degrees. Then you can say, okay, my system is responding to something.”
Partial explanations
Holland continues to study the Antarctic spring to better understand why Antarctic sea ice is changing. While Holland’s work helps researchers begin to see the problem in more detail, scientists continue to develop ideas about why the ice is expanding.
One study paradoxically suggests that ocean warming and enhanced melting of the Antarctic ice sheet is causing the small but statistically significant sea ice expansion in the region. Another study suggests that rain caused by a warmer climate has been causing an influx of fresh water into the Southern Ocean, making it less dense and inhibiting oceanic heat from reaching sea ice in the Antarctic. To date, there is no consensus on the reason for the expansion.
“Partial explanations have been offered, but we don’t have the complete picture,” said Ted Scambos, a scientist at NSIDC DAAC. “This may just be a case of ‘we don’t know yet.’”
References
Bintanja, R., G. J. Van Oldenborgh, S. S. Drijfhout, B. Wouters, and C. A. Katsman. 2013. Important role for ocean warming and increased ice-shelf melt in Antarctic sea-ice expansion. Nature Geoscience 6: 376–379, doi:10.1038/ngeo1767.
Cavalieri, D. J., C. L. Parkinson, P. Gloersen, and H. Zwally. 1996, updated yearly. Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data. Southern Hemisphere. Boulder, Colorado USA: NASA National Snow and Ice Data Center (NSIDC) DAAC.
Holland, P. R. 2014. The seasonality of Antarctic sea ice trends. Geophysical Research Letters 41, doi:10.1002/2014GL060172.
Holland, P. R. and Kwok, R. 2012. Wind driven trends in Antarctic sea-ice drift. Nature Geoscience 5: 872–875, doi:10.1038/ngeo1627.
Holland, P. R., N Bruneau, C. Enright, M. Losch, N. T. Kurtz, R. Kwok. 2014. Modeled trends in Antarctic sea ice thickness. Journal of Climate 27: 3,784–3,801, doi:10.1175/JCLI-D-13-00301.1.
Kirkman, C. H., C. M. Bitz. 2011. The effect of the sea ice freshwater flux on Southern Ocean temperatures in CCSM3: Deep-ocean warming and delayed surface warming. Journal of Climate 24: 2,224–2,237, doi:10.1175/2010JCLI3625.1.
Scambos, T. A., R. Ross, T. Haran, R. Bauer, and D.G. Ainley. 2013. A camera and multisensor automated station design for polar physical and biological systems monitoring: AMIGOS. Journal of Glaciology 59(214): 303–314, doi:10.3189/2013JoG12J170.
Stammerjohn, S., R. Massom, D. Rind, and D. Martinson. 2012. Regions of rapid sea ice change: An interhemispheric seasonal comparison. Geophysical Research Letters 39, L06501, doi:10.1029/2012GL050874.
For more information
NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC)
| About the remote sensing data | |
| Satellites | Nimbus 7 and Defense Meteorological Satellite Program (DMSP) F8, F11, F13, F17 |
| Sensors | Scanning Multichannel Microwave Radiometer (SMMR), Special Sensor Microwave/Imager (SSM/I), Special Sensor Microwave Imager/Sounder (SSMIS) |
| Data set | Sea ice concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data |
| Resolution | 25 kilometers |
| Parameter | Sea ice concentration |
| DAAC | NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) |
The photograph in the title graphic shows sea ice in the Bellingshausen Sea, off the coast of Antarctica, as seen from a NASA Operation IceBridge flight on October 13, 2012. (Courtesy M. Studinger/NASA)
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“Its bright surface reflects sunlight back into space. Icy areas absorb less solar energy and remain relatively cool. When temperatures warm over time and more sea ice melts, fewer bright surfaces reflect sunlight back into space. The ice and exposed seawater absorb more solar energy and this causes more melting and more warming.”
Once again, an assertion made by NASA without even a citation to support it. As I’ve argued before, the claim overstates the difference between the reflectivity of snow/ice and sea water at high latitudes.
https://wattsupwiththat.com/2016/09/12/why-albedo-is-the-wrong-measure-of-reflectivity-for-modeling-climate/
The only explanation for growth in Antarctic ice is one that is consistent with prevailing theories of global warming.
Or it could be that Svensmark’s theory applies to the Southern Hemisphere where there are very few humans to add sulfuric acid to the atmosphere and where most of the cloud condensation nuclei form from biological aerosols, the kind predicted by CERN to be enhanced by galactic cosmic rays.
“shrunk faster than models predicted”?
Really? Over two decades of repeated predictions that that Arctic sea ice was going to all melt?
Along with predicted concurrent dooms for animals they claim are dependent upon sea ice?
Easy to write this kind of alleged articles.
A) Rewrite history to establish a red herring lie.
B) Claim to provide a correction to the red herring.
Never mind that Antarctica has refused to melt according to climate modeler and climate alarmist predictions.
Tripe, pure tripe.
Ah but, its rotten ice. Nothing to see here, move along!
“Scientists have been watching this feedback loop of warming and melting in the Arctic. To them, Arctic sea ice is a reliable indicator of a changing global climate.”
It’s a negative feedback to weaker solar wind states since 1995. While a net increase in climate forcing cools the AMO and Arctic, but the Antarctic warms. That’s the polar see-saw effect. AMO and Arctic warming is normal at least during each centennial solar minimum.
“This suggested that geography and different wind patterns played a role.”
I’m shocked, I tell you. Shocked!
The entire effort to model polar ice is doomed to failure because they can only see it through one lens: it’s all due to AGW plus a bit of noise. They “know” the answer before they ask the question.
The models failed to predict the rapid decline from 1997-2007: because it was not caused by CO2.
They then tweaked their models to produce more melting by arbitrary fiddling with feedbacks and parameters. When arctic ice bottomed out in 2012 and recovered to 2007 levels by 2019 they totally failed capture that too: because they only have one hammer and see everything as a nail.
The fact that the Antarctic showed an increase over the same period, totally contrary to what their models predicted shows that they have zero skill in modelling the real world.
But that does not matter because they are not doing science they are playing politics. Something at which they are equally unskilled but their hubris allows them to consider that their cloistered space in academia, protected from the realities of life, somehow makes them qualified to dictate global politics and energy policy.
The fabled albedo feedback is clearly not a dominant factor in the Arctic, despite it always being wheeled out as the OMG argument.
There is little sunlight in the Arctic, NONE for much of the year. What there is is glazing incidence and mostly reflected. This is countered by more heat loss from open water ( no insulating ice layer ) ; increased evaporation and increased IR heat loss all year round.
The idea of run away melting was consistent with the data over the limited period 1978-2012. However, it is totally inconsistent with the following decade. Once you have a positive feedback, the “falling vase” cannot slow and back up a bit.
The albedo feedback, run away melting, tipping point hypothesis is DEAD.
Now apply that admission the the rest of climate pseudo-science.
Some of you might be interested in this graph:
1) it is getting cooler in the antarctic
2) there is very little warming in the SH (when measured on the ground)
3) there is demonstrative warming in the NH
4) there is extra ordinary warming in the arctic.
Click on my name to read my report
<em>‘Antarctic sea ice, on the other hand, has not been considered a climate change indicator.’ </em>
OK a cold ‘snap’ is weather; heatwaves indicate climate change.
Maybe that is why the HadCRUT ‘data’ product now has more Arctic data in it and very little Antarctic data?
So just to make sure we’ve got it correct, they’re unsure of the nature of the build-up and loss of polar ice but either way ‘settled science’ says it’s humanity’s fault!
All of it is just more Politics and less science.
NSIDC for the arctic. Month of March, max extent.
2015 14.51 Million square kilometers.
2016 14.52
1017 14.42
2018 14.48
2019 14.78
2020 15.05
I would suggest that Antarctic sea ice increase is caused by sea surface temperature decrease, or rather that both have the same cause.
This may help Paul Holland – it is certainly a very interesting temperature pattern –
https://wattsupwiththat.com/2019/04/10/the-curious-case-of-the-southern-ocean-and-the-peer-reviewed-journal/