Arctic Sea Ice Melt 2013: Looking Forward, Looking Back
The spring equinox has now come and gone, opening the latest 'melt season' in the annual cycle of the Arctic sea ice. But this spring is different from the thousands of springs that have come and gone as humans began to settle in cities, grow crops in the country and create kingdoms and complex religious establishments. This spring follows a remarkably low fall minimum--one that has observers of the ice paying very close attention indeed. What will the record low mean for the future?
- A Love Story And A Clearance Sale
Arctic sea ice is 'far away' for most of us--but will it become 'long ago', too? There's reason to fear just that--here's why the author cares, and why more practically-minded readers should, too.
- Frequently Asked Questions on Arctic sea ice | Arctic Sea Ice News and Analysis
NSIDC FAQs index; select "What is the difference between sea ice area and extent?"
The Records--How Bad Was It?
First, just how bad was the sea-ice in 2012? Approaching the annual September minimum, we knew that, compared with the beginning of the era of satellite observation in 1979:
- The sea ice extent was down about 32%;
- The sea ice area had declined around 39%;
- The sea ice volume, shockingly, was down roughly 76%.
(For an extended discussion of the differences among these measures, see A Love Story And A Clearance Sale; for a short statement of the difference between extent and area see the NSIDC FAQs. Both are linked in the right-hand sidebar.)
But, as we now know, previous records were thoroughly eclipsed this September. An increasing number of organizations have begun to provide data on the sea ice. They include the Arctic ROOS, a European consortium; the American National Snow and Ice Data Center; the Danish Meteorological Institute; IJIS, a Japanese-American collaboration; IMS, from the US National Ice Center; MASIE, also from NSIDC; Cryosphere Today, at the University of Illinois at Urbana-Champaign; and PIOMAS, at the University of Washington.
For MASIE, CT and PIOMAS, the previous record came from 2011; in all other cases, the record was from the 'death spiral' year of 2007.
Here is a summary of 10 different measures, their previous and new records, and the percentage change the new record represents.
The smallest change is in the Arctic ROOS monthly extent record, which declined just over 9%. The largest is Cryosphere Today's daily area, where the decline was over 23%. (In general, monthly values should decline less than daily ones, and extent values less than area values.) The PIOMAS volume is down nearly 19%, which is fairly close to the various daily extent changes as well.
So: in one case, a tenth less extent than the corresponding month in 2007; in another, almost a quarter less area than the lowest day in 2011; but a sixth less or so in most measures, including the crucial measure of ice volume, PIOMAS.
It's fair to say that the previous records were decisively shattered.
To put this in a larger context, here are graphs of the evolution of extent, area, and volume over the span of the satellite era.
But what are the political and social effects of this? Are people noticing, and if so, what are they thinking? What is being said about it? Is it sparking new research?
Perhaps more importantly, what are the meteorological effects? Biological effects?
Well, people did notice. Following the record minimum, a Google search of the terms "arctic sea ice records 2012" turned up 5.9 million hits. News stories were plentiful in the print media and online, with news giants like the New York Times providing numerous articles.
On the other hand, a small survey by MediaMatters contrasted TV coverage of Arctic Sea Ice Loss with the coverage of Vice Presidential candidate Paul Ryan's workout routine. The latter was discussed 66 times on ABC, CBS, NBC, CNN, Fox News and MSNBC, while the sea ice merited just 20 mentions. On cable news, the ratio was even worse, with Ryan outpointing the Arctic 53 to 8--and of the 8 mentions, 1 (unsurprisingly, on Fox News) was misleading in that it downplayed the extent decline by conflating regional and pan-Arctic ice conditions. And only two networks, NBC and MSNBC, mentioned the connection between the ice decline and human GHG emissions.
- STUDY: TV News Covered Paul Ryan's Workout 3x More Than Record Arctic Sea Ice Loss | Research | Medi
What's important here, anyway?
This author would say that, personally and anecdotally, there is little evidence of concern, though there is some indication of increased 'background awareness.'
As the winter continued, the ice extent increased rapidly, as most observers expected--open water in the Arctic winter is still basically an invitation for ice to form--and there had been lots of open water in September. A few denialist blogs tried to paint this as a meaningful 'recovery' of the sea ice, but seemed to gain little traction.
The ice extent remains very low, but not in record territory--the National Snow and Ice Data Center reports that February saw the seventh-lowest extent in the satellite record. Lest this seem like recovery, it should be mentioned that current extent is below last year's, which was relatively high--nearly 'normal,' in fact. But that 'high' February extent didn't stop a record decline in 2012.
Arctic Warming & Circulation Links
- Evidence linking Arctic amplification to extreme weather in midlatitudes - Francis - 2012 - Geophysi
Article abstract, Francis & Vavrus, 2012.
- Barnes & Hartmann, 2012.
The text of Barnes & Hartmann. Highly technical.
- Petoukhov et al, 2013.
spacedaily.com article on Petouknov et al. Good summary for general public.
- Quasiresonant amplification of planetary waves and recent Northern Hemisphere weather extremes
Abstract of Petoukhov et al.
Quite a few science stories have emerged, which I've organized under several research theme headings.
Arctic warming and atmospheric circulation
Perhaps the most potentially significant is the question of atmospheric circulation and Arctic warming--intimately connected to sea ice extent. During late fall of 2012, Dr. Jennifer Francis of Rutgers was drawing a link between Arctic warming and changes to the polar jet stream. These changes could result in 'stuck' weather systems and thus to persistent weather conditions, raising the probability of extremes in precipitation or temperature or both.
The question was investigated by several investigators during 2012 and 2013, to results that are not yet entirely clear. So-called 'blocking events' may increase in general, or their spatial structure may change--for example, Dunn-Sigouin & Son, 2013* finds slight decreases in blocking events over the northern Atlantic and Pacific oceans, but a small increase in such events over eastern Europe and Russia. The most recent study, Petoukhov et al, 2013, find a mechanism linking warming to such extreme events as the deadly 2010 Russian heatwave.
(The mechanism is "quasi-resonance," in which, if I understand it correctly, a band of mid-latitiude 'waveguides' girdling the Northern Hemisphere can set up. These 'guides' then make a band of the atmosphere act rather like the body of a natural trumpet, in which certain frequencies can be preferentially amplified or reinforced, because they divide the instrument's length into equal segments--in this case, either six, seven, or eight.)
*Dunn-Sigouin & Son, 2013 may be accessible to interested readers at the following link:
It is slow to load, however, which makes it show up as a bad link in the Hubpages software, preventing its inclusion in the sidebar with the other papers mentioned.
- Changes in Arctic sea ice result in increasing light transmittance and absorption - Nicolaus - 2012
Nicolaus et al, 2012 abstract.
First-year ice, melt ponds, and radiation balance
Of interest in diagnosing the future evolution of the sea ice is Nicolaus et al, 2012. It considers melt pond formation over first-year Arctic sea ice. First-year ice is flatter and smoother than older, multi-year ice, and hence much more prone to the formation of a great many shallow melt ponds. Nicolaus et al sent a remote submersible under the ice to measure the light transmitted via these ponds. The result might be surprising to many.
"The young thin ice with the many melt ponds does not just permit three times as much light to pass through than older ice. It also absorbs 50 per cent more solar radiation. This conversely means that this thin ice covered by melt ponds reflects considerably fewer sun rays than the thick ice. Its reflection rate is just 37 per cent. The young ice also absorbs more solar energy, which causes more melt. The ice melts from inside out to a certain extent," says Marcel Nicolaus.
A press release describing Nicolaus et al, 2012 is accessible to interested readers at the following link:
For unknown reasons, this link is showing up as a bad link in Hubpages software, but appears to be functioning correctly nonetheless.
With the 'new Arctic' dominated by first-year ice--and more so than ever, as the 2013 melt season opens--this suggests 'a whole of melting going on.'
Sea ice, biology and ecology
A couple of studies have also connected biology with sea ice loss, either directly or indirectly.
- Massive Phytoplankton Blooms Under Arctic Sea Ice
Abstract, Arrigo et al, 2012.
- Export of Algal Biomass from the Melting Arctic Sea Ice
Abstract, Boetius et al, 2013.
Arrigo et al, 2012* showed massive phytoplankton blooms occurring under the sea ice. It is believed that the thinner ice characterizing the 'new Arctic' is facilitating such developments.
Boetius et al, 2013** shows how the the ice algae Melosira arctica, which grows on the underside of the sea ice, can affect the deep sea environment. The algae sinks quickly when the ice melts, creating patches of debris covering up to 10% of the ocean floor in affected areas, fertilizing bacterial action and creating oxygen-depleted areas--as well as sequestering carbon on the sea floor. The net effects have yet to be sorted out:
Boetius and her team warn: "We still understand far too little about the function of the Arctic ecosystem and its biodiversity and productivity, to be able to estimate the consequences of the rapid sea-ice decline."
*Arrigo et al, 2012 is described at the following link:
**Boetius et al, 2013 is described at the following link:
Atwood et al, 2013, sciencedaily story.
- Sea Ice Loss 2012: What Do The Records Mean?
Labor Day 2012 saw shocking new record lows for Arctic sea ice--and the records continued dropping. Here's the larger context, and why you should care.
Finally, an indirectly relevant study.*
Trisha Atwood, of the University of British Columbia, and her colleagues showed experimentally that the loss of top predators in an aquatic environment can indeed affect the functioning of the whole ecosystem, "all the way down to the biogeochemical level," as Ms. Atwood put it. In the study in question, the removal of top predators resulted in 93 percent more carbon dioxide being emitted into the atmosphere.
The Atwood study was directly relevant to freshwater ponds, not the marine environment of the Arctic Ocean, and notes in the abstract that the effect on emitted carbon dioxide may well depend upon the specific structure of the ecosystem's food chain(s). It nevertheless lends some support to the idea--discussed in my Hub Arctic Sea Ice Loss 2012, in which I wrote:
The sea ice is in itself a wildlife habitat. Its loss will be devastating for polar bears and seals, as well as less charismatic creatures depending on it. We cannot yet predict everything that a serious population crash of bears and seals will do, but consequences there will be.
*The abstract for Atwood et al, 2013 can be found at this link:
Yet another study addressed the question of the survival of sea-ice-dependent crustaceans called 'amphipods.' They are similar to shrimp, and their habitat is the underside of the sea ice. How, then, will they fare in a world where sea ice becomes merely seasonal?
But an international group of researchers have found that one species, at least, has a strategy to deal with ice loss: the amphipods migrate downward and ride deep ocean currents northward to recolonize any remaining ice. (The researchers dubbed this the "Nemo hypothesis," after the Disney movie in which a similar strategy was employed.) This behavior avoids export from the Arctic into the Atlantic when sea ice is 'flushed' southward via the Fram Strait. But it may also reflect the evolutionary experience of past geologic eras when sea ice was low.
J. Berge et al. Retention of ice-associated amphipods: possible consequences for an ice-free Arctic Ocean. Biology Letters, 2012.
The Science Daily story on this paper can be found here:
Update 1/11/14: Inuit Mental Health Study
- Climate change rattles mental health of Inuit in Labrador - Technology & Science - CBC News
Researchers studying the mental health and well-being of Inuit populations in coastal Labrador say rising temperatures are having damaging psychological effects on people in traditional communities. Arctic sea ice loss is a leading factor.
What will this season show?
Truly, no-one yet knows--that is the fascination of observing this Earth System tragedy as it unfolds. Although the medium-term trend is clearly that of the "death spiral" that Dr. Walt Serreze of the National Snow and Ice Data Center described, the specific weather events of each season still have a strong influence over just how the ice melt unfolds--and just how bad it gets.
Yet the 'citizen scientists' of the Arctic Sea Ice Blog--whose corporate track record is as good as anyone's these days--seem, well, guardedly pessimistic. Although sea ice extent has made its usual seasonal recovery, climbing from record low extents to seventh-lowest for the month of February, 2012 showed clearly what was already known: maximum extent does not have a strong predictive value for the subsequent ice minimum six months later. So we should not be particularly encouraged by this rise--relatively modest in any case.
Slightly more encouraging, perhaps, is the rise of the sea ice volume--after all, it's the mass of the ice to be melted that is important, and volume is directly related. According to the University of Washington PIOMAS model, the ice volume just barely crept above the 2012 value during February. But considering last year's trajectory, and the likelihood that we have reached the yearly maximum, it's a good bet that the relationship will quickly reverse once again.
But the difference is not likely to be very significant. The high proportion of first-year ice may well be more decisive.
Another portent--though a somewhat ambiguous one--is the very extensive cracking observed last month. It has been considered quite closely on the Arctic Sea Ice blog, and noted as well on the NSIDC site. Some suspect that it may enhance melting, but that remains speculative--albeit reasonable--at this point.
It's interesting, to be sure--as with so much about the sea ice situation now. What will happen?
We'll find out relatively soon--the curtain is rising on the 2013 'sea ice show.'
Appendix: Sea-ice Data Sources
Overview of Sea-Ice Data Products and Organizations
Arctic ROOS: The Arctic Regional Ocean Observing System, a consortium of "14 member institutions from nine European countries," existing to "promote, develop and maintain operational monitoring" of relevant measure of Arctic health following the end of the International Polar Year.
Their public data page: http://arctic-roos.org/observations
NSIDC: The National Snow And Ice Data Center, "part of the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado at Boulder," supported by "NASA, the National Science Foundation (NSF), the National Oceanic and Atmospheric Administration (NOAA), and other federal agencies, through competitive grants and contracts."
Their public data page: http://nsidc.org/data/
DMI: The Danish Meteorological Institute's Centre for Ocean and Ice "provides information about the state of the sea at present, and for the near future," including services such as "surge warnings, ice charting, waves, ocean currents, satellite surveyance, ocean climate and marine data."
Their English-language Arctic page: http://ocean.dmi.dk/arctic/index.uk.php
IJIS: The "IARC-JAXA Information System," a "geoinformatics facility for satellite image analysis and computational modeling/visualization" located at the "International Arctic Research Center in cooperation with the Japan Aerospace Exploration Agency (JAXA.)" (The IARC, in turn, is located at the University of Alaska Fairbanks.)
Their English language data page: http://www.ijis.iarc.uaf.edu/cgi-bin/seaice-monitor.cgi?lang=e
IMS: The "Interactive Multisensor Snow and Ice Mapping System," a program of the National Ice Center, "a tri-agency operational center, operated by the National Oceanic and Atmospheric Administration (NOAA), the United States Navy, and the United States Coast Guard." It prepares a daily ice chart intended primarily to guide marine operations of the Navy and Coast Guard, but also summary information which "can also be [used for] climatic studies."
Their data page: http://www.natice.noaa.gov/ims/
MASIE: "Multisensor Analyzed Sea Ice Extent." The NSIDC's "repackaging" of the IMS data, as discussed at the MASIE FAQ page:
An explanation in greater depth is also available here:
A 'money quote' from the latter: "MASIE gives a quick picture of ice extent that is more accurate than the daily Sea Ice Index product and allows users to compare day-to-day changes in extent values. However, in general, it would not be appropriate to compare a recent MASIE extent value to one more than a few weeks old because the data sources and analysts NIC uses may have changed. Only the data for the most recent four weeks is maintained as publicly available.
CT: "Cryosphere Today" is the website of the Polar Research Group within the Department of Atmospheric Studies at the University of Illinois at Urbana-Champaign. Their data is obtained from NSIDC, but they make area--rather than extent--numbers publicly available.
PIOMAS: The "Pan-Arctic Ice Ocean Modeling and Assimilation System," a project of the "Polar Science Center", "a department with the Applied Physics Laboratory at the University of Washington." PIOMAS has been the only publically-available near-real time information on sea ice volume. Strictly speaking, it should probably not be called 'data,' since it is based upon a "reanalysis"--that is, modeled, rather than directly observed, ice thickness.
The model does, however, "assimilate" available relevant data on an ongoing basis. Recently released analysis of satellite data from the new Cryosat 2 program strongly suggests that PIOMAS is modeling sea ice accurately. And for volume, it is still the "only game in town."
The PIOMAS page: http://psc.apl.washington.edu/wordpress/research/projects/arctic-sea-ice-volume-anomaly/
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We depend upon the 'fire' of solar radiation for our very lives. But how intense is this fire? Does it change? Here's the story of these questions and their answers--and of the people investigating them.
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