The Arctic Death Spiral Continues: Thick, Multi-Year Sea Ice Melting Faster, NASA Study Finds

The average thickness of the Arctic sea ice cover is declining because it is rapidly losing its thick component, the multi-year ice. At the same time, the surface temperature in the Arctic is going up, which results in a shorter ice-forming season,” explains NASA senior scientist Joey Comiso.

The bright white central mass shows the perennial sea ice while the larger light blue area shows the full extent of the winter sea ice including the average annual sea ice during the months of November, December and January. Credit: NASA

— A NASA News Release

GREENBELT, Md. — A new NASA study revealed that the oldest and thickest Arctic sea ice is disappearing at a faster rate than the younger and thinner ice at the edges of the Arctic Ocean’s floating ice cap.

The thicker ice, known as multi-year ice, survives through the cyclical summer melt season, when young ice that has formed over winter just as quickly melts again. The rapid disappearance of older ice makes Arctic sea ice even more vulnerable to further decline in the summer, said Joey Comiso, senior scientist at NASA Goddard Space Flight Center, Greenbelt, Md., and author of the study, which was recently published in Journal of Climate.

The new research takes a closer look at how multi-year ice, ice that has made it through at least two summers, has diminished with each passing winter over the last three decades. Multi-year ice “extent” – which includes all areas of the Arctic Ocean where multi-year ice covers at least 15 percent of the ocean surface – is diminishing at a rate of -15.1 percent per decade, the study found.

There’s another measurement that allows researchers to analyze how the ice cap evolves: multi-year ice “area,” which discards areas of open water among ice floes and focuses exclusively on the regions of the Arctic Ocean that are completely covered by multi-year ice. Sea ice area is always smaller than sea ice extent, and it gives scientists the information needed to estimate the total volume of ice in the Arctic Ocean. Comiso found that multi-year ice area is shrinking even faster than multi-year ice extent, by -17.2 percent per decade.

“The average thickness of the Arctic sea ice cover is declining because it is rapidly losing its thick component, the multi-year ice. At the same time, the surface temperature in the Arctic is going up, which results in a shorter ice-forming season,” Comiso said. “It would take a persistent cold spell for most multi-year sea ice and other ice types to grow thick enough in the winter to survive the summer melt season and reverse the trend.”

Scientists differentiate multi-year ice from both seasonal ice, which comes and goes each year, and “perennial” ice, defined as all ice that has survived at least one summer. In other words: all multi-year ice is perennial ice, but not all perennial ice is multi-year ice (it can also be second-year ice).

Comiso found that perennial ice extent is shrinking at a rate of -12.2 percent per decade, while its area is declining at a rate of -13.5 percent per decade. These numbers indicate that the thickest ice, multiyear-ice, is declining faster than the other perennial ice that surrounds it.

As perennial ice retreated in the last three decades, it opened up new areas of the Arctic Ocean that could then be covered by seasonal ice in the winter. A larger volume of younger ice meant that a larger portion of it made it through the summer and was available to form second-year ice. This is likely the reason why the perennial ice cover, which includes second year ice, is not declining as rapidly as the multiyear ice cover, Comiso said.

Multi-year sea ice hit its record minimum extent in the winter of 2008. That is when it was reduced to about 55 percent of its average extent since the late 1970s, when satellite measurements of the ice cap began. Multi-year sea ice then recovered slightly in the three following years, ultimately reaching an extent 34 percent larger than in 2008, but it dipped again in winter of 2012, to its second lowest extent ever.

For this study, Comiso created a time series of multi-year ice using 32 years of passive microwave data from NASA’s Nimbus-7 satellite and the U.S. Department of Defense’s Defense Meteorological Satellite Program, taken during the winter months from 1978 to 2011. This is the most robust and longest satellite dataset of Arctic sea ice extent data to date, Comiso said.

Younger ice, made from recently frozen ocean waters, is saltier than multi-year ice, which has had more time to drain its salts. The salt content in first- and second-year ice gives them different electrical properties than multi-year ice: In winter, when the surface of the sea ice is cold and dry, the microwave emissivity of multiyear ice is distinctly different from that of first- and second-year ice. Microwave radiometers on satellites pick up these differences in emissivity, which are observed as variations in brightness temperature for the different types of ice. The “brightness” data are used in an algorithm to discriminate multiyear ice from other types of ice.

Comiso compared the evolution of the extent and area of multi-year ice over time, and confirmed that its decline has accelerated during the last decade, in part because of the dramatic decreases of 2008 and 2012. He also detected a periodic nine-year cycle, where sea ice extent would first grow for a few years, and then shrink until the cycle started again. This cycle is reminiscent of one occurring on the opposite pole, known as the Antarctic Circumpolar Wave, which has been related to the El Niño-Southern Oscillation atmospheric pattern. If the nine-year Arctic cycle were to be confirmed, it might explain the slight recovery of the sea ice cover in the three years after it hit its historical minimum in 2008, Comiso said.

— A NASA News Release, Video here, Study abstract here

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20 Responses to The Arctic Death Spiral Continues: Thick, Multi-Year Sea Ice Melting Faster, NASA Study Finds

  1. John McCormick says:

    Northeast Pakistan suffered massive floods in 2010 and 2011, displacing more than 25 million people and destroying crops, land and livestock in the Swat Valley region.

    A more intense Asian Monsoon drifting to the West was the cause. The rains travelled farther north and to greter heights due to the heat of the Indian Ocean and Pakistan land beneath the clouds. As the rains fell in the snow-covered mountains to the North of the Valley, their effct was to melt massive amounts of snowpack that washed down streams and rivers in volumes never before seen.

    Is the Arctic death spiral the beginning of the Pakistan death spiral as well. These August floods may become permanent fixtures in Pakistan and Kasmir weather.

    There is much reseach still needed but the trend is evident. Asian monsoon are being affected bya the increasing heat in the Arctic.

  2. Tom King says:

    It seems to me that Antarctica and Greenland act as heat sinks. They convert Climate Change heat into melted ice. Once the north ice cap is eliminated I imagine a big single upward step in temperatures since one of the heat sinks will have been consumed. Greenland and Antarctica will obviously take a lot longer than the floating ice cap, but the same idea applies to them when they disappear.

  3. James says:

    Wow this is really happening. It seems so odd or just plain insane that we are not changing are lifestyles. Our children/grandchildren will be living with an ice-free Arctic. Wow…

  4. Yvan Dutil says:

    “He also detected a periodic nine-year cycle, where sea ice extent would first grow for a few years, and then shrink until the cycle started again. ”

    I think this means that MYI will get it again this year.

  5. Raymond X says:

    I’ve been concerned that the disappearance of the Arctic ice cap will alter seasonal weather patterns. The seasonal highs and lows will not form as they used to. They’ll be time-shifted, or a different size or strength, or in a different location, or all of these. The result, from the point of view of established agriculture: it precipitates where it shouldn’t, in amounts it shouldn’t, in forms it shouldn’t, at times it shouldn’t, instead of the places, amounts, forms and times that humanity has come to depend on for its fruits, grains, and vegetables. I’ve pinged a few climate scientists about this, and they are worried. I wish they would be more vocal.

    It seems that long before a destructive sea level rise, agriculture could fail on a global scale once the ice cap is complete goes, which may be within a decade, watching the attached video. That will start a feedback loop of further melting, and more jet stream/seasonal high-low disturbances. It’s pretty bleak. I agree with the comment above–why is no one alarmed about this except the few of us?

  6. Jacob says:

    I think that, for most folks, ignorance is bliss.

  7. Jacob says:

    This ice loss is happening too slow (by human life-spans) for the masses to comprehend the danger we face. If they looked at the geologic time-span they might be alarmed. I stress “might” here, because it seems that–more often than not–even the facts aren’t enough to persuade people.

  8. John Tucker says:

    Thats an outstanding visualization.

  9. Raymond X says:

    We’re not talking about human life spans anymore. If you’re not collecting Social Security, you could well see an ice-free Arctic one summer, and the extensive, structural, agriculture-destroying changes in the weather that will drive. It’s the imminence of this event, as suggested by the video, that is deeply disturbing.

  10. Leif says:

    If anyone can find one bit of good news in this report, I sure hope they tell me. Other than the fact that this report is on the web and not in a round file of a GOBP Desk some place, that is.

    Great observations in the comment thread as well. A couple if observations if I may.

    If the oldest is the saltest it stands to reason it has a lower melting point and will sublimate or melt first all else being equal.

    For each gram of water produced from ice requires ice 180 calories of heat absorption to just make the transition from 0C ice to 0Cwater. The same 180 calories will heat twice the amount of water to the almost boiling point of 90C. (Scary just writing that out. Please check this old shipwrights numbers.) Of course that is why your cooler will stay cold as long as there is some ice but warms quickly the moment it is all gone.

    q.e.d. Expect a distinct jump as the ice disappears.

  11. Rabid Doomsayer says:

    Ice is going, tornados in the Midwest and floods in Eastern Australia; didn’t we do this last year?

  12. Peter says:

    What will we see in a few years when the ice declines 60, 70, 80 percent from the 1979-2000 median for late summer. Will be be ‘Storms of My Grandchildren’ in its early stages?

  13. Peter says:

    An ice free arctic by 2020 in late summer- or now perhaps earlier far shorter then a lifetime.

  14. K.Odam says:

    Not quite.
    The older multi-year ice is less salty, and so newly-formed ice has a lower melting point.
    It’s 80 calories to melt one gram of ice, (and then another 80 calories to heat that gram to 80C).

  15. Leif says:

    Thank you K.O. For some reason I had 180 calories/g in my head. It was a long time ago and did not think of google at the time. Also I can see the reason of less salt in older ice because fresh would continually be piling on the top. There I was thinking of permeability of salt from the bottom. Live and learn. Why then for the faster melting? Perhaps it is the albedo effect of cumulative soot on the surface from years of sublimation of the surface? First and second year ice would have time to collect much less soot.

  16. From Peru says:

    If that first-year ice that now covers most of the Arctic (and is very near the North Pole itself)will face a “perfect storm” spring/summer like in 2007 that will be a major ice massacre…

    Imagine if on September 2012 only the multiyear ice survives, and we have a picture like that above but not showing just perennial ice extent, but total ice extent…


    At least that will shut up the crowd that mocked the NSIDC people that predicted an ice free Arctic in 2013…(but I suspect that Serreze, Maslanik,and the other people that launched the warning would like to be wrong about this!)

  17. John Tucker says:

    Loss of Arctic sea ice may lead to mercury deposits: NASA study

    The study found that thick, perennial Arctic sea ice was being replaced by a thinner and saltier ice that releases bromine into the air when it interacts with sunlight and cold, said Son Nghiem, a NASA researcher at the Jet Propulsion Laboratory in Pasadena.

    That in turn triggers a chemical reaction called a “bromine explosion” that turns gaseous mercury in the atmosphere into a toxic pollutant that falls on snow, ( )

    Nasa announcement ( )

  18. colinc says:

    “Why then for the faster melting? Perhaps it is the albedo effect of cumulative soot…”

    Perhaps, but be mindful that MYI presents a much greater surface-area to the rapidly warming sea. It seems too many still fail to grasp that most of the Arctic and Antarctic ice-melt is being perpetrated from below. Also recall that a corollary in thermodynamics states that the greater the delta-T between a hot source and a cold sink, the greater the rate of thermal energy transfer. Hence, thicker ice melts faster than thinner ice and the process is accelerating!

  19. Solar Jim says:

    Notice that in the early 1980’s multi-year sea ice covered much of the Eastern Siberia Continental Shelf. This is an area very rich in shallow sea methane hydrates, where kilometer wide plumes of methane have recently been observed outgassing.

    The albedo flip seems to be progressing rapidly (as one would expect). It seems our “geophysical experiment” (oxidizing lithosphere carbon) is leading to dramatic results. Too bad this is not a laboratory experiment. Gaia seems to have been stable, until contaminated (via corrupt human economics).

    This research is one component answer to the question “What could a trillion tons of human made carbonic acid gas do to the ecosphere?”

  20. ozajh says:

    I was at a bridge tournament in Eastern Australia for the last couple of days, and my travel was impacted by the rain. During that period 4 or 5 separate people (casual meets, like taxi drivers and counter staff) cracked jokes about Global Warming being BS. I understand similar things happened when the Eastern US got very high snowfalls a couple of years back.

    What concerns me is the prediction that AGW will lead to fewer, but more intense, rain events in an overall drying trend. And, to turn a biblical phrase, we’ve just had the 2 good years.

    To put it bluntly, if the flood-causing rainfall in Eastern Australia becomes a REGULAR occurence because of AGW the folks here will be saying ‘bring it on!’. The NET benefit will be truly massive.