Arctic Sea Ice Hockey Stick: Melt Unprecedented in Last 1,450 Years

JR: The Arctic sea ice Hockey Stick is more of a cliff…..

by Rob Painting, in a Skeptical Science cross-post

Many climate change “skeptics” obsess over the ‘hockey stick‘, and their discussion inevitably leads back to 1998, when climate scientist Michael Mann first published his paper indicating that current global warming was anomalous in the last 1000 years or so. In plain language, Mann’s work suggested that current warming was likely due to mankind’s carbon dioxide pollution, not any as-yet-unidentified, or yet-to-be-discovered or observed natural phenomenon.

Despite the “skeptics” cherry-picked focus on a  peer-reviewed paper more than a decade old, the science has moved on considerably since then. Paper after paper has basically affirmed that current warming is outside the bounds of natural variation, and therefore likely due to human activities. For example we have seen a sea level hockey stick, an underwater hockey stick, a South American hockey stick, an Arctic summer temperature hockey stick, a tropical glacier hockey stick, a North American mountain snowpack hockey stick, a glacier length hockey stick, and warming of Atlantic water into the Arctic hockey stick.

Into this league of hockey sticks, we have a just published scientific paper, (Kinnard [2011]), which shows that the Arctic sea ice retreat is also a hockey stick, and that the present rate of melt in the Arctic summer is unprecedented in the last 1,450 years. See figure 1. (Note that the hockey stick blade is facing down in this reconstruction).


Building a hockey stick

Because Arctic sea ice is influenced by both air and water temperatures, the study authors use a combination of Arctic ice core, tree-ring and lake sediments to reconstruct Arctic conditions over the last 2,000 years. As is often the case with these proxy reconstructions, the authors found the error bars in the reconstruction (the uncertainty) increased further back in time, due to a decreasing number of proxy records, and was not useful past 1,450 years ago.

When compared (validated) against historical sea ice observations it was found that the reconstruction not only had a dominant temperature-related signal, but that the proxy-based reconstruction also had a second signal which corresponded with variations in sea ice cover (extent), therefore confirming the 2nd network signal was a proxy for Arctic sea ice cover (as shown in figure 1).

Clearly there are periods in the reconstruction where rapid rates of ice loss occurred, but what stands out is that the length and rate of present day melt is unprecedented in the entire 1,450 year-long reconstruction. This is consistent with the Arctic summer temperature hockey stick (Kaufman [2009]) and warming of Atlantic water into the Arctic hockey stick (Spielhagen [2011]).

Arctic summer sea ice: going, going…………

2011 saw the 2nd lowest summer sea ice extent on record (after 2007), and even more dramatically,  this year saw the lowest ever recorded volume of Arctic summer sea ice.

This latest ‘hockey stick’ not only reinforces that current conditions in the Arctic are much warmer than the so-called Medieval Warm Period, but that sea ice is currently disappearing at a sustained speed that is unmatched in the last 1,450 years.

Rob Painting, Skeptical Science.

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30 Responses to Arctic Sea Ice Hockey Stick: Melt Unprecedented in Last 1,450 Years

  1. Colorado Bob says:

    From the AP story on the Permafrost study out today. …..
    The World Meteorological Organization this week said the worst of the warming in 2011 was in the northern areas — where there is permafrost — and especially Russia. Since 1970, the Arctic has warmed at a rate twice as fast as the rest of the globe.

    The thawing permafrost also causes trees to lean — scientists call them “drunken trees” — and roads to buckle. Study co-author F. Stuart Chapin III said when he first moved to Fairbanks the road from his house to the University of Alaska had to be resurfaced once a decade.

    “Now it gets resurfaced every year due to thawing permafrost,” Chapin said.

  2. otter17 says:

    Deniers: Recovery any year now!

  3. Colorado Bob says:

    Usually the first few to several inches of permafrost thaw in the summer, but scientists are now looking at up to 10 feet of soft unfrozen ground because of warmer temperatures, he said. The gases come from decaying plants that have been stuck below frozen ground for millennia.

  4. Colorado Bob says:

    NewsVine –
    In a recent video, University of Alaska Fairbanks professor Katey Walter Anthony, a study co-author, is shown setting leaking methane gas on fire with flames shooting far above her head.

    “Places like that are all around,” Anthony said in a phone interview. “We’re tapping into old carbon that has been locked up in the ground for 30,000 to 40,000 years.”

  5. Colorado Bob says:

    A commenter at NewsVine last week pointed out the energy transfer when water goes through it’s phase changes.
    Paraphrasing –
    It takes 80 times more energy the melt ice to water, than it does to heat the same amount of water 1C.

    We get that ice melted, and the heat really kicks in.

  6. WyrdWays says:

    Less a hockey-stick and more a scythe…

    Worryingly, that graphic only tracks an index that represents sea-ice area. The summer sea-ice volume is on an even faster crash, as the ice thins. Check-out the PIOMAS data from the excellent Arctic Sea-ice blog:

  7. Colorado Bob says:

    Now, 41 permafrost specialists have taken a new stab at adding up the potential of this pending Arctic belch, and it’s much worse than anyone thought.

    The thawing of permafrost over the century will dump up to five times more carbon into the air than some previous estimates — warming the Arctic by at least 3.5 degrees Fahrenheit by 2100, according to a survey of international scientists working together as the Permafrost Carbon Network.

    Under the worst-case scenario, the scientists predicted that the Arctic region could heat up even faster, with increases in the average annual temperature of 4.5 degrees by 2040 and 13.5 degrees by 2100.

    “Carbon will be released more quickly than models suggest, and at levels that are cause for serious concern,” wrote Edward Schuur from the University of Florida at Gainseville and Benjamin Abbott of the Institute of Arctic Biology at the University of Alaska Fairbanks, in a commentary published this week in the journal Nature.

  8. Lou Grinzo says:

    Yep, that 80 calories per cm^3 for the phase change is “interesting”, to say the least. It’s another good new/bad news situation, much like the ocean absorbing heat and CO2 — in the short run it reduces the impact but we pay for it later.

  9. Lore says:

    The obsession with Mann and hockey stick graphs is a diversionary rallying point for deniers. Like dog whistle calls to Gore and Hansen.

    Look at Watts right now, he’s peddling just as hard as he can to spin and prolong the fictional Climategate 2.0 ruse as a way to take the heat off of him from being continually beaten like a rented mule over Muller’s recent study and confirmation of warming. Last check, he was up to 50 updates to a sticky post at the top of his site referencing the hacked correspondence. He’s tied every delusional criticism from over the past 20 years to the emails. Surely, strictly for humanitarian reasons, someone needs to check his meds?

  10. prokaryotes says:

    Mandatory actions are required.

    Put Koch’s and all the rest of the loons on trial for high crimes/ ecocide / genocide.

  11. David B. Benson says:

    Well done.

  12. Paul Revere says:

    The medieval warm period was quite warm around the globe (Greenland and Vinland, indeed). Perhaps it is soot that is making the melting of Arctic ice so much worse.

  13. prokaryotes says:

    Look into the history of the earth and what happened each time when such “pronounced” observation can be made.

  14. Mulga Mumblebrain says:

    I just heard another news story that lets you know just what intellectual and moral depths our local politicians and businessmen infest. The Premier of Queensland was announcing, with her usual girlish enthusiasm, that a coal port on the Queensland coast is to have its export capacity increased by 2000%. She almost suffered a fit of delight when she boastfully announced the number. I believe she has children, whose future and that of their children is ‘2000%’ stuffed. What’s even better, these mega-ports massively pollute the nearby Great Barrier Reef, hastening its demise, and the chances of ships foundering on the reef will rise dramatically, too. Talk about a Death Wish, and so full of herself, too.

  15. Mulga Mumblebrain says:

    Well spotted wyrd. The climate destabilisation Nemesis, swinging his scythe back and forth, harvesting humanity.

  16. Mulga Mumblebrain says:

    It must, and I hope will, be done one day. The crimes of the denialist industry will cause death and suffering besides which the greatest previous crimes in humanity’s sad history simply pale into relative insignificance. It is a question of justice.

  17. Mulga Mumblebrain says:

    Does anyone know if these methane releases have explosive potential, and just how great could it be? I do know that melting submarine clathrates can cause undersea landslides and propagate mega-tsunamis, as hit east Scotland a few thousand of years ago. It all keeps getting cheerier and cheerier.

  18. Colorado Bob says:

    Lou –
    Thanks for the comment . Coupled with this ball of wax is another one of those iron clad laws from the age Newton.
    Gases are lousy heat batteries , unless they are compressed . But water is the standard , from which all other things are measured.
    It carries the #1 on the scale, few things measure higher than #1. Most of the world around us has a fraction of the heat that can be stored in water.

    A few weeks ago , I read that the ocean at depth, during the PETM was near 60F.

  19. Colorado Bob says:

    PR –
    That’s still a ” Man Made Deal “.
    Like dust landing on the snow pack in the San Juan Mountains of Southwest Colorado.

  20. Colorado Bob says:

    PR –
    Try this thought experiment :
    “Black ice” causes car wrecks, therefore all car wrecks are caused by “black ice”.

    Whatever drove the medieval warm period, is not related to the Trillion tons of carbon man has dug-up and dumped back into the system in the last 170 years.

  21. Colorado Bob says:

    PR –
    Try this thought experiment :
    CO2 is a “trace gas” by weight and volume.
    The Ebloa virus by weight and volume in the human body is even smaller, it caries a 64% death rate.

    Nature is packed with things that don’t need much change to make a big difference.

  22. Colorado Bob says:

    Joe –
    When you guys comment on this Permafrost report use this picture :

    This handout photo, taken in 2009, provided by University of Alaska, Fairbanks, shows research assistant professor Katey Walter Anthony igniting trapped methane from under the ice in a pond on the Fairbanks campus. Massive amounts of greenhouse gases trapped below thawing permafrost will likely vent into the air over the next several decades, accelerating and amplifying global warming, scientists warn. (AP Photo/Todd Paris, University of Alaska, Fairbanks)

  23. Mulga, the question “Don’t these people have kids?” is the one that constantly refrains in my noggin. I can understand greed and avarice and sloth…but it really boggles my mind that people with kids can hang them out to dry like they are doing. Rampant. Puzzling. Deep psychological weirdness at play.

  24. Looking at that ice cliff graph all I can think of is a StrangeLove-ian vision of Our Dear Prime Minister Harper riding a tar sands barrel over the edge of it, freefalling down to China yelling “Wooohooo!”

  25. Spike says:

    “And the picture is even more alarming for the end of the century. The scientists calculate that about than 300 billion metric tons of carbon will belch from the thawing Earth from now until 2100.”

    That alone takes us very close to the trillionth tonne with no further man made emissions. Climate change is about to take the baton from us and run.

  26. perceptiventity says:

    And Venus Syndrome is not that farfetched an idea afterwards, is it ? Is there more research on this hypothesis?

  27. Raul M. says:

    That the dust storms will provide some way for some of the co2 to change back to the ground?Can’t do much biochar out of windy and dust. The areas that would provide material for biochar have living plants that provide what’s that old way of saying fodder for the fire, windfall for the stove, fertilizer for the crop, root base for the hydroponics, etc…

  28. dick smith says:

    I would like a straight answer from NASA’s James Hansen. What level of atmospheric carbon (or other GHG)would be necessary to initiate an irreversible runaway Venus Syndrome? And, are there enough conventional and unconventional sources of carbon left on the planet to do that or not? In short, is it theoretically possible? And, if so, at what point does it become more likely than not (more than 50%)?

  29. Mulga Mumblebrain says:

    It’s a variation on the denial of death. Once religious belief in a grand eternal transcendental hotel in the sky died away, we were left to face annihilation alone. Very many people simply deny it, put it out of mind and go on as normal, as if it will disappear like a bad dream. Climate destabilisation is death, death for billions, death for our civilization, possibly death for the species. And a second, and final death, for our ancestors, who lived on in us and future generations, and for the great exceptions to the rule of human mediocrity, in science, the arts, philosophy and our nobler achievements. I can see why people prefer to pretend it ain’t happening. Of course, most politicians, businessmen and media propagandists have the moral and intellectual endowments of a protozoan stripped of its flagella, therefore are probably convinced denialists.

  30. Bob Doublin says:

    Have you even read his book Storms of My Grandchildren? He quite clearly states that if we burn the Canadian Tar Sands, he considers it more than likely that a Venus Effect will take place on Earth.