New Arctic Study Finds Spring Sea Ice Melted 2 Months Earlier Than Today During Roman, Medieval Times

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Scientists have determined that today’s Arctic sea ice concentrations are still much higher than they have been for most of the last several thousand years, undermining claims that modern era Arctic sea ice changes are remarkable, unusual, or unprecedented. 

Source: Kolling et al., 2018

In the graphical illustration of Late Holocene West Greenland sea ice changes shown above, Kolling and colleagues (2018) indicate that both present-day and Little Ice Age era (~1300s to 1800s AD) sea ice does not melt until May.(Fig. 6a).

During most of the last 2,200 years — especially during the Medieval Warm Period (MWP) and Roman Warm Period (RWP) — spring sea ice melted in March, two months earlier than today (Fig. 6b).

The authors attribute the lower-than-today sea ice concentrations and warmer temperatures during the MWP and RWP to a “self-amplifiying system” involving variations in solar activity and the AMO.  Atmospheric CO2 concentrations are not mentioned in the paper as a factor influencing sea ice changes.

The period between 2.2 and 1.2 kyr BP, with lower than modern sea ice conditions in Disko Bugt (Fig. 6b), coincides with generally warm conditions over the Greenland Ice Sheet.”
“A self-amplifying system may have caused the environmental changes observed in Disko Bugt area as follows: solar triggered Arctic sea ice melt [Ruzmaikin et al., 2004] increases freshwater supply towards the North Atlantic causing a reduction in sub-polar gyre activity and AMO [Holland et al., 2001, Schmith et al., 2003] as described by Sha et al. [2016].”

Consistent with other reconstructions for the region (Kryk et al., 2017Durantou et al., 2012Yamamoto et al., 2017Perner et al., 2018), proxy evidence shows that current sea ice conditions are only modestly different than the indicated conditions during the past few centuries.

Source: Kryk et al., 2017Durantou et al., 2012Yamamoto et al., 2017Perner et al., 2018

The lack of any unusual or remarkable change in sea ice conditions during the modern era relative to the past suggests there is a lack of conspicuous connection between rising anthropogenic CO2 emissions and the Arctic climate.


Kolling et al., 2018

New insights into sea ice changes over the
past 2.2 kyr in Disko Bugt, West Greenland

“Our biomarker record indicates that Disko Bugt [West Greenland] experienced a gradual expansion of seasonal sea ice during the last 2.2 kyr. Maximum sea ice extent was reached during the Little Ice Age around 0.2 kyr BP. Superimposed on this longer term trend, we find short-term oscillations in open water primary production and terrigenous input, which may be related to the Atlantic Multidecadal Oscillation and solar activity changes as potential climatic trigger mechanisms.
The period between 2.2 and 1.2 kyr BP, with lower than modern sea ice conditions in Disko Bugt (Fig. 6b), coincides with generally warm conditions over the Greenland Ice Sheet.”
“Overall, IP25 concentrations remained relatively low and constant until 1.2 kyr BP, followed by a gradual increase (Fig. 3e). The lowest [sea ice] concentrations, around 0.06 µg/gTOC, are observed in the lowermost core section from 2.2 to 1.5 kyr BP (Fig. 3e).”
During the last 0.1 kyr, all biomarker concentrations showed an increase, brassicasterol and HBI III reach maximum values in the uppermost sample (80 µg/gTOC and 1.8 µg/gTOC, respectively; Fig. 3b, d).”

Source: Kolling et al., 2018
[During the Little Ice Age (0.7–0.2 kyr BP)] our biomarker record supports harsher sea ice conditions, possibly similar to conditions as observed today (Fig. 6b), indicated by strong increased in IP25 concentration and the PDIP25 index (Fig. 4c, d).”

Source: Kolling et al., 2018
AMO variability has been linked to solar activity changes [Knudsen et al., 2011]. Changes in incoming radiation may influence sea ice extent and the Greenland Ice Sheet behaviour [Ruzmaikin et al., 2004] and consequently affect the freshwater discharge/inflow [Schmith et al., 2003] and nutrient availability to the area. A self-amplifying system may have caused the environmental changes observed in Disko Bugt area as follows: solar triggered Arctic sea ice melt [Ruzmaikin et al., 2004] increases freshwater supply towards the North Atlantic causing a reduction in sub-polar gyre activity and AMO [Holland et al., 2001, Schmith et al., 2003] as described by Sha et al. [2016]. This may in turn cause distinct changes in WGC composition and meltwater supply from the Greenland Ice Sheet that affects phytoplankton blooms in West Greenland.”
“We find that the Disko Bugt area was influenced by seasonal sea ice over the last 2.2 kyr BP. The overall sea ice trend indicates a development from a reduced sea ice cover during early spring, with sea ice algae productivity hampered by light availability to a gradual extend of the sea ice season from 1.2 kyr BP onwards. This change in sea ice extend is parallel to decreasing Northern Hemisphere atmospheric temperatures and culminates in the Little Ice Age around 0.2 kyr. We assume that modern conditions, with sea ice present until late spring and the presence of a stable ice edge at Disko Bugt, established around that time [~200 years ago].”
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22 responses to “New Arctic Study Finds Spring Sea Ice Melted 2 Months Earlier Than Today During Roman, Medieval Times”

  1. Lasse

    Greenland has name from that time!
    Dwellings is abandoned since then.
    Corps did not develop during a short summer.

  2. Bitter&twisted

    More “settled science”.

  3. spike55

    Again, all the data and science shows that the world is really only a small bump out of the COLDEST period in 10,000 years.

    We should be very thankful for that slight NATURAL warming as it has been highly beneficial, along with raised CO2 levels, to all life on this carbon based planet of ours.

  4. Steve

    Those scientists from several thousand years ago must have been extremely concerned about AGW melting the ice.

  5. spike55

    Geologists and realist in the climate area have know for ages that most of the Interglacial has been significant;ly warmer than now.

    There is even a period named for the cooling that started some 3000 years ago

    Its called the NEOGLACIATION, and its the period when many of the current world glaciers and large ice caps started to form and stay formed over the whole year, reaching their peak levels during eth anomalous cold period of the Little Ice Age.

    The world has recovered slightly from that COLDEST of period, exposing 2000-3000 year old tree stumps under retreating glaciers, allowing the investigation of Greenland through melting permafrost exposing Viking burials and artefacts from the MWP.

    Still some warming need to get fully back to the MWP,

    … and lot more to get back to the Holocene Optimum.

  6. SebastianH

    The lack of any unusual or remarkable change in sea ice conditions during the modern era relative to the past suggests there is a lack of conspicuous connection between rising anthropogenic CO2 emissions and the Arctic climate.

    Yeah, the decreases in ice mass, volume and extent are surely totally normal and unremarkable. Nothing to see here, since it has happened before only it wasn’t CO2 back then.

    Oh dear …

    1. spike55

      Yes, we can all agree that current levels of sea ice are actually rather HIGH compared to the last 10,000 years.

      Not surprising seeing the world temperature is barely a bump above the coldest period in 10,000 years.

    2. spike55

      “only it wasn’t CO2 back then.”

      ABSOLUTELY ZERO EVIDENCE that CO2 has anything to do with the slight warming, seb

      Do you have any evidence????

      THEN PRODUCE IT !!!

      TOTALLY EMPTY so far.

      We have been waiting a long, long, long, long time for this !!

      You have FAILED to deliver..

      You are a sad, pathetic embarrassment to the AGW cult.

      Unable to support even their most basic conjecture.

    3. Bitter&twisted

      Oh dear indeed.
      My two children have a name for people who are a bit slow.
      “Special”.
      From now on you are my extra special troll.

      1. Yonason

        I think his most “special” troll power lies in his exceptional SJW/Feminist math ability. (must have been an “A+” student in THAT)
        https://uncommondescent.com/intelligent-design/progressive-war-on-science-takes-dead-aim-at-math/

        (…that and his skill at deploying logical fallacies and evasion, all of which he is able to hone to perfection thanks to being allowed to continue to post here.)

        Other speshul powerz…

        bogus citations
        evasion
        deception
        selective memory

        …and so MANY more. In short, if it’s on this list, SebH has probably invoked it.
        http://www.nizkor.org/features/fallacies/

        =============================

        NOTE – With math skills like those being taught in some schools today, Leftists appear to be trying to raise an army of critical-thinking-deficit zombies, loyal only to false post-modern narratives. It’s no wonder Western Culture appears under attack. It is. John Ray has an excellent expose on it, here.
        http://jonjayray.tripod.com/pomo.html

  7. Yonason

    But, but, but, …it’s NEVER been warmer before…
    https://www.youtube.com/watch?v=PxKek_MO_8w&app=desktop

    …except when it has, for most of the past.

    Many points made there, including also one about error bars which is the same point made by Lindzen, i.e., that anomalies are insignificant when you consider the relatively massive errors in the data used to generate them.

    So, basically, there isn’t any conclusive data that the world has warmed appreciably, let alone that CO2 is “causing” it to do so.

    1. SebastianH

      Lindzen and a video of an obscure Professor Bob Carter … you surely have found out how to convince people of your weird opinion about reality with trustworthy sources 😉

      1. spike55

        Those two were probably the most trustworthy REAL scientists in the climate science area.

        First, they were actual scientists.

        Second, they never allowed brain-washed mantra to rule their thinking.

        Third, they do not have any agenda apart from the facts

        Fourth, the very fact that seb thinks they are not, PROVES that they are.

        Seb is renowned LIAR and COWARD, and basically everything he says should be taken as being a load of brain-hosed, anti-science garbage, diametrically opposed to reality.

    2. Yonason

      BIO OF AN “OBSCURE” PROFESSOR

      “Bob Carter was a palaeontologist, stratigrapher, marine geologist and environmental scientist with almost 50 years of professional experience. He earned degrees from the University of Otago (New Zealand) and the University of Cambridge (England). He held tenured academic staff positions at the University of Otago (Dunedin) and James Cook University (Townsville), where he was Professor and Head of the Department of Geology and its successor, the School of Earth Sciences, between 1981 and 1997.”
      https://www.jcu.edu.au/news/releases/2016/january/death-of-prof-bob-carter

      Pierre, please do something about the lying ad hom spewing sack of troll spit self-identifying itself as SebastianH.

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