Tree Remains Found Buried Beneath Today’s Glaciers Date To The Warmer-Than-Today Medieval Warm Period

A new study (Kullman, 2021) suggests ~9000-year-old tree remains can be found buried in “currently empty snow hollows and glacier cirques” at elevations 600-700 m higher than where trees can grow today, implying a >3°C warmer Early Holocene climate. Treelines were still 75-100 m higher during the Medieval Warm Period…and even during the 15th and 17th centuries.

Claims that current climate warmth and glacier recession are both unusual and unprecedented for recent millennia are wholly contradicted by a wide array of megafossil tree evidence in the Scandes (northern Sweden). Pine and birch remains now emerging from regions thought to be “permanently” too cold for trees to survive can be carbon-dated to 1200 A.D., which was within the latter stages of the Medieval Warm Period.

“In this context the conspicuous and poorly understood subalpine heaths in the Abisko Valley (Josefsson, 1990) deserve attention. These are ‘permanently’ treeless areas in the lower subalpine birch belt. Current frost-heave in non-sorted circles have exposed pine megafossils, dating to the Medieval Warm Period around AD 1200 (Fig. 12). Apparently, they died during the subsequent Little Ice Age [10].”

Tree trunk remains located 600 to 700 meters atop the warmth-demanding temperature thresholds of modern treelines in northern Sweden date to the Early Holocene. Pine wood dated to the 13th, 15th, and 17th centuries have also been found at elevations 75 to 100 meters higher than today.

Using the lapse rate formula (i.e., temperature drops -0.6°C for every 100 m in altitude), this megafossil evidence affirms temperatures were at least 3°C  warmer than today from about 9,500 to 8,500 years ago, and perhaps 0.5°C warmer during Medieval times.

Image Source: Kullman, 2021

Treeline evidence also suggests temperatures  in the European Alps were “3.1°C higher than today” until about 4,000 years ago, when the climate began “deteriorating” (Badino et al., 2018). The reconstruction indicates modern temperatures are among the coldest of last 9,000 years.

Image Source: Badino et al., 2018

11 responses to “Tree Remains Found Buried Beneath Today’s Glaciers Date To The Warmer-Than-Today Medieval Warm Period”

  1. Ziane
  2. Lasse

    In Norway You have a glacier named Nigardsbreen.

    “The name Nigard is derived from the farm by the same name. In 1748 the farm was shattered off the glacier when it grew approximately three kilometres from 1700 – 1748.”

  3. Nalezené zbytky stromů pohřbené pod současnými ledovci se datují do Středověké teplé periody a do časů ještě teplejších -
  4. Chris Hanley

    As discussed above this is one of a number of studies that show previous Holocene temperatures considerably higher than the IPCC’s +1.5C ‘safe limit’ above pre-industrial LIA temperatures; an average of 3C above the current temperature over an extended period would suggest even higher (and lower) temperatures over shorter time periods.
    Commenting as a layman altitudinal and latitudinal tree-line studies are far more convincing evidence of past climate than proxy studies because they rely on actual material evidence that can be radiocarbon dated.
    That previous Holocene temperatures were much higher than today makes attribution arguments i.e. to what extent the purported temperature rise since 1950 (~0.6C HADSST3) was due to human CO2 emissions, marginal.

  5. Roger

    Some part of the high altitude of the fossil wood can be ascribed to isostatic rebound after the retreat of the ice sheet as climate entered our present interstadial. However, it would still imply a significantly warmer climate around the Holocene Thermal Maximum.

    1. Martin Reed

      The Kullman paper already allows for isostatic uplift (100m).So no error there.

  6. Jdeschen

    The same sort of evidence exists in the Canadian Rockies, for example at the Peyto Glacier. Used to be a Parks Canada sign pointing out the ancient (9000 years old) tree remains being exposed by the melting glacier. It was removed when it didn’t agree with Federal Government policy.

  7. tom0mason

    These forest remains will always be the problem for the irrational AGW advocates (aka Climate Catastrophe irrationals), as it show that in the past a warmer planet was never a problem and that CO2 could not the cause of it. Nature coped very well, no catastrophe ever happen during these warm periods, in fact life on the planet thrived.

  8. Gerald the Mole

    A UK politician once said “why look into the crystal [ball] when you can read the future in a book”.

  9. Weekly Climate and Energy News Roundup #454 – Climate-

    […] Tree Remains Found Buried Beneath Today’s Glaciers Date To The Warmer-Than-Today Medieval Warm Per… […]

  10. Sidian

    A quick question someone might be able to answer:

    Shouldn’t there also be a difference in treeline height due to increased CO2? I mean all research shows plants have a much easier time growing these days meaning trees should be climbing up hills and mountains. This would make the 500-600m difference even larger temperature-wise if you consider the fact, that CO2 made up for some of the temperature difference.

    Am I wrong?

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