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Author Topic: Iceland Holocene Temperature reconstruction  (Read 3883 times)

Martin Gisser

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Iceland Holocene Temperature reconstruction
« on: May 06, 2017, 03:33:50 PM »
A lukewarmist friend of mine keeps talking about temperatures in Iceland having been significantly warmer than today at some time during the Holocene. The only reference I found is this paywalled thesis:

Black, Jessica L.: Holocene climate change in south-central Iceland: A multi-proxy lacustrine record from glacial lake Hvítárvatn (2008)
From the abstract:
Quote
There are two phases of early to middle Holocene warmth in south-central Iceland in the last 10.2 ka, from <10.2–8.7 ka ago and coincident with peak summer solar insolation at that latitude at 11 ka ago, and peak warmth from 7.35–5.5 ka ago which lags peak insolation by several millennia. Langjökull, Iceland's second largest ice cap, largely disappeared during these two phases indicating temperatures were warmer than today.
http://gradworks.umi.com/33/15/3315776.html
The rest is paywalled. I couldn't find anything quotable elsewhere.

Do you have any other accessible source? Or maybe send me a complete PDF?

Martin Gisser

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Re: Iceland Holocene Temperature reconstruction
« Reply #1 on: May 06, 2017, 04:24:05 PM »
P.S.: The vanishing of the Langjökull would be consistent with Holocene climatic optimum arctic temperatures of 2-3°C above today. But he keeps insisting about 5°C. I trust his photographic memory. Where did he get this from?

jai mitchell

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Re: Iceland Holocene Temperature reconstruction
« Reply #2 on: May 06, 2017, 06:03:33 PM »
 ::)

This paper from lakebed samples shows that iceland was at most 2-3C warmer than the 1961-1990 values (and most likely around 1.5C) https://www.researchgate.net/profile/Peter_Langdon3/publication/223633044_Early_Holocene_climate_variability_and_the_timing_and_extent_of_the_Holocene_Thermal_Maximum_HTM_in_Northern_Iceland/links/02e7e531fe097c774d000000/Early-Holocene-climate-variability-and-the-timing-and-extent-of-the-Holocene-Thermal-Maximum-HTM-in-Northern-Iceland.pdf

however, it is also known that variations in the AMOC (gulf stream) current in the north atlantic produces large temperature swings.  It is these swings that have caused large variability in the Greenland ice core sample (and european temperature record).  Lukewarmist will often attach themselves to the intentional lies of paid deniers who present these regional variations as global proxies which they are obviously not. 

http://www.nature.com/nature/journal/v457/n7230/full/nature07717.html

Finally, the real issue is that this person you are talking about has a fundamental misconception of what effect the Milankovich cycles have on northern hemisphere temperatures.  That these cycles operate on scales that are thousands of years long and that at current solar forcing values, if it wasn't for early human CO2 and CH4 emissions, we would have plunged into a full ice age about 3,000 BC. 

instead we are set to jump above any previous warm period in the 800,000 year ice core record.

for more see:  http://environmentalscience.oxfordre.com/view/10.1093/acrefore/9780199389414.001.0001/acrefore-9780199389414-e-192

This is an excellent short video of Ruddiman explaining his work: 

Also the forum thread here:  http://forum.arctic-sea-ice.net/index.php/topic,852.0.html
« Last Edit: May 06, 2017, 06:11:20 PM by jai mitchell »
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Laurent

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Re: Iceland Holocene Temperature reconstruction
« Reply #3 on: May 07, 2017, 04:47:13 PM »
It looks like I can read the paper... It may be because I have installed a firefox plugin that is called "unpaywall", it does look for free copy available elsewhere among a list of available sources. http://unpaywall.org/

Martin Gisser

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Re: Iceland Holocene Temperature reconstruction
« Reply #4 on: May 07, 2017, 05:17:21 PM »
It looks like I can read the paper... It may be because I have installed a firefox plugin that is called "unpaywall", it does look for free copy available elsewhere among a list of available sources. http://unpaywall.org/
Alas it is not working on my Android tablet, neither Chrome nor Firefox. (This is the last drop in my bucket. Will get rid of this f'en piece of ridicu-lousy junk...)

Martin Gisser

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Re: Iceland Holocene Temperature reconstruction
« Reply #5 on: May 07, 2017, 05:37:03 PM »
::)

This paper from lakebed samples shows that iceland was at most 2-3C warmer than the 1961-1990 values (and most likely around 1.5C) https://www.researchgate.net/profile/Peter_Langdon3/publication/223633044_Early_Holocene_climate_variability_and_the_timing_and_extent_of_the_Holocene_Thermal_Maximum_HTM_in_Northern_Iceland/links/02e7e531fe097c774d000000/Early-Holocene-climate-variability-and-the-timing-and-extent-of-the-Holocene-Thermal-Maximum-HTM-in-Northern-Iceland.pdf

however, it is also known that variations in the AMOC (gulf stream) current in the north atlantic produces large temperature swings.  It is these swings that have caused large variability in the Greenland ice core sample (and european temperature record).  Lukewarmist will often attach themselves to the intentional lies of paid deniers who present these regional variations as global proxies which they are obviously not. 

http://www.nature.com/nature/journal/v457/n7230/full/nature07717.html

Finally, the real issue is that this person you are talking about has a fundamental misconception of what effect the Milankovich cycles have on northern hemisphere temperatures.
Thanks for the links! I tried to explain him the local character of ice core temp reconstructions, AMOC fluctuations, Lake Agassiz floods, Milankovich, etc. and fossil fools propaganda. He remains a lukewarmist. So I hoped for some evidence that he got this Iceland thing from liars.
(He's no stupid and very seriously looking for truth. Alas his Russian is better than his English. And he is a bit crazy, if not paranoid. Mental wounds from having been in the dungeons of communist east Germany.)