Guest essay by David Archibald
Wiggle-matching has been used by the best. Hubert Lamb, considered to be the most meticulous climatologist of all time, used wiggle-matching in this wind data graph he published in 1988:
He had plotted up 600 years of wind data at London, noted a 200 year periodicity and copied the line 200 years to the right to make a forecast.
One of the puzzles of the last 300 years of climate is the temperature drop of 1740. It came out of the blue after a number of warm years in the 1730s. There is nothing in the Be10 record or the volcanic record to suggest a cause.
It came a couple of years after the peak of a fairly strong solar cycle. The event of 1740 attracted the attention of Briffa and Jones in their 2006 paper “Unusual Climate in Northwest Europe During the Period 1730 to 1745 Based on Instrumental and Documentary Data”. From the abstract of that paper,” This study focuses on one of the most interesting times of the early instrumental period in northwest Europe (from 1730–1745) attempting to place the extremely cold year of 1740 and the unusual warmth of the 1730s decade in a longer context.” The only conclusion that they came to was climate might vary more than is commonly accepted.
So what does that period up to 1740 wiggle-match with? It matches with the warmth of the last 30 years:
The graph above shows the Central England Temperature (CET) record from 1703 to 1745 as the blue line. Plotted on it is the CET record from 1978 to 2012. Normally when you align 34 year lengths of temperature records you don’t get any correlation. The correlation on this particular matchup is 0.112. The statisticians amongst us can argue over whether or not anything can be read into that. If something can be read into it, we only have to wait two years to experience the consequences. The spike down is also prominent in the de Bilt record:
herkimer says:
“..I cannot find any specific solar event connection to the 1740 cold event unless solar events cause extended negative AO type of conditions that lasted for about a year.”
This NAO reconstruction indicates the colder periods from Jan, May and Oct that I mentioned earlier. ftp://ftp.ncdc.noaa.gov/pub/data/paleo/historical/north_atlantic/nao_mon.txt
And again, there many very cold winters at solar cycle maximums because there’s often a drop in the Ap index there.
The utterly cold year of 1740 in Northern Europe was associated with the massive 1739 eruption of Mt. Hekla in Iceland, killing 10,000 islanders equivalent to 20% of Iceland’s entire population.
So, do book your 2015 summer holiday with confidence!
@ur momisugly Jens Kieffer-Olsen
Wikipedia lists no eruption in 1739:
http://en.wikipedia.org/wiki/Hekla
Nor at Oregon state archive
http://volcano.oregonstate.edu/vwdocs/volc_images/europe_west_asia/eruption_history.html
I think you are confused.
Check out this link: http://runeberg.org/univers/0476.html
(Sorry it’s in Swedish.) It describes the 4 months long eruption of Mt. Hekla in 1739.
DMarshall says: Does that have anything to do with the extremely warm temps in Alaska right now or is that a separate phenomenon. I’ve heard reports of temps ranging from 82 – 98 degrees across the state after having unusually cold temps until just recently.
I am in Alaska right now and actually, the weather is pretty normal–the last few months were colder than usual and June has been just a little above average–very little: http://tinyurl.com/k7uelco
I was here in the late eighties and early nineties and it was remarkably good weather then, I could not believe how sunny and beautiful the summer days were. for YEARS,
The last few years have been rainy and cold and dreary. Horrible weather that the local news doesn’t really report because we rely on tourism. But the nice weather is just that, nice weather and nothing unusual. In other words, the few hot days we have had is not “extremely warm.” It is the weather we had in the late eighties and early nineties.
PS-I’m a Marshall too.
Fascinating. Major eruptions of a major volcano only attested in one old (1914) Swedish text.
Here’s part of the text in Swedish:
“av vars 23 verksamma vulkaner det 1500 m hoga Hekla ar den mest bekanta:
Ett av de valdsammaste utbrott man kanner pa Island intraffade 1739, da lavastrommarna fyllde
Skapt-ons och Herrfirflojts dalar till en maktighet av 125-190 m. och nadde den ena 84, en annan 34 kms langd samt under sina till 12-15 kubikkilometer uppskattade, stelnade massor begrovo 500 kvadratkilometer landyta.”
Here’s how Google translates it (not that well), with a couple of obvious adjustments:
“of the 23 active volcanoes, the 1,500 m high Mount Hekla is the most familiar:
One of the men feel parish pillars (?) outbreak in Iceland occurred in 1739, of lava streams filled
Skapt-ons and Herrfirflojts valleys to a thickness of 125-190 m, reaching one 84, another 34 kms length and during their 12-15 cubic kilometers appreciated, solidified masses buried 500 square kilometers.”
Some in the know think Hekla is about to blow now:
* http://volcanocafe.wordpress.com/2013/04/29/countdown-to-hekla/
Should Hekla erupt and cause a similar temperature drop as 1740, my jaw will be on the floor.
As it is indeed suspicious with only one source pointing to Mt. Hekla erupting in 1739, I asked a friend in Iceland for validation. He pointed me to the complete list ( in Icelandic ) of volcanic activity on the island: http://is.wikipedia.org/wiki/Eldgosaannáll_Íslands
This source mentions exactly the same locations Skaftá and Hverfisfljóti in the context of Laki erupting in 1783 as does Oscar Heinrich Dumrath in his description of an eruption of Hekla 1739. My conclusion is that Dumrath has gotten himself confused or was misinformed when he published his book in 1914. There was no eruption in 1739 in Iceland. – Project Runeberg makes available scholarly books from long ago, but doesn’t correct errors and typos on the fly 🙂
As I don’t subscribe to the idea of the temperature spike of 1740 being a ‘natural’ one, I wish to draw attention to the major eruption in 1739 of Mt. Shiveluch, also known as ‘The Bad Boy of Kamchatka’: http://www.paleoglaciology.org/regions/Kamchatka/ShiveluchVolcanoEruptions/
Alternatively the culprit could be Mt. Shikotsu ( Tarumai ), erupting from Aug.19 to Aug. 31, 1739: http://volcano.oregonstate.edu/shikotsu
Jens Kieffer-Olsen says:
June 25, 2013 at 10:45 am
————————————-
Would the climatic effects of those two NW Ring of Fire eruptions fall outside the background of ordinary annual volcanic activity?
That’s a good question. In my impression behind negative temperature spikes with a duration of one or a couple of years you eventually may identify an angry volcano. We know that Tambora caused the ‘Year without a summer’ in 1816, but which one caused the Great Frost of 1740 or any other Great Frost of long ago is not so obvious. It seems though that Mt. Shikotsu could be partly to blame. Quoting from page 52 of:
http://www.geos.ed.ac.uk/~studhope/Recent_Publications/D'Arrigo_et_al_2008_Nature_Geoscience.pdf
“[…] minor cooling follows the Shikotsu, Japan, eruption (1739, -0:33 C, VEI 5)”.