From Cardiff University
Sun’s energy influences 1,000 years of natural climate variability in North Atlantic
Changes in the sun’s energy output may have led to marked natural climate change in Europe over the last 1000 years, according to researchers at Cardiff University.
Scientists studied seafloor sediments to determine how the temperature of the North Atlantic and its localised atmospheric circulation had altered. Warm surface waters flowing across the North Atlantic, an extension of the Gulf Stream, and warm westerly winds are responsible for the relatively mild climate of Europe, especially in winter. Slight changes in the transport of heat associated with these systems can led to regional climate variability, and the study findings matched historic accounts of climate change, including the notoriously severe winters of the 16th and 18th centuries which pre-date global industrialisation.
The study found that changes in the Sun’s activity can have a considerable impact on the ocean-atmospheric dynamics in the North Atlantic, with potential effects on regional climate.
Predictions suggest a prolonged period of low sun activity over the next few decades, but any associated natural temperature changes will be much smaller than those created by human carbon dioxide emissions, say researchers.
The study, led by Cardiff University scientists, in collaboration with colleagues at the University of Bern, is published today in the journal Nature Geoscience.
Dr Paola Moffa-Sanchez, lead author from Cardiff University School of Earth and Ocean Sciences, explained: “We used seafloor sediments taken from south of Iceland to study changes in the warm surface ocean current. This was done by analysing the chemical composition of fossilised microorganisms that had once lived in the surface of the ocean. These measurements were then used to reconstruct the seawater temperature and the salinity of this key ocean current over the past 1000 years.”
The results of these analyses revealed large and abrupt temperature and salinity changes in the north-flowing warm current on time-scales of several decades to centuries. Cold ocean conditions were found to match periods of low solar energy output, corresponding to intervals of low sunspot activity observed on the surface of the sun. Using a physics-based climate model, the authors were able to test the response of the ocean to changes in the solar output and found similar results to the data.
“By using the climate model it was also possible to explore how the changes in solar output affected the surface circulation of the Atlantic Ocean,” said Prof Ian Hall, a co-author of the study. “The circulation of the surface of the Atlantic Ocean is typically tightly linked to changes in the wind patterns. Analysis of the atmosphere component in the climate model revealed that during periods of solar minima there was a high-pressure system located west of the British Isles. This feature is often referred to as atmospheric blocking, and it is called this because it blocks the warm westerly winds diverting them and allowing cold Arctic air to flow south bringing harsh winters to Europe, such as those recently experienced in 2010 and 2013.”
Meteorological studies have previously found similar effects of solar variability on the strength and duration of atmospheric winter blockings over the last 50 years, and although the exact nature of this relationship is not yet clear, it is thought to be due to complex processes happening in the upper layers of the atmosphere known as the stratosphere.
Dr Paola Moffa-Sanchez added: “In this study we show that this relationship is also at play on longer time-scales and the large ocean changes, recorded in the microfossils, may have helped sustain this atmospheric pattern. Indeed we propose that this combined ocean-atmospheric response to solar output minima may help explain the notoriously severe winters experienced across Europe between the 16th and 18th centuries, so vividly depicted in many paintings, including those of the famous London Frost Fairs on the River Thames, but also leading to extensive crop failures and famine as corroborated in the record of wheat prices during these periods.”
The study concludes that although the temperature changes expected from future solar activity are much smaller than the warming from human carbon dioxide emissions, regional climate variability associated with the effects of solar output on the ocean and atmosphere should be taken into account when making future climate projections.
Notes for Editors:
Funding for this research has come from the Natural Environment Research Council, UK, the National Science Foundation, Switzerland, the European Commission and NCAR’s Computational and Information Systems Laboratory (CISL). This research forms part of the Climate Change Consortium of Wales (C3W; http://c3wales.org/).
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The paper:
Solar forcing of North Atlantic surface temperature and salinity over the past millennium
Paola Moffa-Sánchez, Andreas Born, Ian R. Hall, David J. R. Thornalley & Stephen Barker
Nature Geoscience (2014) doi:10.1038/ngeo2094
Abstract:
There were several centennial-scale fluctuations in the climate and oceanography of the North Atlantic region over the past 1,000 years, including a period of relative cooling from about AD 1450 to 1850 known as the Little Ice Age1. These variations may be linked to changes in solar irradiance, amplified through feedbacks including the Atlantic meridional overturning circulation2. Changes in the return limb of the Atlantic meridional overturning circulation are reflected in water properties at the base of the mixed layer south of Iceland. Here we reconstruct thermocline temperature and salinity in this region from AD 818 to 1780 using paired δ18O and Mg/Ca ratio measurements of foraminifer shells from a subdecadally resolved marine sediment core. The reconstructed centennial-scale variations in hydrography correlate with variability in total solar irradiance. We find a similar correlation in a simulation of climate over the past 1,000 years. We infer that the hydrographic changes probably reflect variability in the strength of the subpolar gyre associated with changes in atmospheric circulation. Specifically, in the simulation, low solar irradiance promotes the development of frequent and persistent atmospheric blocking events, in which a quasi-stationary high-pressure system in the eastern North Atlantic modifies the flow of the westerly winds. We conclude that this process could have contributed to the consecutive cold winters documented in Europe during the Little Ice Age.
Mohatdebos says:
March 10, 2014 at 1:56 pm
… I find it interesting that 17-18 years of no warming is considered a temporary phenomena, but an almost equal length period of warming is considered permanent.
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Many of us wonder the same thing.
Mathew Marler asked:
“Is it not at least as likely that the global effects of small TSI changes have been underestimated?”
Direct effects, no. The change in simple TSI is too small as Leif often points out.
Indirect effects, yes, because the global air circulation patterns appear to change with changes in solar activity. The above paper makes a start in recognising that fact but ignores the similar changes in the southern hemisphere during the LIA.
I have proposed a plausible mechanism involving ozone which changes global cloudiness and then alters the proportion of TSI able to enter the oceans to drive the climate system.
That produces a large enough amplification of the solar changes to produce the variations observed over the past several thousand years.
@ur momisugly Latitude: “…less than zero.” Yes.
Perhaps, I was wrong. It appears that Dr. Svalgaard DOES support AGW by that comment (emphasizing “much smaller”). Aaack. I don’t want to think that!
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Dear Dr. Svalgaard,
Would you please do many of us who highly value your thinking a favor? We need to hear from you that you agree that the null hypothesis re: human CO2 as a climate driver is NOT DISPROVEN. I say “need” to hear because it would put many a WUWT mind at ease.
Your somewhat perplexed (but hopeful!) student,
Janice
P.S. I’ll assume the answer to my Q to you (re: my post of 2PM today)
is, essentially, “Poor.”
<(:(] Well, thanks for giving me the courtesy of not saying it out loud (smile).
@ur momisugly Grumpy (2:33) LOL — Yes, and heavy on the “thick.” As a brick!
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They’ve been out in the Sun too long?
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I sometimes wonder if the terminology changed from “Global Warming” to “Climate Change” because “they” noticed the temps weren’t rising or if ‘they” didn’t really expect they would but didn’t want the Gravy Train (“Power Train”?) to be derailed.
Interesting that in the abstract there is no mention of AGW. One might surmise that the AGW language was added during peer review/editorial – would love to see the article as originally submitted.
Did they bother to mention what they assume to be the effects of CO2 ?
I think it would be useful to perhaps read the entire thing and take it in before jumping to conclusions about this study!
Its focus on solar activity and its affect on ocean temperatures and localized climate, introduces some new and interesting approaches to the study of climate. As has been noted repeatedly here and in other places, many models and studies tend to overlook or underplay, cooling mechanisms, and this has clearly resulted in models running too hot. So I welcome this kind of study that begins to offer outlines based on actual study of the oceans and documented temperatures.
At last it seems that climate science is starting to look in the right area as to the causes of climate change in the NH. Because l now think its the change and movement of the Azores high in the North Atlantic is what is key to major climate change in the NH.
As am now getting convinced that its the current strong and fairly stable Azores high is what blocks the NH off from entering into a ice age.
“The study found that changes in the Sun’s activity can have a considerable impact on the ocean-atmospheric dynamics in the North Atlantic, with potential effects on regional climate.”
So they claim to have identified a climate response to solar variability, but then –
“Predictions suggest a prolonged period of low sun activity over the next few decades, but any associated natural temperature changes will be much smaller than those created by human carbon dioxide emissions”
Given CO2 has no ability warm an atmosphere exhibiting vertical circulation, this would mean that the solar effect they claim to have identified is less than nothing. Not sure how that works…
Maybe, after the warm turns, a congressional investigation could delve into this matter. Sociologists of science would be eager to offer assistance. Participation could — at first, anyway — be voluntary. But clamming up would look suspicious.
https://archive.org/details/our_mr_sun
thanks all i knew you were right all along for years I’ve being saying this on my radio show in vancouver lost a few listeners cause I’m a foil head ! thanks one and all
Janice Moore says:
March 10, 2014 at 2:43 pm
Would you please do many of us who highly value your thinking a favor? We need to hear from you that you agree that the null hypothesis re: human CO2 as a climate driver is NOT DISPROVEN
I don’t like double negatives. For me the issue is this:
x% is due to solar activity and related
y% is due to man [CO2, land use, manipulation of data]
z% is due to random fluctuations of a complex non-linear system [e.g. ocean related]
w% is due to long-period cycles [e.g. due to orbit changes or solar energy production]
We do not know what x, y, z, and w are. To assume that any one of them is 100% is silly, so they are likely all rather small. If we assume they are equal, that gives us 25% for each which to within a factor of 2 sounds reasonable.
You are arguing over such a small percentage of the atmosphere that is meaningless – the percentage of CO2 is small and the human contribution is so small that it is meaningless in the chemistry of climate – it can however improve plant growth.
Silly to argue about FEELINGS ND NOT SCIENCE.
Soooo … the Sun’s variability is hiding the man made global warming, but the global warming is not due to the Sun’s activity – that can only cool the planet.
rogerknights: [Sociologists of science would be eager to offer assistance. ]
That will be an interesting study, some day: “The Sociological Distortion of Climate Science during the AGW Fiasco of 1990-2020”. I just hope that the evidence is being preserved.
To me this paper seems to ascribe large changes in Earth’s climate to fluctuations in solar output, and, surprisingly, it seems to explain historical weather for a long period, at least as much as climate. Then, as if to calm everybody down, they say that of course any of these changes are small relative to CO2 forcing. It could be that the last assertion may have been tacked on to ensure publication.
Or maybe I’m just hallucinating.
Robert of Ottawa says:
March 10, 2014 at 3:39 pm
but the global warming is not due to the Sun’s activity – that can only cool the planet.
Solar activity if high enough [e.g. by a 1000 times] can certainly warm the planet. Your ‘only’ is a misconception.
Leif, you highlighted the wrong words in the conclusion; here is my versions:
“Despite the hemispheric temperature changes expected from solar minima being much smaller than the warming from future CO2 emissions, regional climate variability associated with solar-induced ocean-atmosphere feedbacks could be substantial and should be taken into consideration when projecting future climate changes.”
In other words, they have untested assumptions and a complete lack of evidence, AKA. numbers, data etc. This is just hand-waving BS.
Another, rather clumsy attempt to sneak in AGW propaganda behind a veneer of “real” science. I am not deceived.
And yes, the historical record DOES point to the Sun being the primary drive of climate, versus no correlation or evidence whatever that CO2 has a discernible effect.
We won’t be out of the woods with these mollusks until CAGW is dead and buried once and for all.
Dear Dr. Svalgaard,
Re: “We do not know what x, y, z, and w are.”
Thank you.
Janice
But if blame the Sun we can’t buy more oceanside houses, 100ft houseboats and Gulfstream jets for Al Gore!!
lsvalgaard @ur momisugly March 10, 2014 at 3:46 pm
Solar activity if high enough [e.g. by a 1000 times] can certainly warm the planet. Your ‘only’ is a misconception.
I wrote that in a fit of rhetoric,. You are correct.
“can led to regional climate variability, and the study findings matched historic accounts of climate change, including the notoriously severe winters of the 16th and 18th centuries which pre-date global industrialisation.”
%3Bhttp%253A%252F%252Fwww.swisseduc.ch%252Fglaciers%252Fglossary%252Flittle-ice-age-two-en.html%3B700%3B450
Although I think the paper is squeezing too much out of these much-abused little shells, I welcome the historical references. I think it would be a good idea for Anthony to have a section on historical climate (probably include paleoclimate as a sub group.
Shakespeare writ during the LIA
Let us see what he doth say:
From Act II, Scene 7 in As You Like It:
http://allpoetry.com/poem/8449737-Blow–Blow–Thou-Winter-Wind-by-William-Shakespeare
Then there are the paintings:
By Berman: compare his painting to recent photo showing level of glacier:
By Hendrik Averkamp:
http://www.schillerinstitute.org/educ/reviews/2010/james_ice_age.html
And loads more. It’s also a nice artsy counterpoint to bloodless graphs and equations and yet it is also hard data.
Hobby Hunter.
There is no doubt that if a large portion of the population walked around with tinfoil on their heads, more evil solar radiation will be reflected back into space, thus saving the planet.
There is method to the Warmista madness.