Claim: Solar activity not a key cause of climate change, study shows

From the University of Edinburgh , another one-paper syndrome in the making funded by an NGO research council with a political mission to grab a headline. And, another poorly written press release where they don’t even cite the name of paper. Sigh.

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Climate change has not been strongly influenced by variations in heat from the sun, a new scientific study shows

Climate change has not been strongly influenced by variations in heat from the sun, a new scientific study shows.

The findings overturn a widely held scientific view that lengthy periods of warm and cold weather in the past might have been caused by periodic fluctuations in solar activity.

Research examining the causes of climate change in the northern hemisphere over the past 1000 years has shown that until the year 1800, the key driver of periodic changes in climate was volcanic eruptions. These tend to prevent sunlight reaching the Earth, causing cool, drier weather. Since 1900, greenhouse gases have been the primary cause of climate change. 

The findings show that periods of low sun activity should not be expected to have a large impact on temperatures on Earth, and are expected to improve scientists’ understanding and help climate forecasting.

Scientists at the University of Edinburgh carried out the study using records of past temperatures constructed with data from tree rings and other historical sources. They compared this data record with computer-based models of past climate, featuring both significant and minor changes in the sun.

They found that their model of weak changes in the sun gave the best correlation with temperature records, indicating that solar activity has had a minimal impact on temperature in the past millennium.

The study, published in Nature GeoScience, was supported by the Natural Environment Research Council.

Dr Andrew Schurer, of the University of Edinburgh’s School of GeoSciences, said: “Until now, the influence of the sun on past climate has been poorly understood. We hope that our new discoveries will help improve our understanding of how temperatures have changed over the past few centuries, and improve predictions for how they might develop in future. Links between the sun and anomalously cold winters in the UK are still being explored.”

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I’m not so sure this fellow is fully versed on climatology. His papers up to 2011 were all about cosmology, then all of the sudden he starts publishing on climatology issues. One wonders if his previous funding dried up to make such a dramatic shift in study. Then there is: “…climatic fingerprints of high and low solar forcing derived from model simulations…”. IPCC Models haven’t been able to reproduce the last ten years; what makes them think they are worth anything 100-200 years ago?

Here is the abstract:  http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2040.html

Small influence of solar variability on climate over the past millennium

Nature Geoscience (2013) doi:10.1038/ngeo2040
Received 02 August 2013 Accepted 14 November 2013 Published online 22 December 2013

The climate of the past millennium was marked by substantial decadal and centennial scale variability in the Northern Hemisphere1. Low solar activity has been linked to cooling during the Little Ice Age (AD 1450–1850; ref.  1) and there may have been solar forcing of regional warmth during the Medieval Climate Anomaly2, 3, 4, 5 (AD 950–1250; ref. 1). The amplitude of the associated changes is, however, poorly constrained5, 6, with estimates of solar forcing spanning almost an order of magnitude7, 8, 9. Numerical simulations tentatively indicate that a small amplitude best agrees with available temperature reconstructions10, 11, 12, 13. Here we compare the climatic fingerprints of high and low solar forcing derived from model simulations with an ensemble of surface air temperature reconstructions14 for the past millennium. Our methodology15 also accounts for internal climate variability and other external drivers such as volcanic eruptions, as well as uncertainties in the proxy reconstructions and model output. We find that neither a high magnitude of solar forcing nor a strong climate effect of that forcing agree with the temperature reconstructions. We instead conclude that solar forcing probably had a minor effect on Northern Hemisphere climate over the past 1,000 years, while, volcanic eruptions and changes in greenhouse gas concentrations seem to be the most important influence over this period.

Figure 1: Simulations and temperature reconstructions.

Simulations and temperature reconstructions.

a, Simulations with all forcings (red and green) compared with a reconstruction ensemble14 (blue), and instrumental HadCRUT4 (ref. 24) time series (centred on the average reconstruction over time of overlap, black).

The SI is here: http://www.nature.com/ngeo/journal/vaop/ncurrent/extref/ngeo2040-s1.pdf

h/t to Dr. Leif Svalgaard

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Dear Anthony,
My research is linked below. My research is quite contrary to the article.
http://sunspotshurricanesandglaciers.com/files/74034647.pdf
Most Sincerely,
Paul Pierett

one paper wonder?
what was it Einstein said?
REPLY: I’ll remind you of what you said to me at AGU discussing Robert Rhode’s poster. “models aren’t proof of anything, they are simply best guesses”. So here we have modeled (not observed) solar activity being curve fit to observed surface temperatures. I’m pretty sure Einstein would not be impressed. – Anthony

I’m not so sure this fellow is fully versed on climatology.?
hmm. are you talking about Ross mcKittrick? Steve McIntyre?
Check the other authors. The third is rather well known.

rob m.

I’ll take actual temp measurements along with solar activity observations over “computer-based models of past climate”.

Peter Miller

I note that these guys have a forcing impact for today’s CO2 levels of 1.5Wm2, which is just a little less than the change in the Sun’s measured irradiation over its 11 year cycle.

I wander what volcanoes caused the LIA.
That was a 150 years stretch of mighty volcano activity…

I love the logic here. (Not)
First they assume a cause. (Volcano’s)
Then, they define “climate change” in such a way that it only includes changes which can be attributed to the cause that they have already chosen.
Then they write up a study, and claim that this study “Proves” that they have invalidated all other sources of “climate change”, in favor of their pre-selected “cause”.
brilliant, I suppose, but only for those who are impressed by academic gamesmanship.
You note that his previous work was on cosmology. I humbly suggest that Dr Andrew Schurer’s time would be put to far more productive us in the future if he focused on cosmetology; at least he might have a chance of turning out something productive.

Martin A

what was it Einstein said?
A wop bop a loom op a lop bam boom?

Rob

I’m Rob M too and I was just about to say that.
They are “fitting” sun activity to models rather than finding correlation between sun activity and realty.

Kaboom

Sun not involved in climate new NGO funded study says.

JimS

Everyone should try and read Paul Pierett’s paper above.

RicHard.

I was about to have a look at this paper below, guess no need to now.
Paper finds solar activity explains climate change over past 200,000 years
A paper published in Earth and Planetary Science Letters finds solar activity was strongly correlated to climate change over the past 200,000 years. The paper reconstructs solar geomagnetic field strength using the 10Be isotope proxy of cosmic rays, which is inversely related to solar activity. The reconstruction in Figure 2 shows solar activity at the end of the record [“near present day”] was at some of the highest levels of the past 200,000 years, and solar geomagnetic field intensity approximately 3 times higher than during the ice age ~180,000 years ago.

Gerald Machnee

The key word was “models”. GIGO

A C Osborn

Surely this sentence does not make sense
“They found that their model of weak changes in the sun gave the best correlation with temperature records, indicating that solar activity has had a minimal impact on temperature in the past millennium.”
This part
“They found that their model of weak changes in the sun gave the best correlation with temperature records”
does not match this part
“indicating that solar activity has had a minimal impact on temperature in the past millennium.”
Is it incorrectly reported?

Stephen Mosher says “Check the other authors. The third is rather well known.” Indeed, she is a well known alarmist. See climategate.

F.A.H.

The key paragraph explaining what they do seems to be the following:
“To resolve whether solar forcing is a large or small contributor to Northern Hemispheric mean temperatures, we estimate the magnitude of the response to solar and other forcings directly from temperature reconstructions. We do this by deriving a decadally smoothed (see Supplementary Information) fingerprint of expected change for Northern Hemispheric SAT from each model ensemble that is driven by a particular external forcing (for example, solar). The magnitude of this fingerprint is then estimated for each reconstruction, accounting for uncertainty both in the magnitude of the forcing and the sensitivity to forcing. This is done by scaling factors that are determinedby minimizing the difference between the reconstruction and a linear combination of fingerprints, using total least squares (TLS) regression15 (Methods). Therefore, we do not need to explicitly investigate different forcing amplitudes.”
Which basically means they picked some models that did what they wanted ran some simulations, and then regressed the heck out of it until they got what they wanted. Later in the paper they discuss how they did different analyses on different subsets of the “data” (i.e. different time periods of reconstructions based on the data) to extract various pieces of information. The paper will provide an excellent example for undergraduate science courses in the dangers of too readily available regression packages and the need to make minimal assumptions when doing statistical analysis.

Some of the problems with this paper:
1. They use a conventional climate model which does not consider any of the many solar amplification mechanisms described in the literature.
http://hockeyschtick.blogspot.com/search?q=solar+amplification+mechanism
2. They switch datasets used for solar forcing from Steinhilber et al to Wang et al in the year 1800. If they had maintained consistency and used Steinhilber all the way through the year 2000, there would have been greater solar forcing at the end of the 20th century.
http://hockeyschtick.blogspot.com/2013/04/new-paper-predicts-sharp-decline-in.html
3. They don’t consider accumulated solar energy/time integral of solar activity, which can explain 95% of climate change over the past 400 years.
http://hockeyschtick.blogspot.com/2013/11/the-sun-explains-95-of-climate-change.html
RicHard. says: December 23, 2013 at 9:58 am
I was about to have a look at this paper below, guess no need to now.
Paper finds solar activity explains climate change over past 200,000 years

Suggest you still have a look – the paper makes a strong case that glacial-interglacial cycles are primarily due to changes in solar activity, not Milankovitch Cycles, which suffer from the so-called 100,000 year problem.
http://hockeyschtick.blogspot.com/2013/12/paper-finds-solar-activity-explains.html

Sweet Old Bob

I think I am pressing that large red button. No, not the one that says EASY.
The other one…

Steven Mosher says:
December 23, 2013 at 9:48 am
>> I’m not so sure this fellow is fully versed on climatology.?
> hmm. are you talking about Ross mcKittrick? Steve McIntyre?
I don’t see them listed as contributors.
> Check the other authors. The third is rather well known.
The third author is a gal, not a fellow, but she is likely well versed, and possibly biased. She was the lead author of a chapter of AR4 WG1, see http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch9.html

Richard M

Sadly they ignore the single most important factor in climate changes … the oceans. From what I can tell solar changes tend to be of shorter duration which is also true of volcanoes. They won’t find great correlations with either one..

Pippen Kool

“His papers up to 2011 were all about cosmology, then all of the sudden he starts publishing on climatology issues. One wonders if his previous funding dried up to make such a dramatic shift in study. Note the “…was supported by the Natural Environment Research Council.” at the end. That alone makes me suspicious of the science presented because it looks a lot like “science for hire” ”
He is a postdoc (which is what Research Associate usually means at that stage of his work); the work before (08) must be grad work, but I couldn’t figure out who his mentor was just from the author lists. It is common and often recommended to slightly switch focus and institution between you grad work and your post doc work.
All postdocs are scientists for hire. Or you don’t eat.
And BTW re cosmology, the sun is a star.

Sorry to see this came out of Edinburgh, not noted for being a hotbed of lunacy under normal circumstances.
As you say Schurer is not exactly noted as a climatologist. Hegerle is and it would be interesting to know why she has linked up with Schurer. Tett is Chair of Earth System Dynamics and Modelling and Head of the Global Change Research Institute as well as being ex-Hadley Centre, so we know where he’s coming from.
Maybe Schurer is the fall guy just as (I still claim!) Mann was for MBH98.

BradProp1

I guess, based on this study, we have nothing to fear when our sun goes super-nova.

Merrick

NERC or NDRC? Which funded the study?

Merrick

Sorry – NRDC…

Jos

As far as I can see the model does not include interactive ozone (i.e. ozone will vary with temperature, atmospheric dynamics and chemistry). Funny enough, although the SI has a section on ozone, the section actually does not say a single thing about ozone. In all honesty, if your model does not have interactive ozone and thus no coupling between changes in ozone and dynamics, I would have a hard time buying that you can say much about the influence of solar variability. Most climate models don’t have interactive ozone, in particular those use for the Paleoclimate Model Intercomparison Project, which is where the results of this study are used for; simulations are generally too long to include complex stratospheric chemistry.

davidmhoffer

Steven Mosher says:
December 23, 2013 at 9:48 am
I’m not so sure this fellow is fully versed on climatology.?
hmm. are you talking about Ross mcKittrick? Steve McIntyre?
>>>>>>>>>>>>>>>>>>
I don’t recall either claiming to be versed in climatology. Their claims have been entirely about the mishandling of data analysis and statistics in climate papers. I don’t need a degree in physics to point out that if a paper is predicated on 2+2=5.39 that it is wrong.
You have a great deal of knowledge to share. It is too bad that you choose instead condescension and misdirection.

Richard Mallett

Looking at the graphs in the Supplementary Information, one sees large decreases in temperature at the time of the Dalton minimum in so many of them. That was a time of low solar activity, right ?

Richard

Hockey Schlick,
I was only joking.

jorgekafkazar

“Scientists [sic] at the University of Edinburgh carried out the study using records of past temperatures constructed with data from tree rings and other historical sources.”
Aha! New frontiers in dildoclimatology.

Necessary assumptions:
1. The overall energy from the Sun is a constant.
2. Variations in Solar Magnetic Fields do not affect the Earth’s climate in any significant way.
3. Solar storms and other solar physical phenomena do not affect the Earth’s climate in any significant way.
4. Pre-industrial global temperature had a constant maximum.
5. After a volcanic eruption-caused temperature drop, global temperature would, over time, return to that constant.
How could this account for Hot House and Ice Age periods in the paleoclimate?

Tonyb

The NREC is a perfectly respectable uk organisation who funds a wide range of environment related science research including the paper under review.
http://www.nerc.ac.uk/
Are they being confused With another organisation?
Tonyb

EternalOptimist

A fact for every occasion?
‘Scientists at the University of Edinburgh carried out the study using records of past temperatures constructed with data from tree rings and other historical sources’
yesterday we were being told that the heat is missing because it goes straight into the deep oceans. Today we are being told that it stays in the atmosphere and affects tree growth.
Which is it ?

Mohatdebos

I apologize if I am misunderstanding the study — I am just an economist with training in econometrics and statistics. It appears they took output from models (curve fitting exercises) that exclude solar as a forcing, correlated that output with estimated temperatures, and find there is no or minimal correlation between the model outputs and the estimated temperatures. Why is that a surprise? The curve fitting probably took care of all the external forcing, leaving no room for additional variables.

catweazle666

Some nice hockey sticks there from Dr. Schurer.
Is he going into business?

Teddi

What is wrong with these people ? Have they lost all common sense ?
Ok then, shut the Sun down and observe how the climate changes…
Idiots !

John Shade

Edinburgh – town and gown – has a lot to be ashamed about in the climate arena. They gave a civic award to James Hansen. They have many academics well ensconsed on the irresponsible, odious bandwagon of climate scaremongering. There is a Royal Society of Edinburgh which is not much better than the one in London where it comes to swallowing, promoting, and eating out on the same sorry platform.

Martin

[snip problem has been corrected see upthread -mod]

Keith A. Nonemaker

The most obvious problem is that they used Mann’s tree-ring based hockey stick as their temperature target. Even if they had hit the bulls-eye, it was the wrong target.

Martin

“funded by an NGO research council with a political mission to grab a headline.”
Which is just Anthony’s opinion which is not backed up by any facts…
http://www.nerc.ac.uk/about/work/policy/openness.asp
[ See this: “NERC’s Science Impacts Database Link to external site includes more than 200 examples of where NERC science has made, or has the potential to make, a political, economic, social or practical impact.” -mod]

john robertson

Perhaps the current down tick in solar activity, is causing some fear in academia.
Models all the way down, using tree thermometers ?
Might have been easier to just MSU as normal for Climatology.
I never expected a so called science would make scientology look respectable.

Stephen Richards

I had to write a thesis on Einstein for my MSc and on Newton for my BSc. Of the two, eistein was the most humble but still suffered from bouts of irrationality. Newton was at times a nasty political animal but a brilliant engineer and scientist. Of the two, my vote goes to Eistein.
Isn’t this uni one of Bouldon’s / Boulton’s of CRU/UEA fame.?

DirkH

The problem for the alarmists with this paper is that we have non-rising temperatures for 17 years and no prominent volcano eruptions. So, the volcano-temperature link does nothing to restore the broken CO2-temperature correlation.

Stephen Richards

Martin says:
December 23, 2013 at 11:17 am
Your fully baggaged mind did not allow you to see the nuance in AW’s writing.

DirkH

Martin says:
December 23, 2013 at 11:17 am
““funded by an NGO research council with a political mission to grab a headline.”
Which is just Anthony’s opinion which is not backed up by any facts…
http://www.nerc.ac.uk/about/work/policy/openness.asp

Thanks for the link. A de facto government body:
http://www.nerc.ac.uk/funding/otherfunding.asp

According to the Edinburgh website, there are two other authors listed:
SJ Phipps
And…………….
ME Mann!
Now who would have guessed that?
http://www.research.ed.ac.uk/portal/en/publications/separating-forced-from-chaotic-climate-variability-over-the-past-millennium%28482bf0e4-c430-4858-830d-ddcb233b1be3%29.html

noaaprogrammer

“Climate change has not been strongly influenced by variations in heat from the sun, a new scientific study shows.”
Well then, I guess that there’s nothing to fear as the sun becomes a red giant!

This article is not worthy , but then again we must keep Leif happy.
Anthony will not and can’t oppose Leif, even though he does not see things the same way.
This site is not balanced and censors so much. Shame on Anthony, who has a good handle on the climate but yields and gives so much longitude to the likes the likes of Leif and others. UGH.
I know you will not post it,(who cares) but I know you got it.
On to the Layman sunspot site, much more balanced.

First those seeking justice must come with clean hands.
So, it seems those who claim solar activity has nothing to do with climate and or climate change should do their research out side, with no air conditioning, and say in Southwestern New Mexico or Southeastern Az. in say August each year for the study of say three years.
Sounds simple, yet what if it in fact is just that simple?