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.
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.
I’ll take actual temp measurements along with solar activity observations over “computer-based models of past climate”.
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.
what was it Einstein said?
A wop bop a loom op a lop bam boom?
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.
Sun not involved in climate new NGO funded study says.
Everyone should try and read Paul Pierett’s paper above.
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.
The key word was “models”. GIGO
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.
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
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
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..
“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.
I guess, based on this study, we have nothing to fear when our sun goes super-nova.
NERC or NDRC? Which funded the study?
Sorry – NRDC…