Ice-Age 4: Media and Why There is No Prediction of a Mini Ice Age

Published: 9:21 PM GMT on August 17, 2015

Ice-Age 4: Media and Why There is No Prediction of a Mini Ice Age

This blog concludes with another contribution on the Little Ice Age from my colleague Mike Liemohn.

Addendum: Maggie Villiger at The Conversation, sent me a couple of links, including one that actually talks with Professor Zharkova. Also another take on not heading to a mini ice age. end Addendum

With some trepidation, I am going to continue my exploration of The Daily Mail article of scientists warning of a mini-Ice Age. Previous entries are linked at the end. The Daily Mail story was motivated by the scientific presentation Heartbeat of the sun derived with principal component analyses and prediction of solar activity on millennium scale. The paper was presented by Professor Valentina Zharkova. The abstract of this article is reproduced at the end.

In the previous blog, I concluded, “I see no evidence that Professor Zharkova made any reference to the mini ice age.” I argued that press releases and reports by scientific organizations wrapped the mini ice age around their reports of Professor Zharkova’s paper. And, again, from the previous blogs, “These science organizations made it easy for the Daily Mail, a newspaper known for exaggerated headlines and running many stories that are designed to nurture doubt about climate-change science.”

Early on in the excellent comments and discussion in the previous blogs, a link was provided to an interview on Radio New Zealand entitled, UK scientist suggests a mini ice age be upon us. There was a fair bit on back and forth in the comments about this interview.

I have listened to this interview a number of times. My first reaction was that Professor Zharkova was not in her comfort zone during the interview. She even suggested this late in the interview with seeming surprise at the amount of attention the paper had gotten. I did not hear Professor Zharkova, herself, say “mini ice age.” “Mini ice age” was the persistent cadence of the interviewer. Zharkova did mention that there were cold winters during the ‘Maunder minimum’. She, as in previous quotations, said her research offered a possible explanation of the Maunder minimum, and that she are her colleagues were predicting an extended sunspot minimum. Professor Zharkova did not manage, actively, the transition from the interviewer's questions, which made reference to a mini ice age, to her answers. She did state that she was not an atmospheric scientist and had not made calculations about the impact of a sunspot minimum on the Earth. She did make reference to changes being observed across the solar system, and that there might be a link of these changes to solar variability. (IMO, reasonable as conjecture, but not scientifically analyzed in her answer.) I assert that on its own, this interview as presented, still supports the notion that the press (the interviewer in this case) is, primarily, responsible for framing this paper and Professor Zharkova’s research as a mini ice age story.

My original plan for this series was to analyze Zharkova’s research paper and, specifically, any reference in her research to climate science. This was going to be followed by thinking about the relationship between the Maunder minimum and the Little ice age. I am going to give an abbreviated summary of these two issues, here, and decide whether or not to pursue the ice-age theme any more.

In the previous blog I went to the The Web of Science and searched for the papers and citations of “Zharkova, V.” Her papers were all in solar physics, plasma physics, and applied mathematics, her declared fields of expertise. I, then, repeated the search adding the filter of “climate.” No papers were returned in the search. Professor Zharkova has not identified in The Web of Science key words associated with climate and climate change.

A recent, open access paper entitled Probing latitudinal variations of the solar magnetic field in cycles 21–23 by Parker’s Two-Layer Dynamo Model with meridional circulation appears to be the background of the recent conference presentation Heartbeat of the sun derived with principal component analyses and prediction of solar activity on millennium scale. The paper is observationally based and used observations of the solar background magnetic field measured from the Wilcox Solar Observatory. The observed data are analyzed with principal component analysis, a standard approach to extract correlated behavior. For example, how does variability in one place relate to variability in another place? Principal component analysis is widely used in climate and weather science, for example, how does variability in the Pacific Ocean influence weather in the United States? Once a relationship is found, researchers often seek either physical or statistical models to examine or explain the correlated behavior. In this case they rely on a model by E. N. Parker described in A solar dynamo surface wave at the interface between convection and nonuniform rotation. I note, a 2014 abstract at the 40th COSPAR Meeting that is part of the progression of this research: Principal Component Analysis of Solar Background and Sunspot Magnetic Field in cycles 21-24 and its implications for the solar activity prediction in cycles 25-27.

I am not expert enough to evaluate this research and place it in the context of current research on solar physics and variability on decadal and century scales. However, I am able to conclude that the research approach seems well posed and progressing. It is pretty exciting to be able to describe the magnetic field variability, with the possibility that the sunspot cycles can be derived from this behavior. Again, it is perhaps courageous, but totally appropriate, to make a prediction based on the model. In these papers, I see no mention of climate and climate change. I also note from Probing latitudinal variations of the solar magnetic field in cycles 21–23 by Parker’s Two-Layer Dynamo Model with meridional circulation, “We are fully aware that the model used in the current study is a very simple one, which, nonetheless, allows us to test our understanding of the physical processes responsible for the magnetic field generation during solar activity cycles that can lead to some essential modifications of more sophisticated models, which simulate the solar activity in much more detail.”

With that, let’s make the transformation to climate and climate change and the mini ice ages. First, consider the sophistication and the hierarchy of the models (climate versus solar variability), and how well they have been tested. Second, consider the completeness of observations in terms of the length of the observational record and the ability to make 4-dimensional observations (3 spatial dimensions and time). Is there any knowledge-based foundation on which to hold, even, the conversation about whether or not Zharkova’s research provides substantial uncertainty about the robustness of the observations and projections of global warming due to increasing carbon dioxide? No.

Next consider the Little Ice Age. The present state of the knowledge is that the onset of the Little Ice Age, in the late 1200s, was caused by volcanism and sea-ice ocean feedbacks. Note that this is 200 years before the Maunder minimum. If we examine the energy balance and timing, we find that the Maunder minimum occurred during the Little Ice Age, perhaps had a discernable effect on temperature, but did not cause the Little Ice Age. Also, there are many profound differences between now and the Little Ice Age, notably: a more than 30% increase in the amount of carbon dioxide, vast reductions of northern hemisphere sea ice, and large changes in the land-surface characteristics.

I will end with another contribution from Mike Liemohn, my solar physicist colleague. This one describes his class on Solar-Terrestrial relations.

Student Projects Reject the Hypothesis Linking the Maunder Minimum to the Little Ice Age

Mike Liemohn here again, a space scientist in the same department as Dr. Rood at the University of Michigan, with a second installment on why I don't think Earth is headed toward an Ice Age. This time, I'm going to tell a story about how students have (repeatedly) demonstrated, to themselves and to me, that a few weak solar cycles will not cause temperatures here on Earth to plummet.

I teach an undergraduate class called "Solar-Terrestrial Relations." No, it is not a political science course of how stars and planets get along, but rather a science course of how our Sun works and how it influences the Earth system. It is the first of our undergraduate series towards our Space Science and Engineering degree, but we actually require it of our Climate and Meteorology students as well. The class is divided into three segments: the Sun, near-Earth space, and the Sun-climate connection. It is partly conceptual, learning the relevant phenomena at an intuitive level, partly mathematical, introducing and solving the basic equations governing those phenomena, and partly analytical, spending a class session each week in a computer lab examining data and conducting quantitative assessments of the relationships.

I have the students do an end-of-term project in this course, which can either be an analysis of a space weather event or an assessment of some aspect of the Sun-climate connection. These project options include, among a long list, analyzing the relationship between the Maunder Minimum, when sunspot activity took a 70-year hiatus in the 1600s, and the Little Ice Age, a period of relative cooling in northern Europe in the 1400s to 1800s. Because the Maunder Minimum occurred in the middle of the Little Ice Age, some have postulated that the reduced solar activity contributed, perhaps dominantly, to the cooling trend on Earth.

A student will pick this project option just about every year. So, not only have I done my own literature search on this topic to present in class some basic facts about the Maunder Minimum and Little Ice Age, but also I have seen a string a students dive into the numbers, calculating correlations, frequency power spectral densities, and other analytical assessments of the relationship of Earth's global and regional temperature time series to estimates of the Sun's total solar irradiance output for this interval.

The students, invariably, find that there is no connection between the Maunder Minimum and the Little Ice Age. The cooling interval is just too long, the timing of temperature maxima and minima within the interval do not align with the solar inactivity, and the global nature of the solar input change cannot be reconciled with the regional nature of the cooling on Earth. The influence of a weak sunspot cycle on the Sun just doesn't translate into a very big influence on total solar irradiance, TSI, and therefore doesn't translate into a big influence on Earth's temperature. Other factors caused the Little Ice Age in northern Europe a few centuries ago, like increased volcanic activity or a decrease in atmospheric carbon dioxide due to reforestation after large-scale plagues wiped out portions of humanity. Whatever the primary cause, the Sun played at most a secondary role in the Little Ice Age, and even then, for only part of this cooling interval.

Thank you, Mike.

OK … Science-based knowledge does not support a link between Zharkova’s presentation and a mini ice age. I conclude that the primary link between Zharkova’s presentation and the Earth’s climate comes from a press release by the Royal Astronomical Society. Though Professor Zharkova gets a bit entangled in a discussion of a mini ice age in this radio interview, she does not come across, to me, as a scientist predicting a mini ice age. She has predicted, based on her research, a Maunder minimum type event, and it will be important if this prediction comes true. However, there will not be a mini ice age, and there is no rational or responsible way to hedge on the projections about the Earth’s surface warming, ice melting, sea level rising, and the weather changing.

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Links to earlier in series

Ice-Age 1: There’s a Mini-Ice Age Coming? Good Timing!

Ice-Age 2: Weak Sun Will Not Cause Ice Age (from Mike Liemohn)

Ice-Age 3: The Perils of Science and the Media



My analysis of Professor Zharkova’s scientific work was to reveal the tactics of those trying to discredit climate-change science. I see no evidence that Professor Zharkova made any reference to the mini ice age. I apologize if I cause any grief for her with this blog.

Of interest:

News about an Imminent Mini Ice Age is Trending – but It Is Not True

In the spirit of scholarship and to support other entries in this series. The Daily Mail story relies largely on the research of Professor Valentina Zharkova. Here is the abstract of the Professor’s Zharkova’s talk at the Royal Astronomical Society’s National Astronomy Meeting 2015. Here is a link to Professor Zharkova’s web page at University of Northumbria in New Castle, U.K.. Professor Zharkova is a Fellow of the Royal Astronomical Society (FRAS). I reproduce the abstract of the talk below.

Abstract of the Professor’s Zharkova’s talk

Heartbeat of the sun derived with principal component analyses and prediction of solar activity on millennium scale


In this talk we present new results of principal component analysis of the solar background magnetic field and sunspot magnetic field measured in the cycles 21-24 by Wilcox Solar Observatory and SOHO/MDI. We report a pair of principal components (PCs) of magnetic field waves covering more than 30% of the data variance and attribute these components to dynamo waves generated in two layer dynamo model. We derive mathematical laws describing these dynamo waves and describe their link to the solar activity index of sunspot numbers. Using the derived laws we predict the solar activity backward and forward for two millenniums and reveal close fit to all the observed activity features and the presence of a long-term activity cycle of 320-400 years in addition to the regular 22 year cycle. Preliminary interpretation of the PCA results with the modified Parker's two layer dynamo model accounting for both cycles (22 and 350 years) is also discussed.

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About The Author
I'm a professor at U Michigan and lead a course on climate change problem solving. These articles often come from and contribute to the course.

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Addendum and Update: Please note that in the comments of this blog, it is quickly revealed that Professor Zharkova has, in fact, made links of her research to the little ice age. The primary reference is to a radio interview. More to follow. I knew this was perilous when I wrote it. Rood 20150803


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