Response From Nicola Scafetta On His New Paper on Astronomical Oscillations and Climate Oscillations.

Roger A Pielke Sr asked me to respond to a comment sent to him by Gerhard Kramm of the University of Alaska on my recent paper

N. Scafetta, “A shared frequency set between the historical mid-latitude aurora records and the global surface temperature” Journal of Atmospheric and Solar-Terrestrial Physics, in press. DOI: 10.1016/j.jastp.2011.10.013.

Kramm’s final argument is that “Since the sunspot number may be considered as an indication for the sun’s activity, this weak correlation does not notably support Scafetta’s hypothesis.”

I believe that Dr. Kramm may be not really familiar with the topics addressed in my paper. The issue is complex and I will try to respond, but only a detailed study of my papers and of the relevant scientific literature can fully satisfy an interested reader.

In brief, Dr. Kramm argument is based on a total solar irradiance model based on the sunspot number record proposed by Schneider and Mass in 1975, that is 36 years ago! This proxy reconstruction claims that solar activity is practically constant plus a 11-year cycle. Because such a reconstruction does not resemble the temperature record in any way, Kramm concluded that it does not support Scafetta’s hypothesis.

I fully agree with Kramm that the solar irradiance reconstruction proposed by Schneider and Mass in 1975 does not support my hypothesis. However, Kramm did not appear to have realized that the solar irradiance reconstruction proposed by Schneider and Mass in 1975 is considered today to be severely obsolete.

Reconstructing the past total solar irradiance is not an easy task: there exists only proxy reconstructions not direct measurements. What people today know is that the sunspot record by alone is not an accurate representation of the solar activity and of the heliosphere dynamics.

The figure below shows some of the total solar irradiance reconstructions proposed during the last 15 years. Other records exist.

Figure:  Several proposed total solar irradiance (TSI) proxy reconstructions. (From top to bottom: Hoyt and Schatten, 1997; Lean, 2000; Wang et al., 2005; Krivova et al., 2007.)

As it is evident from the figure, different models have produced different solar irradiance reconstructions. And all of them differ from Schneider and Mass’ model adopted by Kramm to criticize my paper.

Even the total solar irradiance records obtained with satellite measurements are not certain. At least two possible reconstructions have been proposed: the PMOD (top) and the ACRIM (bottom) TSI satellite composites.


In my past papers I have analyzed the relation between some of the above reconstructions and the climate records in great details and what I got, for example in

N. Scafetta, “Empirical analysis of the solar contribution to global mean air surface temperature change,” Journal of Atmospheric and Solar-Terrestrial Physics 71 1916–1923 (2009), doi:10.1016/j.jastp.2009.07.007.

is summarized in the following figure


The figure shows the climate signature of the solar component alone against a reconstruction of the climate since 1600. Since 1980 I am adopting TSI reconstructions based on ACRIM and PMOD. The matching with the climate records is quite good for 400 years which includes the last 40 years if we use the ACRIM TSI composite. The temperature, though, presents an additional 0.2-0.3 oC warming that is probably the real net anthropogenic contribution (GHG+Aerosol+UHI+LUC+errors in combining the temperature records, etc) since 1900.

The figure above shows that the climate is mostly regulated by solar changes. However, the matching is not absolutely precise. The reason, in my opinion, is that the TSI proxy reconstructions proposed are not sufficiently accurate yet and there may be additional natural forcings.

So, in my more recent papers I have studied the oscillations of the solar system regulated by planetary orbits which very likely are the first cause external forcings acting on the sun and the heliosphere. Very likely, the Sun and the heliosphere oscillate in the same way and the Earth’s system will likely resonate with those oscillations too.

In my recent paper

N. Scafetta, “Empirical evidence for a celestial origin of the climate oscillations and its implications”. Journal of Atmospheric and Solar-Terrestrial Physics 72, 951–970 (2010), doi:10.1016/j.jastp.2010.04.015

I address the above issues and I found that indeed the climate system is characterized by the same oscillations found in the astronomical oscillation driven by planetary and lunar harmonics with major periods at 9, 10-10.5, 20 and 60 years.

In my latest paper

N. Scafetta, “A shared frequency set between the historical mid-latitude aurora records and the global surface temperature” Journal of Atmospheric and Solar-Terrestrial Physics, in press. DOI: 10.1016/j.jastp.2011.10.013

I show that also the mid-latitude historical aurora records since 1700 are characterized by the same frequencies of the climate system and of the planetary system with major periods of 9, 10-10.5, 20 and 60 years. The mid-latitude historical aurora records represent a direct observation of what was happening in the ionosphere and give us an information complementary to the one that can be deduced from the sunspot record alone. The mid-latitude auroras from Europe and Asia, together with other available records from North America and Iceland reveal an interesting oscillating dynamics: Northern and Southern aurora records, which should be understood relative to the magnetic north pole not the geographical one, present a complementary 60 year cycle, for example, that matches the 60-year cycle observed in the temperature as suggested in the figure below


Figure:   (A) The 60 year cyclical modulation of the global surface temperature obtained by detrending this record of its upward trend shown in Fig.1. The temperature record has been filtered with a 8-year moving average. Note that detrending a linear or parabolic trend does not significantly deform a 60-year wave on a160-year record, which contains about 2.5 of these cycles, because first and second order polynomials are sufficiently orthogonal to a record containing at least two full cycles.  On the contrary, detrending higher order polynomials would deform a 60-year modulation on a 160-year record and would be inappropriate. (B) Aurora records from the Catalogue of Polar Aurora <55N in the Period 1000–1900 from 1700 to 1900 (Krivsky and Pejml, 1988). (B) Also depicts the catalog referring to the aurora observations from the Faroes Islands from 1872 to 1966. Both temperature and aurora records show a synchronized 60-year cyclical modulation as proven by the fact that the 60-year periodic harmonic functions superimposed to both records is the same. This 60-year cycle is in phase with the 60–61 year cycle associated to Jupiter and Saturn: see Figs.6 and 7.

Silverman (1992),

for example, showed the 60-year cycle complimentary pattern in the Faroes and Iceland aurora records in this figure.


 Where the 60-year cycle in the Faroes is negative correlated to the 60 year cycle in the temperature while the 60-year cycle in Iceland is positive correlated to the 60 year cycle in the temperature from 1880 to 1940. The same complementary dynamics exists between the mid-latitude European/Asian auroras (which are explicitly studied in my paper) and the American New England auroras (which occupy a northern region relative to the magnetic north pole despite their geographical latitude) for the 1800-1900 period.

This dynamics suggests harmonic changes in the physical properties of the magnetosphere and ionosphere, and upper atmosphere in general, that appear to be directly linked to astronomical oscillations. That may also suggest a change in the magnetosphere/ionosphere sensitivity to incoming cosmic ray flux, which can regulate the cloud system. Thus, my paper shows that a complex astronomical harmonic forcings of the upper atmosphere very likely exists and very likely alters the electric properties of the atmosphere which are known to be able to regulate the cloud system as discussed by Tinsley and Svensmark.

My hypothesis is that the Earth’s albedo is likely oscillating with the same frequencies that we found in the solar system and the temperature at the surface cannot but follow those oscillations too. In the paper, I show that such hypothesis fits the records that we have showing cycles in the cloud system and in the solar dimming and brightening patterns, also from an energetic point of view.

For example a recent paper by Soon et al. (Variation in surface air temperature of China during the 20th century ASTP 2011, showed  a very good correlation between the 60-year cycle in the temperature record (in this specific case referring to China) and the sunshine duration cover in Japan, which may be due to a cloud cover oscillation.


Figure:  Annual mean China-wide surface air temperature time series by Wang et al. (2001, 2004)  from 1880 to 2004 correlated with the Japanese sunshine duration of Stanhill and Cohen (2008) from 1890 to 2002 (from Soon et al. 2011).

Other references referring to cloud and sunshine oscillations are in my paper which presents a 60-year cycle.

In fact, in my paper I have argued that small oscillations of the albedo equal to 1-2% may induce climate oscillations compatible with the observations.

The final result of my paper is summarized in the following figure


Figure:  Astronomical harmonic constituent model reconstruction and forecast of the global surface temperature.(A) Four years moving average of the global surface temperature against the climate reconstructions obtained by using the function F1(t)+P1(t) to fit the period 1850–2010 (black solid) and the period 1950–2010(dash),and the function F2(t)+P2(t)  to fit he period1850–1950(dots). (B) The functions P1(t)  and P2(t) represent the periodic modulation of the temperature reproduced by the celestial model based on the five aurora major decadal and multidecadal frequencies. The arrows indicate the local decadal maxima where the good matching between the data patterns and the models is observed. Note that in both figures the three model curves almost coincide for more than 200 years and well reconstruct and forecast the temperature oscillations.

The figure clearly shows that my harmonic model based on astronomical/lunar cycles, which is depicted in full in B, can reconstruct and forecast with a good accuracy the observed climate oscillations. For example, in B the harmonic model is calibrated during the period 1850-1950 and then it is shows to forecast the climate oscillations (in red) observed from 1950 to 2011. The model is also calibrated during the period 1950-2011 and it is shown to forecast the climate oscillations from 1850 to 1950. The upward trend in A in part produced by the longer solar trending as shown in a figure above and has not been added to the harmonic model yet. Indeed, by looking at the forecasting results in the above figure B I need to say that they perform far better than the IPCC general circulation models, which have never succeeded in forecasting anything.

Of course, I do not claim that my last papers respond to all questions and all related issues. On the contrary, many issues emerge and remain unexplained. This is perfectly normal in science, which is full of mysteries that wait to be explained. Also, my harmonic model may require other frequencies, for example the ocean tides are currently predicted with 35-40 harmonic constituents, while I used only four frequencies in my current model.

However, the merit of my present work, I believe, is to stress the importance of the natural variability of the climate, which has been mostly ignored by the IPCC 2007 modeling, and to show that climate variability is made of an important harmonic component very likely linked to astronomical oscillations and, therefore, the climate can in principle be forecast within a certain limit.

Also an anthropogenic component appears to be present, of course, but because the IPCC models do not reproduce the climate natural variability, those models have significantly overestimated the anthropogenic component by a very large factor between 2 and 4, as explained in my papers. This indirectly implies that the IPCC warming projections for the 21st century need to be reduced by a corresponding large factor. Moreover for the next 30 year the climate may remain steady instead of warming at the rate of 2.3 oC/century as predicted by the IPCC. Longer forecasts may require the addition of longer cycles not yet included in the current work. 

About the criticism of Dr. Kramm based on Schneider and Mass work in 1975, that is a 36-year old work, I cannot but stress that it is based on a severely poor understanding of the present knowledge. Indeed, Dr. Kramm does not seem to have spent much time reading the relevant scientific literature since 1975 and, in particular, my papers with their numerous references. It is evident that it is inappropriate criticize a work without even reading it or trying to become familiar with its topics and arguments which go far beyond the sunspot number record alone. But, apparently, not everybody understands such an elementary logic.

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