Brief Response To Dr. Gerhard Kramm By Nicola Scafetta

Herein I will give a brief response to Dr. Gerhard Kramm’s response to my first reply to his comment on my latest publication:

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 believe that Kramm is simply missing the point of my argument.

In his reply Dr. Kramm showed a picture prepared by Solanki which for convenience I report below again. 

The above figure clearly shows that the solar record closely matches the temperature record. Similar results are present in numerous papers that I have authored since 2006 and by numerous papers by other authors as well. 

For convenience I show here again one figure discussed in one of my latest works which is similar to Kramm’s figure, that compare the temperature record since 1600 against the empirical temperature signature of the solar forcing alone by taking into account the heat capacity of the climate system, which in Solanki’s figure was not taken into account:  

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.

Both figures clearly suggest that most of the warming observed from the Little Ice Age of the 17th century to recent times can be associated to solar variation alone. As the figure shows, this would be true also for the last decades if the ACRIM total solar irradiance satellite composite is used in the model, given the fact that the ACRIM composite ( ) presents an upward trend from 1980 to 2000 and a downward trend since 2000. The ACRIM pattern may be indicative of a 60-year modulation in the solar activity, which would explain the two 60-year cycles observed in the climate system since 1850.

Of course, I have never claimed that the sun explains 100% of the observed warming since 1900. From the above figures it is evident that about 50-80% of the observed 1900-2000 warming can be related to the Sun, while the leftover may have alternative causes such as anthropogenic GHGs and urban heat island (UHI) and land use change (LUC) effects, where the UHI and LUC contributions may still be present in the data because of the limitations of the mathematical algorithms presently used to filter them out. 

Thus, it is clear that the data show the existence of a very good correlation between solar records and temperature patterns for numerous centuries up to now, as shown in the above two figures. 

Kramm seems to argue that, despite such a good correlation, a strong solar contribution to the observed climate changes needs to be rejected because he claims there is no enough energy in the solar variations to explain the observed climate change.

I am sorry, but I still believe that Kramm is criticizing my works without reading them first.      

In fact, it is overwhelmingly clear in my work that I am arguing about the existence of an ADDITIONAL climate forcing which is related to solar/astronomical changes: a forcing that is not currently included in the climate models adopted by the IPCC. Essentially I am not talking only about a direct solar irradiance forcing, which is the only thing Kramm is thinking about.

My paper makes it overwhelmingly clear that I am referring to an additional solar/astronomical forcing that would directly act on the cloud system through a modulation of the cosmic rays and/or of the electric properties of the top atmosphere. I am referring in particular to the works by Kirkby, Svensmark and Tinsley, as referenced in my paper.

This cloud modulation effect would be mostly modulated by a modulation of the magnetic properties of the heliosphere and magnetosphere (shown below), which can be driven by the solar variation and planetary motion. Indeed, contrary to what many people think, the Earth is not moving in an empty space environment, as the figures below clearly show.


In my paper I show that if this astronomical forcing modulates the cloud system in such a way that the albedo oscillates with amplitude of just 1-2%, this can explain most of the observed climate change also from an energetic point of view. The data show the existence of such modulation in the cloud cover and in the periods of solar dimming and brightening.

Indeed, in my paper I prove that if a solar change is accompanied with equivalent oscillations of the albedo by 1-2%, the climate sensitivity to solar changes would increase by 10 times relative to the climate sensitivity to solar irradiance alone. This would be more than enough to satisfy Kramm’s perplexities. In my paper I also prove that even if the total solar irradiance is perfectly constant, but other related solar forcings cause an albedo oscillation by 1-2%, this too may be sufficient to explain the temperature oscillations.

The exact physics about the mechanisms involved in these phenomena is still unknown. That is probably why Kramm does not find it in his textbooks and current GCM papers. In my opinion, Kramm’s comment suggests that he does not accept the idea that, after all, the science might be still not settled.

Essentially, in my paper I am arguing that the climate on the Earth can be influenced by what is known as Space Weather that alters the electric and magnetic properties of the Earth space environment (shown in the figure below). The Space Weather can be influenced by the Sun and by the planetary motion. The Space Weather then alters the climate by activating a set of mechanisms that slightly modulate the cloud system in such a way that we have periods with a little bit more (less) cloud cover that cause a cooling (warming) at the surface. Because these forcings are quasi cyclical we have a climate that approximately presents the same cycles and patterns that we find in the solar system.


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