The fact that the latest sunspot cycle is very weak has gotten lots of news lately. Many are claiming that a lack of sunspots will cause the Earth to cool in the near future. I am going to stand alone as a skeptic and say I am not convinced. The data simply does not support that conclusion. I am going to explain why I do not believe the prediction that low solar activity (as measured by low sunspot counts) will cause a reversal in the warming trend.
I am going to start off with the basic chart showing the average monthly sunspot count since 1749.
Timing is everything. The timing of the sunspots is critical for this analysis. The best theory for sunspots changing the climate is that higher sunspots prevent cosmic rays from nucleating cloud formation. So an increase in sunspots will reduce cloudiness which will increase temperature. A reduction in sunspots will increase cloudiness which will decrease temperature.
Here is the HadCRU3 temperature since 1850.
What isn’t clear is the problems with the timing that are present. Certainly sunspots in the past 60 years have been higher, but the sunspots were highest in 1960 and the temperature has been highest in the past decade. Nor does a significant time delay explain the problem. The temperature simply does not appear to be overly dependent on the sunspot count.
Since 1993 the sunspot count has not been significant. Certainly in the past 18 years there has been no reason from sunspots to explain the elevated temperatures. Even before then the timing does not indicate a cause and effect relationship. I am going to zoom in on a 100 year period from 1880-1980.
Until the very end of the period, the highest temperature took place in the 1940’s. Sunspots did increase prior to temperature there, but 1917 sunspot peak was comparable to the 1937 peak, but the temperature was not. After the peak temperature in the 1940’s, the temperature dropped for the next 30 years while that same 30 year period experienced the highest sunspot activity that has ever been recorded.
In a very general sense the temperature of the Earth has been higher lately and sunspot activity has been higher over the past 70 years, but there is no clear indication that sunspot activity has a predictable influence on the Earth’s temperature. That the Earth was cold during the Maunder Minimum, but all indicators are that it was even colder during the 1500’s when solar activity was not low like it was in the 1600’s.
There has been on big solar activity reconstruction by Solanki in 2004. I have also compared that to the Moberg reconstruction from 2005. Once again it is very difficult to see the influence of solar activity on the Earth’s temperature.
While it does show very low activity 500 years ago when temperatures were cold, it also shows relatively low activity 1,000 years ago when temperatures were higher than normal.
So in the modern day high resolution data there is not clear effect of solar activity on the Earth’s temperature. In the long term reconstruction there is also a distinct lack of solar activity causing changes to the Earth’s temperature.
Based on the available data it is impossible to make any useful temperature predictions based on solar activity. To do so is the same exact trap that warmists have fallen into with their conclusion that CO2 levels have caused the recent warming. There is no difference in the two conclusions. Very broad correlations like solar activity and CO2 levels do not prove anything. While Solanki concluded that the solar activity over the past 70 years is “exceptional” the actual temperature of the past 70 years has not been exceptional on the scale of the Holocene.
While I cannot say that there is no influence at all, it is clear that it is not a driving force of the Earth’s temperature and the prediction that low solar activity will reverse warming is unwarranted. The Earth will cool down in the future and it might happen 5 years from now, but it might not happen for another 30 years. Anyone who predicts that the low solar activity will cause cooling risks appearing as foolish as those the predict warming based on CO2 levels.