Die kalte Sonne website presents an article on a potential approaching solar grand minimum.
by Frank Bosse
Solar activity has also been very modest this month. One has been able to observe only 48% of the mean value of the activity of the previous cycles for the current cycle, the sunspot number was only 52,5. Here’s how it looks graphically:
Sunspot number (SSN) versus months after the start of the cycle.
With respect to the previous month, with 78.7 it is a significant decrease. This is clear when compared to Cycle No. 5, which here has long been used as a reference for a weak 11 year Schwabe cycle. In the middle curve it is plain to see that statistically, the maximum is already passed. And in the case of the current SC24? An anyswer may be provided by the polar magnetic field of the sun, the poles reverse at the maximum:
The difference between the field strength of the northern and southern polar fields has clearly reversed signs, meaning the SC24’s maximum is most likely history. It had already occurred in November 1997 with a SSN of 96.7 . The comparison of the summed sunspot anomaly taking into account the the discontinuity of the counting method about 1945 shows that the current SC 24 is the weakest in almost 200 years:
In our monthly series in consideration of solar activity, a number of authors have been brought up who think it’s probable that the sun is headed for a grand minimum similar to the Maunder- Minimums of 1649-1715. That may already manifest itself in 2020. There have already been studies that attempt to project the impacts on global temperatures. Included here is a study from Meehl et al. 2013. As an input the authors look at an approximately 0.25% reduction in Total Solar Irradiance (TSI) between 2020 and 2070:
Source: Meehl et al. 2013
They fed this into a climate model. Result: global temperatures could drop around 0,2…0,3 degrees Celsius with local peak values of up to 0.8°C, especially in the middle and upper latitudes of the northern hemispheres:
Source: Figure 3c of Meehl et al. 2013.
The model used by Meehl et al. employs a high climate sensitivity with respect to greenhouse gases, foremost CO2, and it is thus little wonder that the shown cooling with respect to the warming on top of it in the simulation only has a temporary effect and a moderate braking effect. The questions that a critical observer may ask are the following:
- Is the magnitude of sensitivity with regards to GHG in the model really assured when we consider the current stagnation of global temperatures since at least 2001 – while CO2 has steadily increased?
- Is the TSI in the paper, viewed as the “motor”, solely what one could expect to act or does spectral variation (especially UV) make an additional contribution? The same needs to be asked about the significantly increasing galactic cosmic radiation.
We see: Forecasts are very difficult – especially when they concern the future.”