1) Grand Solar Minimum (GSM) and mini ice age
Besides the paper in 2014 in ApJ where we described the method of quantifying the eigen vectors of solar magnetic field, we published the other paper Zharkova et al, 2015 in Nature Scientific Reports https://www.nature.com/articles/srep15689. We shown that the modern GSM is similar to that which happened in 17 century – Maunder Minimum, and to other GSMs happened before every 350-400 years (Oort minimum, Wolf minimum etc).
The paper was presented at the National Astronomy Meeting in Landudno in July 2015 and featured in the RAS press release https://nam2015.org/press-releases/64-irregular-heartbeat-of-the-sun-driven-by-double-dynamo many other media articles. You can type mini ice age to find the links to them.
In 2020 Zharkova has also published an editorial article in the Atmosphere journal https://www.tandfonline.com/doi/full/10.1080/23328940.2020.1796243 explaining how this cooling will act on the terrestrial atmosphere via reduction of ozone layer, change of magnetic field and jets in the terrestrial atmosphere. V.Zharkova also published much more papers in 2018-2021, which explore different aspects of the upcoming GSM and those which happened in the past. You can find them on my website https://solargsm.com under publications.
Recently we confirmed that the modern GSM has arrived in the paper published in Monthly Notices of the RAS Zharkova and Shepherd, 2022 https://solargsm.com/wp-content/uploads/2022/04/zharkova_shepherd_mnras22.pdf.
This paper used another cycle 24 to the data analysis (21-24 cycles), confirmed our previous finding and explained from the SILSO website site that the current cycle 25 has the largest number of spotless days over all other cycles. The GSM is started in 2020 and taking a strength with every year. But the coolest period is expected in 2030-2040 when solar cycle 26 will be the weakest ever recorded.
Since during Maunder Minimum the Earth was cooling significantly, we expect the similar things will happen during the modern GSM (2020-2053). We hope it will go with the scenario close to that of Maunder Minimum which was described in the paper by Shindel et al, 2001 https://earthobservatory.nasa.gov/images/7122/chilly-temperatures-during-the-maunder-minimum mentioned in the editorial paper of 2020.
2). Global warming and link to GSM
Actually, cooling caused by GSM happens simultaneously with a global warming caused by the fact that in this millennium (1600-2600) the Sun moves closer to the Earth orbit’s position of the spring equinox.
In July 2019 we published another paper in NatSR Zharkova et al, 2019 reporting about two-millennial oscillations of the baseline of solar magnetic field suggesting that these variations are caused by solar inertial motion, or gravitation of large planets on the Sun, shifting the sun from the ellipse focus towards the Earth orbit. This SIM happens over the period of 2100 years (Hallstatt’s cycle), which was also detected in the variations of solar irradiance. This suggestion of terrestrial warming coming from the Sun has scared the AGW people and they demanded to retract our paper that was done by the SR Editor on the 4 march 2020.
Then in March 2021 V. Zharkova has been published the book chapter ‘Millennial oscillations of solar magnetic field and solar irradiance and their effect on the terrestrial atmosphere https://www.intechopen.com/chapters/75534.
This chapter confirms that, contrary to the retraction note, our paper Zharkova et al, 2019 was correct when reporting two-millennial oscillations of solar magnetic field. In the chapter I proved with the ephemeris of the Sun-Earth distances that the Sun-Earth distances are decreasing in in this millennium (1600-2600) that leads to the increase of solar irradiance. I even confirmed that the variations of Sun-Earth distances approach 0.016 au per two millennia that was similar to the distance we estimated in the paper Z2019.
This increase of solar radiation in the current millennium is caused by the Sun’s shift from the ellipse focus towards the spring equinox position off the Earth orbit. This process is called solar inertial motion induced by the gravitation of large planets. Nobody on Earth can do this heating we get, only sun can provide the required energy!
This SIM effect explains the global warming on Earth and other planets we had since 1700.
Again since all the energy to Earth comes from the Sun, when Sun enters the grand solar minimum (GSM), as it happens now, the reduction of solar radiation caused by GSM will override the global warming caused by SIM. The Sun is still at the same distance to Earth in 2020-2053, since SIM operates on millennium scale.
You can read section 5 in the book chapter for a brief explanation how the Grand Solar Minima interacts with the global warming.
But this SIM cannot offset the mini ice age induced by GSM because the Sun is the only source of energy for the Earth and all other planets. When it stops firing sunspots and active regions during the GSM, as it happens right now and for the next 30 years, all the planets will feel the chill, similar to that during Maunder Minimum.
3) Summary
Now we have some undeniable facts about the modern GSM:
1. The Sun reveals since 2020 more spotless days than ever been seen between the cycles or at the start of a cycle during the past 360 years https://www.sidc.be/silso/spotless (see also Fig.1 in our recent MNRAS paper https://solargsm.com/wp-content/uploads/2022/03/zhar_etal_mnras_2col_rev2_v1.pdf.
2. The solar activity cycle 25 is approaching its maximum, so the solar radiation yet is not reduced very much. But the observations show the change of leading magnetic polarities of sunspots that appears much earlier in cycle 25 (normally it should appear at the descending phase of a cycle, not at its ascending phase as happens now in cycle 25.
3. Hence, the real cooling will be noticeable after 2025-2026 towards 2030-2035. This can lead to cold and snow in May-june or even to the absence of summers during some years. Winters may become colder in these years, we will need more heating but it is survivable. More difficult will be a survival of shorter vegetation period for wheats, many fruits, vegetables and food for animals.
4. However, even in the past two years the terrestrial temperature started dropping in many locations if you look at the Electroverse reports : snows and cold even in Arabia, very cold winter in Antarctica, increase of the ice area coverage in both Arctics and Antarctica.
5. We also found that in the next cycle 26 (2031-2042) one can expect strong decrease of solar activity. At the same time it is expected the increase of volcanic eruptions that can lead to the additional cooling because of the ashes in the atmosphere. Therefore the years 2030-2045 will be the most challenging ones in terms of reduction of terrestrial temperature..
You can browse my website https://solargsm.com for more recent publications, news and explanations about solar activity and our recent finding published in 2020-2022.