Is Ice Age coming ? Solar Cycle 25


October 9, 2021


2020 marked the beginning of the 25th solar cycle. Scientists say the Sun may be going through a long period of decreased activity known as the Modern Grand Solar Minimum from 2020 to 2053. The last time such an event occurred was during the Maunder Minimum — from 1645 AD to 1710 AD, which was part of what is now known as the Little Ice Age. Should we prepare for another Ice Age ?


Fortunately we had global warming. National Aeronautics and Space Administration (NASA) in February 2020, released a statement that dispelled the fact that there would be any major effect on global temperature rise due to greenhouse gas emissions due to human activities. NASA also said the impact of global warming would be six times greater than the cooling caused by the Grand Solar Minimum.

Solar Cycle 

The Sun has its ups and downs and cycles between them regularly. Roughly every 11 years, at the height of this cycle, the Sun’s magnetic poles flip — on Earth, that’d be like if the North and South Poles swapped places every decade — and the Sun transitions from sluggish to active and stormy. At its quietest, the Sun is at solar minimum; during solar maximum, the Sun blazes with bright flares and solar eruptions.

Researchers at NASA and around the world work on solar activity models and make these forecasts. How reliable are these models and forecasts ? Modeling the Sun is a tricky business because scientists don’t fully understand the internal churning that causes this magnetic flip-flop.

What about Solar 25 ?

Scientists interpret that Solar Cycle 25 will play out in similar fashion to Cycle 24. Solar Cycle 24 was a feeble cycle, peaking at 114 sunspots (the average is 179). Solar Cycle 25 is now underway and expected to peak with 115 sunspots in July 2025. Solar minimum occurred in December 2019.

Global Warming

“The amount of solar energy Earth receives has followed the Sun’s natural 11-year cycle of small ups and downs with no net increase since the 1950s. Over the same period, global temperature has risen markedly. It is therefore extremely unlikely that the Sun has caused the observed global temperature warming trend over the past half-century.” – NASA

Solar Minimum

What do Valentina Zharkova say ?

This period has started in the Sun in 2020 and will last until 2053. During this modern grand minimum, one would expect to see a reduction of the average terrestrial temperature by up to 1.0°C, especially, during the periods of solar minima between the cycles 25–26 and 26–27, e.g. in the decade 2031–2043.

The reduction of a terrestrial temperature during the next 30 years can have important implications for different parts of the planet on growing vegetation, agriculture, food supplies, and heating needs in both Northern and Southern hemispheres. This global cooling during the upcoming grand solar minimum 1 (2020–2053) can offset for three decades any signs of global warming and would require inter-government efforts to tackle problems with heat and food supplies for the whole population of the Earth.

So the scientists are not unanimous about the temperature rise. However one thing is clear. Solar Irradiance is falling.

Going Forward:

Word of Caution for those who install Solar Power

As Solar irradiance is falling, or will fall during Solar 25, you should keep that in mind while modelling.

The output voltage, current and power of PV system vary as the functions of solar irradiation.

The performance of PV systems is highly affected by internal and external factors such as the structural features, aging, radiation, shading, temperature, wind, pollution and cleanliness. Dust is increasing in the environment.

Hussain, A., Batra, A. & Pachauri, R. concluded that a uniform layer of 10 g accumulated on solar PV module can reduce its power up to 25% and when module is accumulated uniformly with 50 g of dust then power is reduced approximately 55–63%.

Abdoulatif Bonkaney, Saïdou Madougou, Rabani Adamou concluded that the effect of cloud cover is immediate with a drop in global solar irradiance and hence in power output for a short time, while the effect of dust accumulation has a long-term effect.

Solcast provides Solar Data and Forecasts. I am not sure if they give 25 year forecast, the time period for which solar developers calculate their returns.

In India too researchers are studying impact of cloud, dust etc on solar power. One of the research paper I found “Solar Energy Estimations in India Using Remote Sensing Technologies and Validation with Sun Photometers in Urban Areas”

So developers and researchers should collaborate while calculating Solar power output and study the impact of Solar 25 on Solar Power.

Ice age or not, we do not want a power crisis, because electricity can provide cooling as well as heating. But if not electricity, then we are doomed.


4. Zharkova, Valentina. “Modern Grand Solar Minimum will lead to terrestrial cooling.” Temperature (Austin, Tex.) vol. 7,3 217-222. 4 Aug. 2020, doi:10.1080/23328940.2020.1796243

5. Hussain, A., Batra, A. & Pachauri, R. An experimental study on effect of dust on power loss in solar photovoltaic module. Renewables 4, 9 (2017).


7. Abdoulatif Bonkaney, Saïdou Madougou, Rabani Adamou, “Impacts of Cloud Cover and Dust on the Performance of Photovoltaic Module in Niamey“, Journal of Renewable Energy, vol. 2017, Article ID 9107502, 8 pages, 2017.



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