So why sunspots? The increase or decrease, in the number of sunspots, signifies changes in the Sun’s electromagnetic activities and numerous studies have demonstrated that solar activity is important factor in climate variability.
Planet Earth derives virtually all its energy from the Sun, in the form of solar radiation, in different wavelengths. We get light and heat from the sun for example. We also know that the Sun has its own 11 year cycle, amongst others, and this can be directly correlated to sunspot numbers.
So, what does this mean ? What has been discovered is that the amount of energy received from the Sun varies with sunspot numbers within this 11 year cycle. It would appear that when there are reduced numbers of hotspots the Sun is actually putting out less energy. The other important factor is that the Sun’s electromagnetic field protects Earth from cosmic radiation. The number of sunspots is believed to be, directly, related to the strength or weakness of electromagnetic activity. It follows therefore, that when the Sun has a weakened electromagnetic field and consequently less sunspots not only does the Earth receive less energy but is more susceptible to cosmic bombardment.
The science here is quite complex and for deeper reading I would recommend the following articles :
- Zharkova, Valentina. ‘Modern Grand Solar Minimum Will Lead to Terrestrial Cooling’. Temperature, 4 August 2020, 1–6. https://doi.org/10.1080/23328940.2020.1796243.
2. Svensmark, Henrik, and Global Warming Policy Foundation. Force Majeure: The Sun’s Role in Climate Change, 2019. © Copyright 2019 The Global Warming Policy Foundation.
The chart below correlates sunspot observations since 1600AD and then forecasts what, is believed, could be happening now. We know from records that a much cooler climate prevailed during the 1600’s (Maunder minimum) and pictures exist of markets being held on a frozen river Thames in London.
We also know, from observations that sunspots have been minimal or non-existent during recent times. The chart goes on to predict what might be happening now, illustrating that we are entering a cooling period equivilent to the ‘Maunder minimum’ the so called ‘mini ice age’ of the 1600’s.
This next chart illustrates how sunspots correlate to cosmic radiation. Clearly shows that when sunspots diminish that cosmic radiation received climbs. Why this is relevant will be explained below.
From 1645 to 1710 temperatures across the Northern Hemisphere dropped correlating with a quieter Sun which is referred to as the ‘Maunder minimum’ or ‘mini ice-age’. It is suggested that it only took a drop in total solar irradiance of 0.22% to cause frozen rivers, cold long winters and cold summers in the Northern hemisphere.
This change in solar irradiance and susequent temperature drop is also amplified by the reduction in the strength of the solar magnetic field. The upshot is that the Earth becomes subject to greater cosmic particle intensity. Again, I wont try and explain the science here, but the increase in cosmic particles leads to the formation of high clouds. Clouds reflect some of the incoming solar energy increasing the cooling effect.
Potentially, this cosmic bombardment also interacts with Silica rich magmas making the liklihood of earthquakes and volcanoes more active. If more volcanoes are throwing particles into the atmosphere then a further cooling effect takes place.
Professor Zharkova predicts that we will be experiencing a modern grand solar minimum between 2020-2053 and again between 2370-2415. A cooling period is then to be expected. We cant be sure how, exactly, this will affect the Earth but watch this space for further updates.
Copyright M. Taylor 2020
The Inevitable Climate Change 