Climate change

Conclusions

In this editorial, I have demonstrated that the recent progress with understanding a role of the solar background magnetic field in defining solar activity and with quantifying the observed magnitudes of magnetic field at different times allowed us to enable reliable long-term prediction of solar activity on a millennium timescale. This approach revealed a presence of not only 11-year solar cycles but also of grand solar cycles with duration of 350–400 years. We demonstrated that these grand cycles are formed by the interferences of two magnetic waves with close but not equal frequencies produced by the double solar dynamo action at different depths of the solar interior. These grand cycles are always separated by grand solar minima of Maunder minimum type, which regularly occurred in the past forming well-known Maunder, Wolf, Oort, Homeric, and other grand minima.

During these grand solar minima, there is a significant reduction of solar magnetic field and solar irradiance, which impose the reduction of terrestrial temperatures derived for these periods from the analysis of terrestrial biomass during the past 12,000 or more years. The most recent grand solar minimum occurred during Maunder Minimum (1645–1710), which led to reduction of solar irradiance by 0.22% from the modern one and a decrease of the average terrestrial temperature by 1.0–1.5°C.

This discovery of double dynamo action in the Sun brought us a timely warning about the upcoming grand solar minimum 1, when solar magnetic field and its magnetic activity will be reduced by 70%. 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.