Radiation from the sun was considered constant since. In the 1890s, astronomer E. W. Maunder reported that solar activity was greatly reduced in the years 1645 to 1715. There was a direct correlation between the minimum solar activity and the coldest climate period recorded in Europe. In the 1970s, ice core samples from Greenland began to be studied. They revealed that radiation from the sun has large variations over thousands of years.
Periods of deep minimum radiation from the sun were named after the solar scientists: Oort (1010-1070), Wolf (1270-1340), Spörer (1390-1550), Maunder (1640-1720) and Dalton (1790-1820). Deep minimum radiation could explain the Little Ice Age. The deep minima led to the discussion of a possible new Maunder radiation minimum, and a new cold climate period.
Planets and sun’s radiation
NASA started satellite-based monitoring radiation from the sun in 1979. In 2014, scientists from NASA were able to publish a continuous radiation timeseries for the years 1700-2013. An examination of the timeseries revealed the signature (periods and phase) from the planets Jupiter (12 years), Saturn (29 years), Uranus (84 years) and Neptune (164 years) (JSUN). The same signature was identified in the Sun’s rotation around the barycenter of the Solar System. There is a direct correlation between the elliptical planet orbits, the Sun rotation around the barycenter, and total radiation from the Sun [1].
The explanation is that the elliptical orbits of the planets change the speed of the Sun’s rotation around the solar system barycenter. Changes in the Sun’s rotation speed affect the Sun’s internal dynamo and radiation from the Sun’s surface. The sun has minimum radiation when the planes have maximum speed closest to the sun (perihelium). The radiation has Deep minimum when the UN planets (Uranus and Neptune) are closest to the Sun at the same time, Grand minimum when the SUN planets (Saturn, Uranus and Neptune) are closest to the Sun, and Fimbulwinter minimum when the JSUN planets are closest to the Sun. The sum of JSUN periods is then a TSI index, which represents the maximum or minimum radiation from the sun [2].
Deep minimum 520-570AD
Figure 1. Computed SUN orbit index (Saturn (blue), Uranus (green), Neptune (gray) and TSI-index (red) (Saturn + Uranus + Neptune) for the years 500-600 e.Kr.
Figure 1 shows how the sun distances index of the SUN planets for the years 500-600 e.Kr. TSI index (red) shows that radiation from the Sun has a deep minimum in the years 520-570. A deep minimum in the years 520-570 leads to an estimated global cooling up to the year 570. Global climate is directly related to sea surface temperature [2].
Deduced radiation (TSI-index < 0) leads to an estimated cold climate period in the years 530-665. Swedish researchers have mapped that Northern Europe had a deep cold climate period in the years 520-660. This cold climate period caused a large migration in northern Europe. Half of the population in Norway and Sweden disappeared, and large areas became deserted farms. Correspondence between JSUN periods repeats itself in periods of 500 years.
Fimbulwinter
Fimbulwinter is referred to in the saga as an extremely cold climate period with a duration of 3 years. A period of three years without a summer. This myth has been associated with a real event caused by volcanic eruption that led to a global weakening of radiation from the sun. Recent research shows that global temperature fell by about 1 degree in the years 535-536 e.Kr. In Honduras, there was a major volcanic eruption around the year 540. The odd thing is, that the timing coincides with a JSUN TSI-index minimum. The JSUN planets have a Fimbulwinter minimum (TSI-index = -3.25) in the year 534 e.Kr.
Grand minimum 1675-1745AD
Figure 2. Computed SUN orbit index (Saturn (blue), Uranus (green), Neptune (gray) and TSI-index (red) for the years 1675-1745 e.Kr.
The Maunder minimum period (1640-1720) is considered the coldest climate period in more than 4000 years. Figure 2 shows that the SUN TSI index is negative in the years 1675-1745. JSUN periods created a perfect Fimbulwinter TSI-index = -4.0 in the year 1709. The year 1709 is known as “The Deep freeze”, the coldest year on record in Europe. In France, the temperature dropped to -20 degrees Celsius. Rivers, canal networks and ports froze. The population of France fell by 600,000 from the year 1709 to 1710. The Baltic Sea was frozen for four months, and it was possible to travel by horse and sleigh across the sea from Denmark to Sweden. Arctic ice surrounded Iceland and moved south to Finmark. In Norway and Sweden, large parts of the population disappeared.
Reduced solar activity from 1675 to 1745 led to global cooling up to the year 1745. Inertia in ocean warming led to a calculated deep cold climate period in the years 1710-1760, with a Grand temperature minimum in the year 1745. The year 1745 coincides with the maximum extent of the Jostedal-glacier in Norway. The Greenland temperature in 1745 was the lowest in 4000 years [2].
Deep minimum 2025-2075AD
The Dalton period (1790-1820) is associated with the end of the Little Ice Age. The TSI-index was still negative in the period 1850-1900. This negative state explains a colder climate period in the years 1885-1930. From 1900, the TSI-index increases in a positive direction to a maximum by the year 2017. This coincides with global warming in the years 1930-2017. The TSI-index peaked in 1917 and is moving in a negative direction until the year 2025. At the same time, a positive TSI-index can explain that global temperature has been virtually constant in the period 2017-2024. This index state indicates that global cooling started around the year 2017.
Figure 3. Planetary periods for Saturn (blue), Uranus (green), Neptune (gray) and TSI index (red) for the years 2000-2100 e.Kr.
The TSI-index reveals a Deep radiation minimum period 2025-2072. The Deep minimum is a 500-year evert, in coincides with (520-570) Deep minimum, Oort (1010-1070) and Spörer (1390-1550) Deep minimum. Inertia in cooling leads to a projected deep cold climate period in the years 2050-2100, with a Grand minimum temperature in the year 2072 [2]. From 2072 a TSI-index > 0. This positive will start of the next global warming period.
Winter is coming
Global climate is characterized by interference between solar-driven accumulation of heat in oceans and lunar-driven heat distribution in oceans [2]. Lunar-driven signature is rooted in the Earth’s rotation and global ocean currents. Interference between solar-driven and lunar-driven warming is poor understood. Both signatures have maximum sea temperatures at the year 2000. This means that solar-driven and lunar-driven climate have coinciding directions towards a new cold climate period.
References
- Yndestad, H., & Solheim, J. (2017). The influence of solar system oscillation on the variability of the total solar irradiance. New Astronomy, 51, 135–152. doi.org/10.1016/j.newast.2016.08.020.
https://ntnuopen.ntnu.no/ntnu-xmlui/handle/11250/2473902 - Yndestad H. 2022. Jovian Planets and Lunar Nodal Cycles in the Earth’s Climate Variability Frontiers in Astronomy and Space Sciences. May 10. 2022. https://doi.org/10.3389/fspas.2022.839794.
- The Climate Clock: https://www.climateclock.no