Speaker
Description
A variation of the solar energy received by the earth – quantified by the Total Solar Irradiance (TSI) – is a radiative forcing for climate changes on earth. Since [Eddy, 1976], solar-climate research has been dominated by the paradigm that solar activity and TSI have been slowly increasing since the Maunder Minimum - extending from about 1645 to 1715 – and the present, which was believed to be a Modern Solar Maximum. If this paradigm were valid, over the last 50 years, when most of the global warming has occurred, this warming would be partly due to anthropogenic greenhouse gas warming, and partly due to natural solar warming.
However, evidence has been accumulating against the ‘Modern Solar Maximum paradigm’. Based on this evidence, [Dewitte et al, 2022] published a new reconstruction of the centennial TSI variation from 1700 to 2020. This new centennial TSI reconstruction is nothing less than a paradigm shift for Sun-Climate research. Following the new TSI reconstruction, the TSI did not gradually increase over the last 320 years, but rather varied with a long term periodicity of 105 years. During the last 105 years, the maximum TSI amplitude occurred in 1957, and the minimum TSI amplitude occurred in 2014. Therefore, since 1957, the sun did not contribute to global warming, but rather tried to cool the earth, partly counteracting greenhouse gas warming. Since the minimum of the 105 year variation occurred in 2014, a trend reversal appears to have taken place and for the next 50 years we can expect that the sun will contribute to global warming, making it more difficult for mankind to reach the goals of the Paris Climate Agreement, in order to avoid catastrophic climate change.
References
[Eddy, 1976] Eddy, J.A., 1976. “The Maunder Minimum: The reign of Louis XIV appears to have been a time of real anomaly in the behavior of the sun.” Science, 192(4245), pp.1189-1202.
[Dewitte et al, 2022] Dewitte, S., Cornelis, J. and Meftah, M., 2022. “Centennial total solar irradiance variation.” Remote Sensing, 14(5), p.1072.
