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22-Year magnetic solar cycle [Hale cycle] responsible for significant underestimation of the Sun’s role in global warming but ignored in climate science
  • Martijn van Mensvoort
Martijn van Mensvoort
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Corresponding Author:martijn.van.mensvoort@gmail.com

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Reconstructions for global temperature development show an upward oscillation for the period of the 1880s through 1980s. This oscillation is being associated with natural variability and the temperature rise between the 1910s and 1940s with increased solar activity. The temperature impact of the 11-year solar cycle [Schwabe cycle] and the physical mechanism involved are insufficiently understood. Here, for the 22-year magnetic solar cycle [Hale cycle] a seawater surface temperature [SST] impact is described of 0,215 °C (0,238 ± 0,05 °C per W/m2); the derived impact for the 11-year cycle is 0,122 °C (0,135 ± 0,03 °C per W/m2). Also, a parallel development is described for seawater surface temperature [HadSST3 dataset] and the minima of total solar irradiance [LISIRD dataset] after a correction based on the 22-year solar cycle polarity change. With the correction, the combination of the positive and negative minima shows for the period 1890-1985 a high SST solar sensitivity: 1,143 ± 0,23 °C per W/m2 (with 90,5% declared variance). This implies that the Sun has caused a warming of 1,07 °C between Maunder minimum (late 17th century) and the most recent solar minimum year 2017 - which is well over half of the intermediate temperature rise of approximately 1,5 °C. The results demonstrate that the 22-year cycle forms a crucial factor required for better understanding the Sun-temperature relation. Ignoring the 22-year cycle leads to significant underestimation of the Sun’s influence in climate change combined with an overestimation of the impact of anthropogenic factors and greenhouse gases such as CO2.