Prediction of Solar Cycles: Implication for the Trend of Global Surface Temperature

Abstract

The findings arising from the investigation of the controversy surrounding the predictions of solar cycles and trends of variation of solar activity with global surface temperature during the currently observed deep decline of solar-geomagnetic activity is reported in this work. Solar activity grand minimum expected to be accompanied by little ice age conditions and global surface temperature rise by ~4.8 ^oC as at 2100 have been proposed. The prediction of the rise in global surface temperature was based on the monotonic rise in anthropogenic greenhouse emissions, which was also predicted to occur within the same time frame. There is the need to specify whether or not solar-geomagnetic activity variability determines the trend of variation of global surface temperature. Consequently, low-pass filter functions were used to establish the trends of solar-geomagnetic activity and global surface temperature phenomena. The trends were subjected to auto-correlation and regression analyses which formed the basis of extrapolation and prediction. Results obtained reveal that the recent solar activity Modern Maximum was a recovery from the Maunder Minimum and that the character of the next grand episode may likely be a minimum. It was also found that the expected grand minimum will most likely give rise to low global surface temperature with the coldest phase in 2046±11 and that it will be ~0.1°C above the current baseline in 2100 as opposed to 4.8°C predicted by general circulation models (GCM). Significant evidence indicated that the long-term trend of global surface temperature variation is characterized by low-frequency cycles (in the Gleissberg period range or longer) which are most likely related to those of the activity of solar-geomagnetic phenomena with strong conformity to solar activity period change rules. The long-term high solar-geomagnetic activity trend which was observed to persist up to 2003 was the most likely cause of the continued rise of global surface temperature until the decrease in the rate of climate warming since the early 2000s. The results and findings from the present study led to the conclusion that the recent climate scenarios were predominated by the direct solar irradiance climate forcing and indirect amplification processes associated with solar and geomagnetic activity variability.