Seldom has the sun been as strong as we have seen it over the last 5 decades. Is it just a coincidence that the largest warming of the last 500 years occurred during this phase? What climatic consequences could the decline in solar activity have in coming decades?
Just a few years ago the tide changed when the sun ended its hyperactive phase. Few people had anticipated this, and so it was a surprise for many. Solar physicist Leif Svalgaard of California’s Stanford University expressed it as follows at the American Geophysical Union last December:
“None of us alive have ever seen such a weak cycle. So we will learn something.”
And so science commenced to consider and think about what all this could lead to. The latest works on the subject include Qian et al. 2014 (“Secular changes in the thermosphere and ionosphere between two quiet Sun periods“), Zhao et al. 2014 (Modulation of galactic cosmic rays during the unusual solar minimum between cycles 23 and 24) and McCracken & Beer 2014 (Comparison of the extended solar minimum of 2006–2009 with the Spoerer, Maunder, and Dalton Grand Minima in solar activity in the past).
After a number of studies it has become clearer: It’s only the beginning! It is expected that the sun will continue becoming quieter over the coming decades. This has pretty much become the consensus among solar physicists. The latest studies on the subject come from Roth & Joos 2013, who assume a decline in solar activity to normal levels will occur during the 21st century. Salvador 2013 goes further and anticipates a solar minimum for the coming 30-100 years. Read the original abstract:
Using many features of Ian Wilson’s Tidal Torque theory, a mathematical model of the sunspot cycle has been created that reproduces changing sunspot cycle lengths and has an 85% correlation with the sunspot numbers from 1749 to 2013. The model makes a reasonable representation of the sunspot cycle for the past 1000 yr, placing all the solar minimums in their right time periods. More importantly, I believe the model can be used to forecast future solar cycles quantitatively for 30 yr and directionally for 100 yr. The forecast is for a solar minimum and quiet Sun for the next 30 to 100 yr. The model is a slowly changing chaotic system with patterns that are never repeated in exactly the same way. Inferences as to the causes of the sunspot cycle patterns can be made by looking at the model’s terms and relating them to aspects of the Tidal Torque theory and, possibly, Jovian magnetic field interactions.
In the Journal of Geophysical Research a study by Goelzer et al. appeared in December 2013 and also foresees a decline in solar activity.
What climatic consequences could this have? In our book “The Neglected Sun” we assume that temperatures could be two tenths of a degree lower by 2030 as a result, which would mean warming getting postponed far into the future.