“A SCIENTIFIC PEDIGREE”
by Viv Forbes, Executive Director, The Saltbush Club, ©2018
The first connection between solar activity and climate was made by the Greek astronomer Meton in the 5th century BC. Meton had noticed a correlation between higher sunspot activity and higher rainfall. The correlation was rediscovered in the 19th century by William Jevons who compared solar data with historic wheat prices. The correlation between solar activity and the wheat market in medieval Europe was confirmed by two Israeli researchers in 2004. The most recent affirmation is Nir Shaviv’s testimony to the German Parliament in November 2018. Exhibit one is his graph of the rate of change of sea level with the change in the solar constant:
Figure 1: Quantifying the solar forcing
The control of climate by solar activity has a scientific pedigree going back over two and half thousand years. From here it is just a case of explaining mechanisms, backtesting relationships and making predictions of solar activity levels.
One of the bigger mechanisms, elucidated by the Danish researcher Henrik Svensmark, is the stronger solar wind during high solar activity pushing galactic cosmic rays away from the inner planets of the solar system. That means fewer neutrons reaching the lower troposphere and thus fewer nucleation sites for cloud droplets. In turn less cloud means more solar radiation reaches the Earth’s surface instead of being reflected back into space.
One of the best bits of evidence for Svensmark’s theory is the 10Be from Antarctic ice cores:
Figure 2: Dye 3 Be10 record 1424 to 1985
The upward spikes correlate with the cold periods over the last 600 years. The spike at the Maunder Minimum was particularly brutal, killing off 30% of the populations of some of the Baltic states. As with a lot of natural systems, the reality is a lot more complex. For example this article explains the contribution of length of day (LOD) and notes a four year lag from changes in LOD to changes in sea surface temperature.
As the low 10Be figures for the second half of the 20th century in Figure 2 attest, the mild warming of the planet that got some people hot and bothered was due to higher solar activity. That period of higher solar activity ended in 2005 as shown by a sharp break in some solar activity parameters. One of the best of these is the aa Index which has been measured since 1868:
Read the rest here.