These data represent part of the high energy GCR spectrum. For comparison the relative sunspot number is plotted, which follows closely the solar 10.7 cm flux. Notice that the amplitudes of the solar activity cycle and the amplitudes of GCR are not closely related, which is fortunate since it gives a possibility to make a distinction between long term trends in the two. As will be shown in the next paragraph, solar activity is not just varying on decadal time scales but also on much longer time scales. The neutron data has been normalized to May 1965, and the ionization chamber data has been normalized to 1965.
Bottom curve is the relative sunspot number.
Note that even though there is a clear solar cycle modulation of the Cosmic ray flux, the amplitudes are not well correlated. Solar Activity and Earth's Climate For more than a hundred years there have been reports of an apparent connection between solar activity and Earth's climate. William Herschel, a famous scientist in London suggested in 1801 that the price of wheat was directly controlled by the number of sunspots, based on his observation that less rain fell when there was few sunspots. Since then numous reports have indicated a link between solar activity and climate, of which most where based on regional observations that in some cases gave conflicting results. Solar activity is now known very long back in time due to the production of isotopes in the atmosphere by galactic cosmic rays.