Be-10, Sunspots, and Climate Change

 What causes climate change?  The climate change crowd claim that they have accounted for changes in solar output.  The problem is that they are looking only at primary effects.  Changes in solar output appear to affect interstellar origin cosmic ray flux.  The abstract from Harvard:

Time Variations of 10BE and Solar Activity

It is demonstrated that Be-10 is a useful tool to reconstruct the history of solar activity. A comparison of neutron flux at the earth's surface with the number of sunspots exhibits a clear negative correlation which is due to solar wind interaction with the Galactic cosmic-ray flux. Since cosmogenic Be-10 production is proportional to the n-flux in the atmosphere, it also shows the inverse correlation with solar activity. Other sources of Be-10 variations in geologic reservoirs are changes of the geomagnetic dipole field and transport, and deposition processes within the atmosphere. Polar ice cores record the atmospheric fallout over the last ca 100,000 yr. Detailed Be-10 studies in these cores reveal the expected negative correlation and phase lag with sunspots. Periods of low solar activity, such as the Maunder minimum, are clearly reflected by higher Be-10 concentrations. In order to reduce the climatic signal introduced by atmospheric transport, Be-10 records from Greenland and Antarctica were combined and compared with C-14 tree-ring data. The generally good agreement of these comparisons strongly indicates that the main source of the short-term Be-10 variations is solar modulation of the cosmic rays and that several Maunder-minimum-type periods occurred during the last few millenia.

 Originally published in Space Science Reviews (2000):

 Thus, a moderate influence on atmospheric aerosol distributions from cosmic ray ionisation would have a strong influence on the Earth’s radiation budget. Historical evidence over the past 1000 years indicates that changes in climate have occurred in accord with variability in cosmic ray intensities. Such changes are in agreement with the sign of cloud radiative forcing associated with cosmic ray variability as estimated from satellite observations.

Lower solar output -> more cosmic ray input -> changes in Earth's climate.  Amazing how you never hear the alternative theory, isn't it?