In this work, we use two decadal sunspot number series reconstructed from
cosmogenic radionuclide data (14C in tree trunks, SN-14C and 10Be in polar ice,
SN-10Be) and the Extreme Value Theory to study variability of solar activity
during the last 9 millennia. The peaks-over-threshold technique was used to
compute, in particular, the shape parameter of the generalized Pareto
distribution for different thresholds. Its negative value implies an upper
bound of the extreme SN-10Be and SN-14C time series. The return level for 1000
and 10000 years were estimated leading to values lower than the maximum
observed values, expected for the 1000-year, but not for the 10000-year return
levels, for both series. A comparison of these results with those obtained
using the observed sunspot numbers from telescopic observations during the last
four centuries suggest that the main characteristics of solar activity have
already been recorded in the telescopic period (from 1610 to nowadays) which
covers the full range of solar variability from a Grand minimum to a Grand
maximum.Comment: 15 pages, 5 figures, 5 tables, accepted for publication in Ap
