Comment on the paper “Characteristic time scales of decadal to
centennial changes in global surface temperatures over the past 150
years ” by J.L. Le Mouël, F. Lopes and V. Courtillot First published:
14 October 2019 in Earth and Space Science
Abstract
In their paper, Le mouël et al, (2019) argued that over the past 150
years “most of the variability of surface temperatures could be natural
and primarily controlled by the Sun”. We do not agree with their
conclusions for several reasons which are (1) a biased interpretation of
the Fourier and SSA spectrum, which show no significant co-variability
between sunspot amounts and emperature, (2) the small radiative forcing
associated with the long-term sunspot variability, and finally the
evidence that the slowly-varying components of the temperature and
sunspots time-series show opposite trend in the last 30 years.