Nicola Scafetta has a new paper, “Climate change and its causes — a discussion about some key issues” (13MB pdf). One “key issue” is “a large 60 year cycle in the temperature record”
I found the graphic below in Appendix W most interesting.
The bi-secular solar cycle: Is a 2010-2050 little ice age imminent?
Top: The figure shows the sunspot record. Data from Appendix E and V suggest that there exists a large bi-secular solar cycle with period roughly between 160 and 260 years, which corresponds to the Suess frequency band. See the figures and Table 1 in Ogurtsov et al. [2002, Long-period cycles of the suns activity recorded in direct solar data and proxies, Solar Phys. 211, 371-394]. These cycles are responsible for the little Ice Age periods seen in the climate during the last millennium. The latest little ice age on the Earth occurred during the solar Dalton Minimum lasting from about 1790 to 1830.
Bottom: Solar cycles #1, 2, 3 and 4 are compared with the solar cycles #20, 21, 22 and 23. The two sequences are separated by about 210 years. The figure suggest a repeating pattern. There is an increase during the cycles #1, 2 and 3 followed by a decrease in cycle #4 that repeats for the cycles #20, 21, 22 and 23. Also the length of cycle # 4 almost corresponds to the length of cycle #23, which was about 13 years. If the bi-secular solar cycle repeats, a new solar minimum lasting a few decades should be expected. This new low solar activity cycle may induce a further cooling of the climate during the first half of the 21st century.
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