Apart from the obligatory nod to AGW in the final sentence of this abstract, this paper looks like a promising roundup of the natural factors involved in the ~60yr climate cycle, with the notable exception of geomagnetic considerations.
Evidence for two abrupt warming events of SST in the last century
Costas A. Varotsos, Christian L. E. Franzke, Maria N. Efstathiou, Andrei G. Degermendzhi
Theoretical and Applied ClimatologyJune 2013
We have recently suggested that the warming in the sea surface temperature (SST) since 1900, did not occur smoothly and slowly, but with two rapid shifts in 1925/1926 and 1987/1988, which are more obvious over the tropics and the northern midlatitudes. Apart from these shifts, most of the remaining SST variability can be explained by the El Niño Southern Oscillation and the Pacific Decadal Oscillation (PDO). Here, we provide evidence that the timing of these two SST shifts (around 60 years) corresponds well to the quasi-periodicity of many natural cycles, like that of the PDO, the global and Northern Hemisphere annual mean temperature, the Atlantic Multi-decadal Oscillation, the Inter-Tropical Convergence Zone, the Southwest US Drought data, the length of day, the air surface temperature, the Atlantic meridional overturning circulation and the change in the location of the centre of mass of the solar system.
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