A new paper in Astronomy and Astrophysics (A&A) finds that cosmogenic nucleides in a section of Epica dome C covering 325-336 kyrs ago doesn’t exhibit Abreu et al’s planetary periods. They conclude that solar variability might have been different then. They don’t consider that Epica ice cores might not be telling them what they think they’re telling them.
Here’s the abstract
No evidence for planetary influence on solar activity 330 000 years ago
A. Cauquoin1⋆, G. M. Raisbeck2, J. Jouzel1, E. Bard3 and ASTER Team3⋆⋆
Context. Abreu et al. (2012, A&A. 548, A88) have recently compared the periodicities in a 14C – 10Be proxy record of solar variability during the Holocene and found a strong similarity with the periodicities predicted on the basis of a model of the time-dependent torque exerted by the planets on the sun’s tachocline. If verified, this effect would represent a dramatic advance not only in the basic understanding of the Sun’s variable activity, but also in the potential influence of this variability on the Earth’s climate. Cameron and Schussler (2013, A&A. 557, A83) have seriously criticized the statistical treatment used by Abreu et al. to test the significance of the coincidences between the periodicities of their model with the Holocene proxy record.