Periodicities in mean sea-level fluctuations and climate change proxies

Jennifer Marohasy has a new post “Revisionist Approach Destroys Information About Natural Cycles Embedded in Climate Data” where there is underlying interest for Talkshop readers. Mention of Ken Ring is perhaps not so good given a reputation for excessive claims, caveat emptor.

Her take is from an Australian perspective mentioning a Senator and the lead author is Australian.

Periodicities in mean sea-level fluctuations and climate change proxies: Lessons from the modelling for coastal management
R.G.V. Baker, , S.A. McGowan
BCSS, Faculty of Arts and Sciences, University of New England, Armidale, NSW 2351, Australia
Available online 12 July 2014

Elsevier so it is paywalled http://dx.doi.org/10.1016/j.ocecoaman.2014.05.027

Abstract

The question of whether sea levels and global temperatures are accelerating or decelerating is a major source of current debate. Single taper and multi-taper spectral analysis from seventeen globally distributed tidal stations and twenty climate proxies show aggregate significant common periodicities in mean sea level fluctuations and the climate proxies of approximately 7 yr, 13 yr, 23 yr, 32 yr, 41 yr, 53 yr, 66 yr, 88 yr, 105 yr and 132 yr, respectively. These periods are shown to strongly correlate with an harmonic sequence of n, m = n + n/4 and p = n + n/2n for n = 5.5 yr and this synchronicity allows for a climate state function to be defined by Lotka–Volterra limit cycles. Such a model can include both anthropogenic warming and complex natural cycles, based on past evidence, and these cycles can form or bifurcate into extreme events close to critical values. The model suggests that accelerating sea levels can be in-phase, but lag decelerating global temperatures or vice versa, so a ‘pause’ in global warming should not be surprising. Further, the model can simulate the uneven regional effect of climate responses and replicate the chaos apparent in monthly sea-level records. The approach poses ‘a planner’s dilemma’ whereby the likelihood of a present 1 in 100 yr positive extreme event can either be caused by anthropogenic warming within shorter cycles or by a stationary mean in a longer cycle. We simply show that for rising average temperatures in a double period cascading model, there would be a three-fold increase in the likelihood of an equivalent 1 in 100 yr positive extreme event relative to present over a 20 yr period. A consequence to the ‘planner’s dilemma’ is the ‘manager’s risk imperative’ where risk cycles can be quantified into strategic GIS maps of potential future inundations: identifying vulnerability, defining possible economic impacts and underpinning response strategies that are legally defensible and transparent to a range of stakeholders.

Article in The Australian cited by JM
Solar cycles linked to climate pause, assist in coastal planning

JM article Revisionist Approach Destroys Information About Natural Cycles Embedded in Climate Data

I haven’t read the paper. As I think readers will know I (Tim) tend to relatively cool on tight cyclic periods in climatic data but some periodic tendencies are plain. Reasonably there is chaos which can also show a periodic nature including modal change. This might be how the sun behaves.

Patterns and humans, always looking.

Post by Tim