Climate Oscillations
Climate Oscillations 12: The Causes & Significance
15 hours ago Andy May 22 Comments
By Andy May
In this post we will examine the idea that ocean and atmospheric oscillations are random internal variability, except for volcanic eruptions and human emissions, at climatic time scales. This is a claim made by the IPCC when they renamed the Atlantic Multidecadal Oscillation (AMO) to the Atlantic Multidecadal Variability (AMV) and the PDO to PDV, and so on. AR6 (IPCC, 2021) explicitly states that the AMO (or AMV) and PDO (or PDV) are “unpredictable on time scales longer than a few years” (IPCC, 2021, p. 197). Their main reason for stating this and concluding that these oscillations are not influenced by external “forcings,” other than a small influence from humans and volcanic eruptions, is that they cannot model these oscillations, with the possible exceptions of the NAM and SAM (IPCC, 2021, pp. 113-115). This is, of course, a circular argument since the IPCC models have never been validated by predicting future climate accurately, and they also make some fundamental assumptions that simply aren’t true.
They also state that the variance over the observational records in the Pacific and Atlantic exhibit no significant changes (IPCC, 2021, p. 114). This is disputed in the peer-reviewed literature (Ghil, et al., 2002), (Scafetta, 2010), (Mantua, et al., 1997), and (Gray, et al., 2004). All the listed sources, and many others, found the AMO, PDO, ENSO, or the global mean surface temperature (GMST) oscillations to be statistically significant at the 95% level or higher, usually by comparing them to red or white noise.
While AR6 WGI (page 196) believes that the statistical significance of a change in climate (a signal to noise ratio greater than one) can be estimated with either observations or models, I believe only observations should be used. For the purposes of this post, a trend in observations will be tested versus a mean state with no definable time period, like white noise. That is, it covers all frequencies equally. We will also refer to “red noise,” which is like white noise, but has a higher content of lower frequencies and provides a stricter test than white noise (Ghil, et al., 2002).
https://wattsupwiththat.com/2025/08/05/climate-oscillations-12-the-causes-significance/
