The predictability of solar variability. Although there are different long-term “predictions” of solar activity, they are not predictions in a strict sense. It is more correct to call them “possible scenarios”. Such scenarios are based typically on multiharmonic (or neural network or other) mathematical extrapolations of the existing series. This would work if the time series were stationary (in the sense that a sufficiently long subset of data contains the main statistical features of the entire series). However, the solar activity data sets have been shown to be essentially non-stationary thus making true predictions hardly possible because of an essential stochastic/chaotic component. E.g. with an equal success one can predict the behaviour of the financial market and become rich. The issue is that no one knows when the new Grand Minimum occurs and no one really knows what would happen then. I call such extended minima of suppressed solar activity Grand Minima, since the Maunder Minimum (lasting from 1645 till about 1700 or 1712) is only one of those. Later minima, such as the Dalton Minimum (ca. 1800 AD) and modern (ca. 1900 AD) ones were not really Grand Minima, in neither depth or duration
Indeed, we are certain that there will be a Grand Minimum sooner or later (there were 27 ones during the last 11 millennia, see Fig. 2) but their occurrence is unpredictable. The 27 minima during 11 millennia imply that Grand Minima appear roughly every 400 years, but they are spread very unevenly, with intervals between them being from a hundred years to a few thousand years. No regularity was found in their occurrence (except for the ~200-yr repetition appearing sporadically), but rigorous statistical studies suggest that they occur randomly. Thus, no definite prediction of a future Grand Minimum is possible, but a probabilistic forecast can be made, e.g. Barnard et al., (2011) said: “There is an 8% chance of the Sun falling into a grand minimum during the next 40 years”. This is not a prediction but a probabilistic forecast or also called a possible scenario. Concerning the influence on climate, I think we are unable at the moment to make a realistic assessment to what will be the consequence, since many processes are still poorly understood and modelled.
Biosketch
Prof. Ilya Usoskin works at the University of Oulu (Finland). He is vice-Director of the Finnish National Centre of Excellence in Research on Solar Long-term Variability and Effects (ReSoLVE). He focuses his research on Solar and Solar-terrestrial physics as well as in Cosmic Ray physics. He is a member of numerous scientific commissions and panels, reviewer and member of editorial boards for a number of professional journals, and an organizer of scientific conferences and symposia, including a series of biennial International Symposia in Space Climate. He is an author of more than 200 scientific publications, including 150 peer-review ones, among those a dozen of invited reviews and book chapters.
What will happen during a new Maunder Minimum? « Climate Dialogue
I prefer to read what real scientists have to say. Not frauds on internet message boards.