I notice that David Rose has an article in the Daily Mail that is mainly about Government ministers and eco-zealots, but that also includes a discussion of Judith Curry’s recent Stadium Wave paper. I haven’t read the paper in great detail, but as far as I can tell it is really just an attempt to identify signals in various bits of climate data, and doesn’t really include any physical mechanisms for explaining these signals.
The David Rose article says
According to Curry and Wyatt, the theory may explain both the warming pause and why the computer models did not forecast it.
It also means that a large proportion of the warming that did occur in the years before the pause was due not to greenhouse gas emissions, but to the same cyclical wave.
The issue I have with this interpretation is that the stadium wave idea seems to provide no physical mechanism for why there are these signals in the climate data. It is simply an attempt to identify cycles. Nothing fundamentally wrong with that, but it does seem to be just a complicated curve fitting exercise. Also, Judith Curry herself says
The paper is about natural internal variability, it says absolutely nothing about AGW. The IPCC treats natural internal variability as ‘noise’; we argue that it is the fundamental climate signal on decadal to century time scales, with external forcing projecting onto these modes.
So, it seems to me that if these stadium wave oscillations are real (and, to be honest, I’m not convinced that they are) then they may well explain periods when the surface warming was slower than expected (as it is currently) and periods when it was faster. It might explain why the Arctic sea ice is declining faster than expected. What it cannot do is explain why the energy in the climate system, as a whole, continues to increase. Internal variability cannot do that. It can move energy around in the climate system, but it cannot increase the overall energy. That requires some kind of change in external forcing. This is a fairly basic concept that even David Rose should be able to understand.
One might think that David Rose has mis-interpreted what the authors have actually said about the stadium wave paper, but I’m not sure that would be a fair accusation. He quotes one of the authors (Marcia Wyatt) as saying
‘The stadium wave forecasts that sea ice will recover from its recent minimum.’ The record low seen in 2012, followed by the large increase in 2013, is consistent with the theory, she said
All I can really say to that is one data point does not make a trend. Given the low value in 2012, the 2013 value was almost certainly going to higher. Using that to claim that it is consistent with the theory is a little disingenuous. I would also argue that this isn’t technically a theory, it is simply a complicated curve fitting exercise. A theory would normally require some kind of physical basis, not just a time-dependent equation.
Wyatt apparently also said
‘The stadium wave signal predicts that the current pause in global warming could extend into the 2030s,’
That would be quite remarkable if true. Given the rate we’re adding CO2 to the atmosphere, the anthropogenic forcings will likely increase by 0.5Wm-2 by the mid-2030s. We currently have an energy imbalance of around 0.7Wm-2. For the “pause” to continue into the 2030s, would require that an ever increasing fraction of this excess energy be sequestered in the oceans. Possible, I guess, but not very likely.
It’s quite frustrating, but not surprising, that David Rose would overplay the significance of Judith Curry and Marcia Wyatt’s paper. It’s also a little frustrating that they will likely do nothing to correct this mis-interpretation. They will probably argue, if they say anything, that he hasn’t mis-represtented their work. This may, technically, be true but it would be nice if they could at least acknowledge that the stadium wave has virtually no significance with respect to long-term anthropogenic global warming. That continues as expected and will carry on doing so as we continue to increase atmospheric CO2 concentrations.