IPCC reviewer: ‘No one ever claimed that climate models could predict all these decadal wiggles’

The BBC reports the comments of warmist prof John Shepherd of the University of Southampton:

As expected, the main message is still the same: the evidence is very clear that the world is warming. Natural changes and fluctuations do occur but they are relatively small. There are still uncertainties but the signal is clear enough to justify action: in fact we need less talk and more action.

Uncertainty is a reason to be cautious, but not a reason to do nothing. On the contrary, uncertainty is a reason for taking action to avoid possible serious risks. The recent slow-down in warming is interesting, but it may still be just a wiggle, maybe caused by a natural cycle in the ocean. If so we should expect more rapid warming in a few years time.

There is no reason whatever to suppose that the slow-down is permanent: these things have happened before (e.g. 1950 to 1970), and no-one ever claimed that climate models could predict all these decadal wiggles.

Read more…

15 thoughts on “IPCC reviewer: ‘No one ever claimed that climate models could predict all these decadal wiggles’”

  1. Why not just say that your models are incapable of forecasting climate change with any accuracy since it is the “wiggles” that make a huge difference in the outcome.

  2. Check this out, on Coyote blog Warren Mayer came up with his own simulation, it involves only two graphs, one based on normal temperature change rate (with about 1/2 a degree due to CO2) and the other based on normal decadal oscillations. He created it 6 years ago, and so far it is right on the money. It also predicts limited cooling until 2030. It isn’t hard to do this stuff, but when you assume everything is carbon and ignore everything else, then yeah it becomes difficult.


    It can be done if you don’t have a political agenda. Warren is not a climate scientist and hit it on the nail.

  3. The modellers may never have claimed that the models would predict everything, but the watermelons sure did. Then proclaimed everything was a validation of the models. And then they’re surprised that their credibility suffers.

  4. You can certainly be more likely to be accurate if you don’t have bias, but you’re still trying to predict future performance based on past performance in a chaotic system when you don’t have all of the relevant variables to start with. To further complicate matters, mankind is a variable, as is all other life. As climate changes so too does life in a dynamic and inherently unpredictable way. Even worse, life’s climate impacting behavior is not solely dependent on climate. Reduction in prey animal population can drive the movements of a pack of dogs which in turn causes a colony of beavers to move which can change the course of a river leading to silt deposition in some areas and erosion in others changing the shape of a coastline enough to shift where storm surge floods homes meaning a section of town that’s normally safe gets destroyed. New construction takes place based on the new shape of the coastline as well as many other market forces. Availability of materials and even social trends will dictate the color of the roofs on all the new buildings determining whether they’re reflective or absorptive.

    The lazy, goal-driven climatologist is inclined to simply dismiss all of the unknowable variables as self-cancelling, but there is no logical or mathematical reason to assume that. The only honest answer is “we cannot know.” Anyone telling you different is probably selling something.

  5. When you have to define a decade as 17 years to make your explanation sound reasonable, you’re on thinner ice than the Arctic Ocean. And in the interest of full disclosure, there is also no reason whatsoever to suppose that the slow down is temporary or that it is not precedent to cooling. These warming and cooling periods also have a centuries long periodicity to them and they’re looking at 100 years of just one of those warming periods and projecting that as the final trend.

  6. The ‘wiggles’ are orders of magnitude larger than the ‘trends’ your models forecast, and therefore far more important for the environment and human activity (heating, cooling, farming, etc.). Until you have a model that can accurately forecast the wiggles, you have only models that are making unimportant statements.

  7. In actual environmental compliance, there’s a rule. If you can’t use it for you, then they can’t use it against you. So a non-certified analyzer that hasn’t been calibrated in two months can’t be used to prove that you were in compliance with your emission limits, but it can’t be used to prove that you were out of compliance either. Since they trumpeted every maximum as a validation, we have every right to trumpet minimums as falsifications.

  8. When the Sun switches from hydrogen to helium burning won’t it expand greatly heating up the planet and even destroying it in the process. I think ultimately in about 2 billion years, we are doomed to global warming.

  9. I haven’t liked the Wiggles nearly as much since Greg left. Saw one of the last concerts with Greg in the group. Toot toot Chugga chugga big ted car …

  10. “On the contrary, uncertainty is a reason for taking action to avoid possible serious risks.”

    So, the more uncertain we are, the more action we should take?

    Or he’s a moron making a stupid argument from consequences, and the BBC editors are too stupid to recognize the fallacy.

Comments are closed.