Over the last few days there has been much discussion in the newspapers and the Internet of a new paper about ‘the pause’ (in global warming), the authors arguing that it is the trade winds which are doing it, and that when the winds stop the warming will return with a vengeance. That paper will be addressed in my post on Friday, but in preparation I want to look again at the GCMs, the global circulation climate models that are at the heart of all the prognostications about the future of the planet’s climate,rainfall, drought, frying, and all the rest of it.
I wrote about this subject a few months ago, and I’m going to illustrate what follows with the newest version of a graph that I used then, constructed by Dr Roy Spencer, of the UAH satellite temperature dataset. It looks like this:
The ‘spaghetti’ trails describe the proposed temperature up to 2030 from the 90 models of the Coupled Model Intercomparison Project Phase 5 set of climate models, and they are the ones on which the IPCC largely relied for its 5th Assessment Report. The black dotted line represents the mean of these projections, while the green dots show the actual surface temperature observations up to the end of 2013, and the blue dots the satellite measurements of the lower troposphere (the lowest part of the atmosphere containing clouds, water vapour and aerosols). The zero point on the vertical axis is the global temperature anomaly, not measured against the customary 1960 to 1990 baseline, but against a much shorter four-year 1979-1983 average.
While the models and observations were close together in 1998, by the end of 2013 only a couple of models were near actual observations, no matter which dataset, and it is worth noting that HadCRUT4 comes from the Hadley Centre, and can be thought of as the dataset most preferred by the AGW orthodox. Dr Spencer says: I am growing weary of the variety of emotional, misleading, and policy-useless statements like “most warming since the 1950s is human caused” or “97% of climate scientists agree humans are contributing to warming”, neither of which leads to the conclusion we need to substantially increase energy prices and freeze and starve more poor people to death for the greater good. Yet, that is the direction we are heading.
The important message from the graph, as far as Dr Spencer is concerned, is that the climate models that governments base policy decisions on have failed miserably. They are supposed to tell us what is in store for us ten, twenty and more years down the track. I like to stick with global warming, because it is the base of the AGW scare. If temperatures are to rise, say the modellers, then they can tell us all sorts of worrying things that might follow. But if the models can’t even predict the trend of the actual warming that has occurred, why are they of any use in developing useful policies?
He goes on: Whether humans are the cause of 100% of the observed warming or not, the conclusion is that global warming isn’t as bad as was predicted. That should have major policy implications … assuming policy is still informed by facts more than emotions and political aspirations. And if humans are the cause of only, say, 50% of the warming (e.g. our published paper), then there is even less reason to force expensive and prosperity-destroying energy policies down our throats.
His final paragraph sets the scene for the paper I want to discuss next time, because it is about the oceans and their character:
And even if the extra energy is being stored in the deep ocean (if you have faith in long-term measured warming trends of thousandths or hundredths of a degree), I say “great!”. Because that extra heat is in the form of a tiny temperature change spread throughout an unimaginably large heat sink, which can never have an appreciable effect on future surface climate. If the deep ocean ends up averaging 4.1 deg. C, rather than 4.0 deg. C, it won’t really matter.
The problem for the orthodox is that the models aren’t much chop, so it is important for those who believe in them to find reasons why they really are good but something unexpected has darkened their horizon. The new paper is a good example. By the way, Dr Spencer’s own paper, highlighted above, is a most worthwhile read, on the ‘climate sensitivity’ issue.
[I saw the need to add 'climate' in the title of this post, after I had published it ...]