Real Climate Doubletalk – Blog Food
Posted by Jeff Id on January 24, 2009
This is why I don’t respond to references from real climate. They will say anything to support their theory of the moment is. Their latest is in direct contradiction to their latest from February, yet they already knew all of it and it is all perfectly consistent with ‘accepted’ global warming.
Here’s an quote by RC on the recent statistical paper used to “predict” that past temperatures were cooler in the antarctic.
Some comment is warranted on whether our results have bearing on the various model projections of future climate change. As we discuss in the paper, fully-coupled ocean-atmosphere models don’t tend to agree with one another very well in the Antarctic. They all show an overall warming trend, but they differ significantly in the spatial structure. As nicely summarized in a paper by Connolley and Bracegirdle in GRL, the models also vary greatly in their sea ice distributions, and this is clearly related to thetemperature distributions.
and another piece of gold.
That means that a sensible projection of future Antarctic temperature change — at anything smaller than the continental scale — can only be based on looking at the mean and variation of ensemble runs, and/or the averages of many models.
I do love that one. Individual models stink so let’s average a bunch together until we get a flat uprising trend that is nearly guaranteed to give a better r value.
Well what did they say in February 08
Despite the recent announcement that the discharge from some Antarctic glaciers is accelerating, we often hear people remarking that parts of Antarctica are getting colder, and indeed the ice pack in the Southern Ocean around Antarctica has actually been getting bigger. Doesn’t this contradict the calculations that greenhouse gases are warming the globe? Not at all, because a cold Antarctica is just what calculations predict… and have predicted for the past quarter century.
The article finishes up with this.
The pioneer climate modelers Kirk Bryan and Syukuro Manabe took up the question with a more detailed model that revealed an additional effect. In the Southern Ocean around Antarctica the mixing of water went deeper than in Northern waters, so more volumes of water were brought into play earlier. In their model, around Antarctica “there is no warming at the sea surface, and even a slight cooling over the 50-year duration of the experiment.” (4) In the twenty years since, computer models have improved by orders of magnitude, but they continue to show that Antarctica cannot be expected to warm up very significantly until long after the rest of the world’s climate is radically changed.
Bottom line: A cold Antarctica and Southern Ocean do not contradict our models of global warming. For a long time the models have predicted just that.
A comment from gavin in the thread from the link above.
[Response: That’s exactly Spencer’s point. Models did improve once they had dynamic oceans (which the Hansen 1988 runs did not). And the predictions for the Antarctic dropped. But that happened a while back. - gavin]
And here’ s another one from 2006 which discusses polar amplification. It goes on quite a bit about the antarctic and arctic but here’s a small piece.
Due to the successful treaty to reduce ozone-depleting chlorofluorocarbons (CFCs) emissions, ozone levels in the stratosphere are expected to recover over Antarctica by about 2040, so eventually Antarctica begins to warm somewhat in climate model predictions of the 21st century (see Fig 2) (WMO, 2002).
I had to add this one where gavin was responding to some skepticism about models in the comment thread second link above.
[Response: First off, the ensemble mean or long time scale is not the field to compare to the single realisation of the real world (as discussed previously). Secondly, all of the radiosonde data set are being reassessed to deal with known biases. If those revisions end up looking more like the model means, will you then accept that the models have some validity? I don’t think we will have that long to wait… - gavin]
So in February we shouldn’t compare the ensemble mean to the data now we should.