Global sea surface temperature and model projections, with Bob Tisdale

A couple of days ago at WUWT Bob Tisdale posted a whole heap of charts of sea surface temperature and compared them to CMIP5 models (archived here). He was doing his usual thing of complaining the climate models don't model weather. He wrote:

The climate models used by the Intergovernmental Panel on Climate Change (IPCC) are not simulating climate as it exists on Earth. 

What he was really complaining about was that:

The multi-model mean of climate models used by the Intergovernmental Panel on Climate Change (IPCC) are not simulating climate as it exists on Earth. year to year variations in the weather as recorded by the older version of Reynold's OI v2 data, when looking at some sections of the ocean. 

Well, they aren't meant to do that. Climate models are for, you guessed it, climate not weather. The CMIP5 models are used for climate projections as well as learning more about particular aspects of climate. They are pretty good when it comes to global projections. Not as good (but not that bad) when looking at large areas like entire oceans. They are not intended to be used for weather forecasts. (Bob wants them to time ENSO events at the same time as they happen. That won't happen. There are other models specially developed for localised projections looking ahead a few months.)

There were some charts that were noticeable by their absence, so I figured I'd fill in the gaps in his article.

Tree ring growth vs latewood density: Pat'n Chip get lost in the forest at WUWT

Anthony Watts has a "guest essay" by Pat'n Chip (archived here, latest update here), the duo from the CATO Institute. (Part of their job seems to be to spread disinformation about climate science. It's a good lark. Money for jam. They don't have to do much except spend a few minutes every now and then writing stuff and nonsense.)

Today's serving has a woody flavour. They are claiming that a new paper in GRL, by Martin Tingley and colleagues, contradicts a paper by Michael Mann. Michael Mann says, no. That's wrong.

To summarise

As suggested by Steve Bloom in the comments, here are the main points as I see them:

• Tree ring growth reconstructions do not register the sudden (short-lived) drop in temperature following very large volcanic eruptions of the past millennia. This has implications for estimates of climate sensitivity based on paleoclimatology. (Mann12)
• Latewood density measures exaggerate the drop in temperature following large-ish recent volcanic eruptions, Krakatau and Novarupta. (Tingley14)
• The new paper by Martin Tingley et al complements, rather than contradicts, the 2012 paper by Mann et al. 
• In dendrochronology, density is not the same as tree ring growth and one does not necessarily follow the same pattern as the other.

Initial impressions

Before I discovered Michael Mann's Huff Post article, I looked at the Mann paper and the abstract of the Tingley paper and at first glance it looked to me as if the papers were about different things. Or at least about different volcanic eruptions. I had some questions, though, because both papers were looking at how the sign of a temperature drop after large volcanic eruptions are manifested in tree rings.

So I went to the Tingley paper itself. It's not open access, so unless you can get hold of a copy, you'll have to take what I write at face value. Or you can read what Michael Mann has written about this at Huffington Post.