Well, that’s certainly odd. The pic is a copy (stolen with no attribution, are you surprised?) of [[http://en.wikipedia.org/wiki/File:Ipcc7.1-mann-moberg-manley.png]] which I uploaded to wiki (once again I’m moved to comment that although the denizens of WUWT pretend that they don’t trust wiki, actually just like everyone else they use it, and forget their scruples whenever convenient. Note also that the current wiki pic has had the green line added by DS). Its from When the IPCC ‘disappeared’ the Medieval Warm Period at WUWT (webcite).
But its had some fake labelling added to it:
* IPCC ’90 has been re-labelled “IPCC 1990-2001”
* MBH99 has been relabelled “IPCC 2001-2003”
At least they managed to label Moberg correctly. Its hard to understand those other labels. “IPCC 1990-2001” is intended to suggest it was first used in 1990, and continued until supplanted in 2001. But we all know that is wrong (apart from all the rest, they’ve airbrushed IPCC ’92 and ’95 [*] out of their picture; ironically, the post at WUWT is ostensibly about IPCC rewriting history; but I suspect that they don’t do irony) and the author of the piece at WUWT knew it too, because he copied it from the wiki page Description of the Medieval Warm Period and Little Ice Age in IPCC reports which explains, with references, where it all comes from. So, he was deliberately lying to his audience. 2001-2003 makes no sense either.
But more amusingly, all his audience is so incompetent that they fail to realise they are being lied to. Although the information is easily available on the web, not one of them has the initiative or intelligence to look for themselves – they just sit there being fed lies, and lapping them up. One, Jay, gets close: By the by – the 1990-2001 plot is of data for a small bit of Europe, not the Northern Hemisphere. Hence the MWP looking less of a feature in later plots – because the evidence for the whole Northern Hemisphere is that the MWP was rather less of a feature than it was in a small bit of Europe. But even this minor correction is too much for some, garnering: You’re out of touch and simply regurgitating RC’s 2007 lying rubbish. Do some homework. Later, I think its clear that Jay has realised that the “1990-2001” line is mislabelled, and can’t be directly compared with the other two: The data plot with the strong MWP in fig 1. (labeled IPCC 1990-2001) is a temperature reconstruction for the United Kingdom, a small area in North West Europe. The remaining two data plots in fig 1. are temperature reconstructions for the entire Northern Hemisphere. but the post author (Frank Lansner) refuses to believe this: but please document your UK-claim, i would like to see that, ok?. That’s weird: he’s copied the picture from wiki, so he knows he is wrong. Is he just trying to brazen it out hoping that Jay doesn’t know the exact source?
No, I’m wrong. By 13th March (the post is from the tenth, so that’s 3 days of comments before anyone really gets it), Christoffer Bugge Harder shows up to say its all nonsense: I honestly think that all your questions can be answered by simply looking at this wikipedia link: http://en.wikipedia.org/wiki/Description of the Medieval Warm Period and Little Ice Age in IPCC reports The reason why the IPCC conclusions have changed since 1990 is quite simply that back then, no global multiproxy reconstructions with data from before about 1400 existed… and so on; all the obvious truth. Wittily, this is immeadiately followed by Caleb who tells CBH: You need to wake up and realize you’ve been fooled by a hoax.
CBH keeps pushing Lansner: <i.Do you realise that the IPCC 1990-2001 graph is a purely schematic one from which no quantitative conclusions can be drawn? You do not seem to. who doesn’t answer that point, but does say CBH, you write “You appear to think that the IPCC pre-2001 graph is based on the “1976-2000 proxies” you list?” No, this is by Lamb, former head of CRU. Its based mostly on English data as I have understood it. Note this is precisely the point he has denied earlier as a debating trick. The discussion the segues off into boreholes but Lansner never gives an honest answer, or even addresses the real point.
Oh, and don’t get me started on how incompetent his fig 2 is.
[*] Note: I tend to call it ’95, because that is what it calls itself. But it was published in ’96, I think.