We have already seen many examples of how the IPCC describes research that supports its point of view, but either ignores completely or disparages research that does not. Here is another good example.

S.K. Solanki et al., Unusual activity of the Sun during recent decades compared to the previous 11,000 years. Nature 431, 1084-1087 (2004). In the abstract, this paper says: "Here we report a reconstruction of the sunspot number covering the past 11,400 years, based on dendrochronologically dated radiocarbon concentrations. .... According to our reconstruction, the level of solar activity during the past 70 years is exceptional, and the previous period of equally high activity occurred more than 8,000 years ago.... Although the rarity of the current episode of high average sunspot numbers may indicate that the Sun has contributed to the unusual climate change during the twentieth century, we point out that solar variability is unlikely to have been the dominant cause of the strong warming during the past three decades."

Here is a plot from the paper:

This paper was followed by a 'Brief Communication Arising':

R. Muscheler et al, Climate:  How unusual is today's solar activity? Nature 436, E3-E4 (2005) which says that "our extended analysis of the radiocarbon record reveals several periods during past centuries in which the strength of the magnetic field in the solar wind was similar to, or even higher than, that of today",

and a response by the original authors,

S.K. Solanki et al., Climate:  How unusual is today's solar activity? (reply) Nature 436, E4-E5 (2005) saying "this claim is based on a problematic normalization and is in conflict with independent results, such as the ⁴⁴Ti activity in meteorites and the ¹⁰Be concentration in ice cores."

Now how does IPCC AR4 report this? Here is the paragraph from Chapter 6, p. 478:

"More recent studies utilise physics-based models to estimate solar activity from the production rate of cosmogenic isotopes taking into account nonlinearities between isotope production and the Sun’s open magnetic flux and variations in the geomagnetic field (Solanki et al., 2004; Muscheler et al., 2005). Following this approach, Solanki et al. (2004) suggested that the current level of solar activity has been without precedent over the last 8 kyr. This is contradicted by a more recent analysis linking the isotope proxy records to instrumental data that identifies, for the last millennium, three periods (around AD 1785, 1600 and 1140) when solar activity was as high, or higher, than in the satellite era (Muscheler et al., 2006)."

Now can you guess: who was a contributing author to chapter 6, Solanki or Muscheler? Are Solanki or Usoskin (his coauthor and author of similar studies) amongst the reviewers? 

Note that not only does the IPCC falsely imply that Solanki is wrong and Muscheler right, they also do not even refer to Solanki's response. Instead, they refer to another paper by Muscheler (in fact the IPCC cannot even get their references right - there is no Muscheler et al 2006 in the reference list, presumably 2007 is meant).  This later paper of Muscheler et al was in turn criticised by a post-AR4 paper, E. Bard et al, Quaternary Science Reviews 26, 2301–2308 (2007), which points out that there are problems with the data used by Muscheler, and that these problems had already been described in the literature.

The above statement by the IPCC is clearly nonsense, since in particular the period around 1600 was the start of the Maunder Minimum, a well known period of exceptionally low solar activity. 

An amusing additional irony to this story is that the paper by Solanki et al. that the IPCC is so keen to criticize, for its sacriligious suggestion that the Sun might have some slight influence on the Earths climate, is in part based on reconstructions from measurements of carbon levels from tree rings. Thus the IPCC is quite happy to criticize a tree-ring 'hockey stick' reconstruction that does not conform to the IPCC agenda, and equally keen to support a tree-ring 'hockey stick' reconstruction that does conform to the IPCC agenda.