That's actually a pretty wide range. But does it refute any sort of consensus? I looked up what the AR4 had to say. There wasn't much, but in Chap 7, sec 220.127.116.11, I found this:
“A 1°C increase in sea surface temperature produces an increase in pCO2 of 6.9 to 10.2 ppm after 100 to 1,000 years (Heinze et al., 2003; see also Broecker and Peng, 1986; Plattner et al., 2001). “
That seems quite within the range Frank et al find. Yet people who suggest some pillar of AGW has fallen say that recent estimates were up to 40 ppmv/C. Lubos Motl had cited that figure, so I put the IPCC figure to him. He cited this 2006 paper by Scheffer, Brovkin and Cox as the source of the 40 ppmv/C claim.
I looked up that paper. They had deduced their estimate from the CO2 response to the LIA, and said
we arrive at an estimated carbon sensitivity (α) to temperature of 41 (following Mann and Jones) to 12 (following Moberg et al) ppmv CO2°C.
A rather ambivalent figure to be refuting.