"However, tucked away at the end was a rather confused section, where it appears that Lindzen bet Nye that ice cores don't have a resolution better than 2000 years. Now this is an odd claim, and an odder thing to bet on, since Greenland cores (GRIP, GISP2) and Antarctic cores (EPICA DML) have sub-annual resolution in many cases for the isotope (temperature) records, and at least decadal resolution (Law Dome, Siple Dome) for the greenhouse gases (CO2, CH4). It's true that the very longest records (Vostok and Dome-C) have coarser resolution, but surely Lindzen doesn't think they are the only ones that exist?"
Based on that, it would appear that some ice cores could provide data indicating 80-100 ppm CO2 excursions on the century scale -- if they ever happened. Note that this includes EPICA, the 650,000 year long core.
I probably won't be able to reply again until late Monday; have a nice weekend.
The realclimate threads like this: http://www.realclimate.org/index.php?p=221 they always dance around the resolution issue. Your quote from them is a perfect example of the oft-repeated fallacy of juxtaposing high res records onto low res ones to make political points. Obviously their statement that CO2 is the highest in 650,000 years (the first major point in their report) is not supported by ice core evidence because, as Lindzen correctly points out, the old cores have 2k resolution in many cases. It's just the same old song and dance from them.