Marcott only put out his disclaimer of 'not robust' because of heavy criticism coming from the blogosphere. it was easier to retract his claims rather than defend them and besides, the press releases had already gone out and the paper would be famous in the public eye as a new and improved hockeystick. rebuttals and even retractions of papers arent 'newsworthy' and the public doesnt hear about it.
as far as unprecidented rate of warming in the modern era....in a past thread I showed an analysis of the Vostock (?) ice core that checked all of the 1C temp spikes in our temp range. there were dozens, many with greater than 1C rises, some that lasted longer than 100 years. none of them led to a 'tipping point'. our recent spike actually looked like it could have been the calculated average rather than just another data point. got that? there is nothing special about our temps other than the obcession about CO2 by the doomsayers.
Agreed about Marcott's "honesty".. Don't remember that Vostok type of graph before..
I'm not doubting that our CEra warming is not unique, but I'm doubting that the true RATES of those graphs are accurate. They may paint a picture of relative rates, but maybe not absolute values of either rates or magnitudes..
What is your knowledge of the claimed time resolution on ancient ice cores? I remember all kinds of "alignments" and "corrections" leading to some general statement about 25 -- 50 year at THOSE time scales..
But ice is a very non-linear proxy.. And if temperatures DID spike that high, the melt rates would be severe in those layers --- wouldn't they? How do you control for stuff like that and claim a 25 -- 50 year time resolution over milleniums??
Antarctica ice cores dont have as much of a problem with melt rates as other locations. while I am sure that there could be a problem with the yearly striations, ice cores are likely to be the best long term proxy that we have. antarctic ice is not melting now, the comparisons are between very cold and even more cold. I have a healthy dose of suspicion for all proxy results but if we have to use a proxy this is one of the more robust ones. it shows results that put our recent warming in a very average position.
And these ice cores (from various locations) have shown that CO2 does not drive climate.