650,000 years! So, that's around 10 times the time period of modern humans: Homo sapiens. It's about 1/5 the time period of human family existance and 1/100th of the time from the extinction of the dinosaurs- which are thought to caused by an 6 kilometer wide impactor. And about 1/300th of the time from the last period of mass extinction [unlike the somewhat minor extinction of the dinosaurs]. And about 1/1000th of the period in which life evolved beyond the level of microorganisms.
So these finding claim to have determined that during this entire period of 650,000 years, today's levels of CO2 in the antarctic are 27% higher than at any time during this 650,000 years.
Of course in terms recent times [less than million ago] our current period of warming is a bit longer than the norm. And the record shows that CO2 increases follow a warming period and does increase throughout these periods. So that merely the length of time of the current warming could account for some of this increase. There is also no doubt that human activity is adding significant enough amount of CO2 to the atmosphere that it can be measured despite huge swings due natural seasonal variable of global CO2 levels.

One small thing I wonder about is the amount CO2 levels added to Antarctic due to humans living in the Antarctic [something which did not occur other than at modern times]. I'm pretty sure, it's a tiny affect, but of this 27% is possible it's say some fraction is added?

One argument to this might be the dispersion of the CO2 and of the relative small population and human activity in the Antarctic. I put question would CO2 levels be lower in Antarctic if there was no human activity associated with this region [which doesn't mean it's limited to merely small amount of generators and snowmobiles].
The Antarctic lacks a carbon sink due to plant life, but I don't think I would say it's lacking a mechanism which functions as carbon sink- both poles cool ocean water which feeds into the oceans of the world and it seems to me that this could act as large carbon sink [though I can't recall anyone mentioning this and depending up how this works could further reduce any locally added CO2].