Quite a good article here looking at the denial argument centered around Greenland ice cores and providing a decent rebuttal of that, plus a good science overview of temperature changes in Greenland based on ice core and recent instrument temperatures.
There is also a useful brief discussion on the process of comparing ice core and instrument temps.
As an aside we're already above Greenland temps during the supposed Medieval Warming Period or Medieval Climate Anomaly (~900-1400 AD). And interesting that medieval period doesn't show up with any great significance in Greenland ice cores.
And we are projected to go way beyond medieval and all Greenland temps of the Holocene and last 10,000 years with the more business as usual future scenarios for greenhouse gas emissions.
"Recent temperatures are clearly higher than any seen in Greenland over the past two millennia."
"Recent temperatures in Greenland are still likely below those experienced in the early Holocene. This is similar to what is found in global Holocene temperature reconstructions, ... , which suggested that “current global temperatures of the past decade have not yet exceeded peak interglacial values, but are warmer than during ~75% of the Holocene temperature history”.
"... if the present rate of warming continues, the Earth should pass well beyond any temperatures experienced in Greenland during the Holocene by 2050."
