What was done
The authors analyzed dinoflagellate cyst assemblages in two sediment cores from the southeastern Barents Sea - one spanning a period of 8300 years and one spanning a period of 4400 years - obtaining information about sea-surface salinity, temperature and ice cover throughout the mid- to late-Holocene.

What was learned
The longer of the two cores indicated a warm interval from about 8000 to 3000 years before present, followed by cooling pulses coincident with lowered salinity and extended ice cover in the vicinity of 5000, 3500 and 2500 years ago.  The shorter core additionally revealed cooling pulses at tentative dates of 1400, 300 and 100 years before present.  For the bulk of the past 4400 years, however, ice cover lasted only two to three months per year, as opposed to the modern mean of 4.3 months per year.  In addition, August temperatures ranged between 6 and 8°C, significantly warmer than the present mean of 4.6°C.

During the initial warm interval, there were no signs of significant climatic variability.  The following cool periods, however, were much less stable.  The authors note that their findings correlate with palaeoclimatic reconstructions from northwestern Eurasia and suggest "that sea-surface variations in the Barents Sea reflect large-scale changes in atmospheric and oceanic interactions between the North Atlantic and the Arctic."

What it means
Once again, we have evidence of considerably warmer temperatures than those of today over much of the past few thousand years - including a period of time coeval with the Medieval Warm Period - in the southeastern Barents Sea, which conditions are said to be reflective of conditions throughout northwestern Eurasia.  And once again, therefore, we have the testimony of the very-real world refuting the climate alarmist claim that it is currently warmer than it has been at any time during the past millennium.  Ah, there's nothing like DATA!