What was done
The authors correlated sea-salt concentrations in an ice core retrieved from the Penny Ice Cap of Baffin Island with monthly data for Baffin Bay spring sea-ice extent over the period 1901-1990, deriving a relationship that was "further supported by decadal and century scale comparison with other paleoclimate records of eastern Arctic climate change over the last 700 years," from which they subsequently constructed a 700-year record of Baffin Bay spring sea-ice extent based on sea-salt concentrations deeper in the ice core.

What was learned
The results of the study were indicative of warmer temperatures and the presence of much less sea ice at the beginning of the 20th century.  From about 1930 onward, however, spring sea-ice extent rose significantly.  In fact, the authors say that the last few decades of sea-ice extent actually "lie within Little Ice Age variability and correspond to instrumental records of lower temperatures in the Eastern Canadian Arctic over the past three decades."

What it means
In a part of the high-latitude region of the planet where theoretical CO2-induced global warming is predicted to be most evident, real-world data reveal a century-long climatic trend that is just the opposite of what climate alarmists claim should have happened over this period.  In fact, it has gotten so cold in this region of the world that Baffin Bay sea-ice extent has returned to conditions characteristic of the Little Ice Age.  And, of course, the warmest conditions of the past seven centuries are found in the earliest portion of the record, near the end of the Medieval Warm Period.