What was done
Sediment cores were extracted from Lake JR01 (69°54'N, 95°4.2'W) on the Boothia Peninsula, Nunavut, Canada, using a 5-cm diameter Livinstone corer, with the authors careful to note that "the uppermost part of the sediment was sampled in a plastic tube with piston to ensure that the sediment-water interface was collected," while further stating that "the upper 20 cm of sediment were sub-sampled into plastic bags at 0.5-cm intervals." Then, from the fossil pollen assemblages thereby derived, July temperatures were estimated "using the modern analog technique," as per Sawada (2006).

What was learned
Zabenskie and Gajewski report that "maximum estimated July temperatures were reached between 5800 and 3000 cal yr BP, at which time they exceeded present-day values." Thereafter, temperatures decreased, but with "a short warming," which they say "could be interpreted as the Medieval Warm Period," or MWP, which they identified as occurring "between 900 and 750 cal yr BP." Following this latter period of warmth, they found that "temperatures cooled during the Little Ice Age," as pollen percentages "returned to their values before the [MWP] warming." Last of all, during the final 150 years of the record, a "diverse and productive diatom flora" was observed. However, as the two researchers continue, "July temperatures reconstructed using the modern analog technique remained stable during this time," which suggests that the Lake JR01 region of the Boothia Peninsula is currently not as warm as it was during the MWP.

What it means
Once again (see our Medieval Warm Period Project for many more examples), we have another study that finds current temperatures -- which climate alarmists claim to be unprecedented over the last two millennia or more -- to actually be lower than what they were only 750-900 years ago, when there was much less CO2 in the air than there is today, which suggests that a repeat performance of whatever was responsible for the warmth of that earlier period could easily be the source of today's lesser warmth.

Reference
Sawada, M. 2006. An open source implementation of the Modern Analog Technique (MAT) within the R computing environment. Computers & Geosciences 32: 818-833.