What was done
In a review of the pertinent scientific literature, the authors "summarize what is known, and unknown, about both Laurentide and alpine glaciation on Baffin Island from the latest Pleistocene through the 20th century."

What was learned
Briner et al. report that the "initial recession of the Laurentide Ice Sheet led to the most distal sites on Baffin Island to become ice free by ~14 ka," and that subsequent "neoglaciation began as early as 6 ka," while "the Little Ice Age seems to have been consistently the time period during which alpine glaciers reached their maximum extents." In addition, they state that "both the glacier and climate proxy data recorded in lacustrine sediments and ice cores (e.g., Fisher et al., 1998; Miller et al., 2005; Anderson et al., 2008) depict the Little Ice Age as the coldest interval on Baffin Island during the Holocene [italics added]."

What it means
Once again - see Barclay et al. (2009) and Menounos et al. (2009) - we have a situation where the Little Ice Age was found to have been the coldest period of the current interglacial [italics added], which suggests (once again) that 20th-century global warming could not have taken the earth into "uncharted" thermal territory, but only back to something similar to what prevailed prior to the Little Ice Age, like the Medieval Warm Period, which was merely a run-of-the-mill relatively warmer period that was still much colder than the several-millennia-long Holocene Thermal Maximum, which Briner et al. report "was several degrees warmer than today [italics added]." Consequently, since much larger temperature changes than the warming experienced over the 20th century occurred at various earlier times in the Holocene, when the air's CO2 content was almost invariant, there is no need - nor even a compelling reason - to invoke the 20th-century increase in the atmosphere's CO2 concentration as the cause of 20th-century warming.

References
Anderson, R.K., Miller, G.H., Briner, J.P., Lifton, N.A. and DeVogel, S.B. 2008. A millennial perspective on Arctic warming from ¹⁴C in quartz and plants emerging beneath ice caps. Geophysical Research Letters 35: L01502.

Barclay, D.J., Wiles, G.C. and Calkin, P.E. 2009. Holocene glacier fluctuations in Alaska. Quaternary Science Reviews 28: 2034-2048.

Fisher, D.A., Koerner, R.M., Bourgeois, J.C., Zielinski, G., Wake, C., Hammer, C.U., Clausen, H.B., Gunderstrup, N., Johnsen, S., Goto-Azuma, K., Hondoh, T., Blake, E. and Gerasimoff, M. 1998. Penny Ice Cap cores, Baffin Island, Canada, and the Wisconsinan Foxe Dome connection: two states of Hudson Bay ice cover. Science 279: 692-695.

Menounos, B., Osborn, G., Clague, J.J. and Luckman, B.H. 2009. Latest Pleistocene and Holocene glacier fluctuations in western Canada. Quaternary Science Reviews 28: 2049-2074.

Miller, G.H., Wolfe, A.P., Briner, J.P., Sauer, P.E. and Nesje, A. 2005. Holocene glaciation and climate evolution of Baffin Island, Arctic Canada. Quaternary Science Reviews 24: 1703-1721.