Ice freeze data from two lakes suggest warming winters since the end of the Little Ice Age

Not to be overtly obtuse, as I am not a climatologist nor a meteorologist such as yourself, but does it really come as a surprise that the ice out dates have become earlier since the Little ICE AGE?
Actually, the Little Ice Age(s) were fairly telling, since all but the most recent cooling period were prior to the Industrial Revolution. All three correspond to significant volcanic eruptions, the most recent the Mt Tambora eruption of 1815 that made 1816 come to be known as the "year without a summer".
Others think that decreased solar activity or disruptions in ocean currents. Just goes to show that nature is bigger than mankind, no matter how much hubris he accumulates.

That is not very surprising SSgt (Join to see) since global warming and cooling have alternated over the millennia long before any possible human activity could be blamed. Of course the cycles are not uniform and they tend to be much longer than the lifetimes of creatures which inhabit this planet.
The cycles in this article only date back to the 15th century in japan which is relatively recent in terms of geological history.