This makes sense - we've known for a long time that glaciers in Europe and the Sierra Nevada reached a maximum at the end of the Mini Ice Age. In the 18th century, the curate of Argentiere (near Chamonix) used to go out annually to perform an exorcism on the glacier that was getting closer and closer to the town. And guess what? It worked. By the time I started going there in 1992, the glacier was a couple km away and has receded a lot more since.
Similarly, the glaciers that John Muir found that proved he was right about the glaciation in the Sierra Nevada started disappearing almost as soon as he found them (or rather, were perhaps already shrinking). The last one in Yosemite ceased to be a glacier a few years ago.
All that to say that if glaciers reached a local maximum in the early 19th century, it makes sense that sea level would have reached a local minimum.
The frightening part is how that melting of glaciers began to accelerate in the 1990s. It was one of those things that people with long memories had noticed and then it became one of those things you couldn't avoid. I remember one day thinking a jet was going over and it was the constant rock and ice fall from a melting face near Chamonix a km from where we were climbing.
