Lake Mendota doesn't freeze over for as long as it used to.

[Red Pest]

1. I remember taking monthly water and sediment samples during 1973-1974 for my MS thesis

During the winter months I walked out onto the middle of University Bay (hauling my sledge with various instruments) and had to use a human powered ice auger (I was the human power) to drill through 2-3 ft (60-90 cm) of ice to be able to collect my water and sediment samples and get temperature and oxygen profiles of the water column. My research was to examine the ecology of methanogenic microbes (archaea). I was able to isolate a methanogen (Methanosarcina) from the sediment, which I used in studies of its metabolism.

The data provided above in the post clearly indicate that after 1978, the duration of ice diminished and continues to diminish. More evidence that global warming is real. Thanks for posting.