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Climate Column: A warmer Lake Superior is becoming normal

In mid-August, Lake Superior surface water temperatures around Two Harbors hovered in the mid-60s. I know, because I swim in the waves almost every day, usually for 10-20 minutes. Before I go in, I take a thermometer and hold it in the waves at my feet. Then I know what I am getting into.

In 2010 we were out in the open lake in July. Water temperatures 4 feet under the surface hit 72 degrees. Knowing that the long term average high temperature of the surface of Lake Superior is 59 degrees, a 72 degree reading got our attention. We went swimming, assuming that the comfortingly frigid waters would soon return. That was before we were attuned to climate change, a hallmark of which is that the extraordinary becomes commonplace.

Mark has been keeping track of open lake water temperatures ever since that swim. From 2010-2013, 4-feet-under temperatures got into the 70s each summer for a substantial period of time. After the record-breaking cold winter of 2013-14 with its nearly 100 percent ice cover of Lake Superior, the temperatures dropped towards the long term averages, and never got into the 70s. But with the trend towards milder winters and less ice cover, surface temperatures are rising inexorably. Last summer, by the beginning of September, a fisherman on the south shore told us that the temperatures had reached 84 degrees. "There was no [trout] fishing to be had," he said.

How quickly we are adapting to the whole notion of change. Change has become the norm. In the Aug. 11 News-Chronicle article of Kate Thomasen's rescue swim out in Burlington Bay, there was not one mention of what would have been the main thrust of that story just 10 years ago — the frigidity of the water. Swimming out to get a child on a float was challenging and brave, but it was not life-threatening purely because of water temperatures. Now that's a change — all the more astonishing because no one seemed to notice.

After I swim, I walk home past Harbor Apartments. There are usually a few friendly elderly residents hanging out in front, and inevitably they ask me how the water is. "Chilly!" I say, or "Not bad today!" They always laugh, that we-know-better laugh that reminds me that they know I'm insane to jump in the icy waters of Lake Superior. I could tell them that the water is in the mid-60s; it doesn't matter. They are slower to adjust to the new reality. Or maybe I'm crazy even to swim in 65 degree water.

Katya Gordon of Two Harbors is a member of the Duluth/North Shore chapter of the Citizens Climate Lobby. She writes a regular column on climate change for the News-Chronicle.