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A jump into the country's largest lake used to send swimmers running for their wetsuits to brave the frigid temperatures; not the case earlier this week, when six swimmers left their wetsuits behind to prove a point about climate change while they also changed - chased a swimming record. For Minnesota Public Radio, Dan Kraker reports.
(SOUNDBITE OF WAVES CRASHING)
DAN KRAKER, BYLINE: Early Wednesday morning, Craig Collins emerged dripping from Lake Superior wearing just a small swimsuit and a yellow swim cap. The 64-year-old from Minneapolis grinned as he jogged onto the beach in Duluth.
(CHEERING)
CRAIG COLLINS: I love this so much - open water, swimming.
KRAKER: Collins and his teammates swam through the night in hourlong shifts. It took nearly 24 hours to swim 48 miles down the western shore of the lake. That set a record for the longest-distance relay swim in Lake Superior. The water was a tolerable 62 degrees. That's in a lake where temperatures can plunge into the 30s and 40s, even in the summer. Karen Zemlin from the Twin Cities says what made it tough were waves that swelled to 5 feet.
KAREN ZEMLIN: Which was super challenging but amazing because if they were heading the other direction, we wouldn't have made it. But heading towards Duluth, we could sometimes catch the top of that that 5-foot breaker and just feel like a dolphin.
KRAKER: Zemlin knows all about cold water temperatures. She tried eight years ago to swim across the English Channel, the waterway between the southern part of England and France. But she pulled out with hypothermia.
ZEMLIN: I couldn't remember it was France anymore. I knew I wanted to get over there, but I couldn't have told you it was France.
KRAKER: Zemlin knew she needed more time training in cold water, so she came to Lake Superior, where she could find the temperatures she needed.
ZEMLIN: I tell people if I'm swimming in water 55 degrees or below, it's like having an ice cream headache in my arms and my legs. So it's, like, that tingly, really sore feeling that you get in your forehead when you eat your ice cream too fast (laughter).
KRAKER: And the lake's cold temperatures apparently helped. When she returned to swim the English Channel again in 2019, she not only made it across; she set a record for women over 50. But Zemlin's Lake Superior training pool isn't what it used to be. Jay Austin, a professor at the Large Lakes Observatory at the University of Minnesota Duluth, says Lake Superior is one of the fastest-warming lakes in the world.
JAY AUSTIN: Recent years, since 1998, tend to be on the order of four to five degrees warmer than pre-1998.
KRAKER: A warmer lake, which Austin says makes the no-wetsuit decision by the six swimmers palatable.
AUSTIN: They're dancing right above the threshold of where it's really feasible to do something like this.
KRAKER: The change is due largely to warmer winters. That's led to a sharp decline in ice coverage on the Great Lakes, thus warmer water in the summers. Better swimming conditions, yes, but it also causes major ecological impacts. For the very first time, toxic algae blooms have appeared in Lake Superior. The swimmers' example of how climate change is impacting one of the world's largest freshwater lakes will be featured in an upcoming documentary. A film crew followed the team's journey down the western shore of the lake.
UNIDENTIFIED PERSON: Cheers.
(CHEERING)
KRAKER: For 51-year-old swimmer Casey McGrath of Minneapolis, the experience was bittersweet.
CASEY MCGRATH: It's a cool experience that we were able to to to have it, but really in some ways shouldn't have been able to do it, not without wetsuits, anyway.
KRAKER: Scientists say wetsuits will still often be needed, but as the climate warms, there will be more and more years when it's surprisingly comfortable to swim in what is often a bitterly cold Lake Superior.
For NPR News, I'm Dan Kraker in Duluth. Transcript provided by NPR, Copyright NPR.
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