MINNEAPOLIS (WCCO) — Based on surface area, it’s the largest fresh water lake in the world.

And thousands of people visit Lake Superior every year.

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But as old as it is, the lake is still evolving.

John Lauritsen shows us how climate change and warmer temperatures are changing the lake.

There are countless reasons why people from around the world are drawn to a lake that formed nearly a billion years ago.

“It has a personality just like a person does. So somedays it’s really mad and all stirred up and brown. Other days it’s like glass and smooth and blue,” said Nancy Grassinger, a frequent Lake Superior visitor.

(credit: CBS)

The lake’s personality is intriguing to Jay Austin as well. He’s a professor at University of Minnesota Duluth’s Large Lakes Observatory, which studies the health of lakes around the world.

“Not just Superior but all of the upper Great Lakes have significant trends over the last several decades,” said Austin.

One of those trends is water temperatures that are several degrees warmer than they were 40 years ago.

“We see more and more years where we see little to no open lake ice now,” said Austin.

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Researchers said that causes a number of problems for Superior’s ecosystem. Changing water temperatures can lead to fluctuating water levels, and impact whitefish eggs. If fish numbers decline something else could move in.

“One great concern that I think most Great Lakes scientists share is that this increase in water temperatures is going to make the lake more habitable to invasive species,” said Austin.

Zebra mussels have already changed ecosystems in other Great Lakes like Lake Eerie and Lake Michigan.

Austin said warmer temperatures can also be the cause for more Lake Superior storms in the future and potentially more algae blooms.

Every April, temperature gauges are placed in the lake to examine its overall health. While there are still cold years with substantial ice like 2009 or 2014, Austin is predicting future winters with less ice.

“I think what we’re going to see, if you want to go forward to 2050 or something like that, is that we are going to see a lot more years like 2012, where there’s basically no open lake ice,” said Austin.

In a sense, the personality of Lake Superior could change. Something researchers are preparing lake lovers for.

“Part of what defines who we are up here and how we interact with the landscape has to do with the fact that there is this huge lake right here. And the lake is not going to go away. But it is going to be a very different place, or could be a very different place than it is right now,” said Austin.

Austin blames the warmer temperatures on carbon dioxide emissions.

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He believes to slow down the changes in Lake Superior, we would need to cut back on carbon-based fuels in the future.