In a wing of the Mendenhall Glacier Visitors Center a small crowd of onlookers is watching a debate between a man and an employee. The tourist is wearing a floppy hat and red shirt. And he’s leaning on a silver tipped cane as he listens — waiting for a chance to respond.About 80 percent of the people who come to the Mendenhall Glacier in the summer are tourists. (Photo by Elizabeth Jenkins, KTOO – Juneau)Download AudioKat Pratt is a ranger and interpreter.She was delivering talking points on sea level rise when the man — who didn’t want to give his name — challenged her. He thinks rising temperatures are cyclical. Not caused by people. And the climate change scientists are paid off by environmental groups.It goes on like this for about 15 minutes. Until they move onto something they both agree on: the glacier looks blue.Pratt seems unfazed.“I get it about once a day usually and some of them get more confrontational,” she said. Maybe some not educated as that last gentleman’s, and there’s a lot to learn.”She said it encourages her to do more research. And she learns how to talk to visitors from different backgrounds. Many have never seen a glacier before and haven’t been confronted with the effects of climate change. Aside, from say, experiencing a hot summer.“It became our central topic really just in the last few years,” said John Neary, director of the glacier’s visitor center.Neary is not afraid to admit he is on a mission. He wants the more than 500,000 people who visit the glacier each year to know that it’s rapidly retreating, due to climate change. The 18 interpreters who work for him are prepared to talk about it.He says, initially not everyone was game.“There was resistance and I think people viewed it as a negative thing,” he said., “And uh, you know people on vacation. They don’t want to hear about negative things. They want to think about positive [things] watch the whales, see the eagles. That sort of thing. I get that. That’s understandable.”But he says it’s all connected. Compounds from glacial silt wash down and feed the plankton that whales and other species depend on. Salmon spawn in nearby waters.In the past 30 years, Neary’s noticed an extreme visible difference in the glacier. He started at the forest service around that time. And at first, for him, Mendenhall wasn’t a big deal.“It didn’t seem very special to me to be honest,” Neary said. “It was just a glacier … You appreciate things are they become diminished in your life, you look at them differently when they are disappearing.”Now, Neary uses that when talking to visitors. He tells them about the time he was out hiking on a steep trail beside the glacier and his dog fell 90 feet onto the ice. Don’t worry, the dog survived.“But the story comes back to me when I go back out there and realize that spot which I climbed is now more than a half mile away,” he said. “And there’s no glacier, there’s dense alder thicket there. So there’s big changes.”And to address those changes, Neary wants to make changes to the visitor’s center, too. He wants the building to be LEED certified in the next few years. That means it will be energy efficient and produce less greenhouse gas.This approach has captured the attention of other countries. 11 delegates from Norway are visiting in June. Neary says they’re interested in seeing what the visitor center is doing and also sharing ideas. Chilean park officials are planning a trip in the fall.Neary wonders if parks around the world are trying to figure out what their role should be when it comes to climate change.“I think we are one in a million in the setting that we have,” Neary said. “But I’d like to think that the conversation is happening everywhere.”(Would you like to shake hands with the glacier?) Inside the visitor center, an interpreter lures a crowd over to touch a slick hunk of glacial ice. People stop to take selfies with it and snap pictures.(Would you like to see some photos of the glacier in the past?) The photos start in the 1950s and show the progression of how much the glacier has changed.(You can’t replace it right? No, we can’t.) Anna Laing – one of the people who watched the presentation – traveled a long way to be here.“We’re from Glasgow, Scotland,” she said.She says being on vacation, she had no idea she’d learn so much about climate change.“It’s just a statement that’s just out there, normally,” she said. “And it doesn’t really mean much to you until you really see the physical evidence of it. Especially, since we’re able to touch the glacier there and know what we’re losing.”Some scientists say the Mendenhall Glacier won’t be visible from the visitor center by the end of this century. John Neary hopes tourists have that in mind when they return back home.