BY KAREN BOSSICK

Robert Swan knows what it's like to have ice inside his underpants.

He has trekked in minus-87 degrees Fahrenheit as he trekked 900 miles to the South Pole and 700 miles to the North Pole, becoming what he says is "the first person in history stupid enough to walk to both Poles."

"After 900 miles I had lost 69 pounds and I hadn't had a shower in a year but I made it. And, while walking to both poles was completely pointless, we were proud of what we had achieved,” he told a crowd at Ketchum’s Limelight Hotel this past week.

Beyond pride, his accomplishments also gave Swan credibility that has come in handy as he's pled the case of the environment before the world.

He did that this past week at the third annual Sun Valley Forum, which brought more than 200 innovators from government, business, nonprofits, investment and academia to Sun Valley for four days to share strategies, ignite partnerships and promote brainstorming about some of the world's pressing issues.

Inspired as a boy by Antarctic explorers like Robert F. Scott and Roald Amundsen, the English-born Swan bought a $5 million ship with the help of ocean explorer Jacque Cousteau to travel “3,000 miles from civilization” to the frozen continent of Antarctica.

He waved goodbye to the ship, knowing he’d be cut off from the rest of the world for the next year. Then, after wintering at the Jack Hayward base, he and two others set off on an 80-day walk to the South Pole, carrying everything on 350-pound sleds.

They crossed 6,000 crevasses, or what Swan called “death traps.”

“We carried no ropes, no ladders because you can’t eat them,” he said.

Antarctica is more of a desert than the Sahara, Swan said. The biggest danger is not hunger but dehydration.

They navigated using the sun—their goal, the South Pole Station in the center of an area the size of the United States.

“Everybody said we’d die. If we failed, we died. There was no backup. If we made one mistake, we arrived at nothing,” he said.

They arrived 300 yards off course, only to be greeted with the news that the ship sent to pick them up had sunk five minutes before, crushed by ice.

Swan returned three years later to remove all traces of his expedition—one of the conditions Cousteau had asked for in exchange for helping him.

"The greatest thing any of you can do is give someone credibility when they're trying to get something done," he said, of Cousteau’s help.

Three years after reaching the South Pole, Swan assembled a team of eight people from seven nations to go to the North Pole.  

It was an arduous expedition involving 56 nights in a tent in temperatures as low as minus-72 degrees.

The explorers almost drowned when the frozen Arctic Ocean melted beneath their feet 642 miles from land.

“It melted four months before it ever had," said Swan, noting that no one was even talking about climate change at that time. "I told myself, 'I'm a damn good survivor—l’m really good at staying alive.’ And I realized on that day we were going to die.

“We didn't have a helicopter hovering above like they do on the survival programs on Discovery. We didn't have a Russian submarine out there. We were eight people and no one knew where we were."

Swan ordered 14-hour days with one hour of sleep in between. An African-American explorer from Harlem had his heel disconnect from his foot. But he plodded on.

"Where we were, you had 24 hours to recover if you broke an ankle or a leg. Then you were left to die," said Swan. "He kept walking on that foot—he had to. Then the wind changed and we got there."

“I did not choose my best friends for these expeditions,” he added. “I chose people who would challenge me, push me. We told each other the truth.”

Swan found a new calling amidst the melting of the Arctic ice and the conditions he experienced in Antarctica, where his eyes changed color and his face became painfully blistered from walking under the hole in the ozone. He began throwing his weight behind environmental causes.

If you want to make a difference in the world, you need to be relevant, he told those attending the forum.

“It’s easy to think we’re all relevant but sometimes we get stuck. You need to check to see if you’re still relevant.”

Swan organized a South Pole Challenge that took 35 youth from 25 nations to Antarctica to remove 1,500 tons of waste left behind by researchers to Uruguay where it was recycled. The native penguins applauded his efforts, reclaiming their beach for the first time in 47 years.

And he began taking a 67-foot racing yacht with sails made of recycled plastic bottles around the world, to inspire young people about renewable energy. He named the boat “2041” the year the Madrid Protocol comes up for debate offering protection for Antarctica.

In November 2017 he plans to make one last expedition to the South Pole with his 23-year-old son Barney on the South Pole Energy Challenge. The two will ski on a 600-mile journey surviving solely on renewable energy, such as ice melting technology that NASA hopes to use on Mars one day.

“This is the first time that’s ever been done—we want to show the world that if we can survive on renewable energy in the most inhospitable place on earth, we can do so anywhere,” he said.

One month after their return—in February 2018—father and son will take part in the Climate Force: Antarctica expedition open to the public that will use Antarctica as a platform to protect the world by creating a more sustainable, clean energy future.

“Antarctica is owned by all of us. It represents our past and future within its ice and, if the ice keeps melting at its current rate, the rising sea levels will have disastrous effects worldwide,” Swan said. “It’s untouched, and we must do everything we can to preserve it.”

Swan said he is not looking forward to "a bit more walking."

But, he said, what he sees in the Antarctica is terrifying, what with 64-degree temperatures being recorded and the Larsen Sea Ice Shelf the size of England breaking off (part of the iceberg twice the size of Luxembourg was found to have split off Wednesday morning.)

"I sure hate bloody walking," he quipped during his presentation at the Sun Valley Forum. “But the greatest threat to our planet is the belief someone else will save it.”