The story inspired many when the now 24-year-old Hooper recalled fond memories of Gauntlett - who died in a climbing accident in 2009 - at a Royal Geographical Society lecture in Hong Kong.
Without much funding or sailing experience, the duo set off into the blizzards of northern Greenland in March 2007. They were eager to prove themselves and highlight the growing dangers of climate change.
That year had seen the Arctic's biggest ice melt on record. Ice sheets broke apart, creating open water that spanned several kilometres. Indigenous Inuit people used to hunt on dogsleds until late July each year, but they were struggling to get out in April. "It seemed that the 2,000-year-old tradition was coming to an end," Hooper says.
Swiftly they decided to go dog-sledding across the glaciers. Poorly prepared, they went the wrong way and came close to disaster.
As Gauntlett tried to fetch a lost glove, he fell through thin ice and knocked himself out. "He was blue, barely breathing and weak," Hooper recounts. "I was pretty scared. Luckily I dried and warmed him immediately, so he was able to recover over the week."
This frightening episode did not put them off. They carried on to New York by yacht and from there they began an 18,000km cycling trip to the tip of South America. They endured scorching temperatures of 48 degrees Celsius, rain that turned roads into rivers, and crossed dry, dusty deserts.
"The cycling was the physically hardest part of the trip," Hooper says. "But we always saw new things and met new people."
By the time they reached Panama - halfway through the trip - they were broke, with only US$5 between them. But they didn't lose heart. They gave talks in schools and sold signed T-shirts to raise funds to keep going.
Back on the road, their persistence was rewarded with the moonscapes of South America's Atacama Desert. "The sky turns white with stars at night," Hooper says. "South America is an incredible, beautiful, desolate and intriguing place."
The boys set aside their bicycles at Punta Arenas, Chile, in January 2008 to sail 14,500 kilometres to the South Geomagnetic Pole.
Two months behind schedule, they missed the calm season of the notoriously stormy southern seas. Waves 25 metres high, hurricane-force winds, white-outs and bitter cold awaited them. Once, a giant wave flipped their boat upside down and smashed their radar. They even had to dodge icebergs.
"Some of the situations were so scary ... we knew we were completely powerless," Hooper says. "But it was miraculous to see, at the end of the day, the most beautiful aurora australis - green curtains of light going from horizon to horizon."
The adventurers sailed through the South Geomagnetic Pole on April 24, 2008, and arrived in Sydney on May 9, 409 days after setting out. Their success was widely applauded and even earned them the National Geographic "Adventurers of the Year" award.
Hooper says: "I was amazed by the fact that despite starting without any money or skills, just the sheer power of having a dream, setting a goal and getting stuck into it, you can achieve feats that seem impossible."
Learn more at 180degrees.com