Challenges included temperatures of minus 40 degrees, deep snow and hard ice ridges. Over this inhospitable terrain, they towed a sled with the only provisions they would have throughout the journey. Weighing 165kg when they set out, the sled variously bogged in deep snow, then jammed on sastrugi, (sharp ridges of snow sculpted by wind). With some 10 years in planning, they had not expected the conditions to be so difficult. From 84 degrees south to 88 degrees, over about 440km the sastrugi was from ankle-high to more than three metres.

"We don't know of any other reports of sastrugi being so bad," Gareth Andrews said.

For about 30 days they travelled about 25km daily, increasing to 30km. As conditions worsened, this reduced to about 17km. By Christmas Day, 2022, feeling exhausted, they had a chat and did the maths and agreed their journey would have to end at the South Pole, not the Ross Ice Shelf.

"We had to reassess our goal," Dr Andrews said. "We had to reassess and reaffirm getting home safely to our families ... you have to be flexible with your outlook and approach."

Richard Stephenson quipped: "It is not an adventure if you know what is going to happen."

When left alone on the ice as their plane left, they wondered if this was really a good idea. They had been, then, probably the most isolated people in the world.

Dr Stephenson, born in England, moved to New Zealand in 2011 and lives in Dunedin.

Dr Andrews was born in Scotland and grew up in Cornwall. When aged 21 he moved to Australia. They met because, Richard said: "Gareth's sister is my partner."

Gareth is an anaesthetist and Richard an emergency physician. In their youth, both were also Scouts.

As ambassadors for Scouting, in 2022 they were reinvested as members of Scouts Australia by the Governor-General and chief scout of Australia, General David Hurley.

When planning their unsupported crossing of Antarctica, they had recognised the opportunity by working with Scouts Australia to do something really good with the expedition. To bring Antarctica, climate science and climate change into the lives of young people across the world.

Dr Stephenson said: "There are so many lessons that can be learned through this sort of expedition."

These lessons include mateship, leadership, resilience and determination. Dr Andrews said this was not limited to outdoor pursuits.

Dr Stephenson said the hardest part of their expedition was the overriding psychological aspect - missing family and knowing they would be missing Richard and Gareth. And managing the many hours of skiing when it was easy to ruminate. Listening to audio-books and podcasts helped.

"We didn't have a cross word between us for the two-and-a-half months we were out on the ice," Dr Andrews said, attributing this to the 10 years they had done adventures together.

"We know each other extremely well."

During their journey, they collected scientific data almost daily. This included ground-level meteorological data and sastrugi height measurements.

Of their expedition, Dr Andrews said: "It has given us something very special."

To young people, he said: "They need to find a thing that they are most passionate about and that they really enjoy doing. That they find that thing that really lights a spark and chase it and do whatever you can to achieve it with hard work and determination. It doesn't have to be extreme but it is important to find that thing you really love."

Richard said it was about setting goals and striving. What was hard was personal. It does not have to be an adventure but setting a goal and pushing yourself to achieve it.

Their next challenge? Dr Andrews said adventures with their families close to home. "But we have our eyes on the ice sheets in Patagonia. The land of great adventures, of storms and craggy peaks and also the opportunity to do more science and to bring back and share stories about the changing ice and the changing conditions in Patagonia," he said.