“I am mostly in a mode of decompression,” he says. “It was a trip in a number of ways. It’s very hard to discuss because a lot of what I experienced out there is entirely ineffable. Most of us had never been to the Arctic before, or done anything that demanding. We would trek 10km a day and we had to carry a lot of heavy technical equipment. It was demoralising at times. It was the hardest, most extreme and probably the most worthwhile thing I’ve ever done.”
On the ten-day trip, the 20-year-old star of We Need To Talk About Kevin and The Perks Of Being A Wallflower was part of a 16-strong team tasked with lowering a capsule – containing almost three million signatures, including those of Cameron Diaz, Sir Paul McCartney, One Direction and Sir Richard Branson – and planting a flag on the seabed as part of an international Greenpeace campaign to protect the area from oil drilling and climate change.
While they were successful in their mission, Miller has been left with a lack of feeling in his fingers and some of his toes, an “accumulative effect” from the bitterly cold temperatures, which dropped to minus 45 degrees at times.
“Certainly, the toughest thing is the cold,” he admits. “It is an inhospitable environment because it is too cold for a human being to exist there. You remove your mittens for 30 seconds and you experience the worst pain you have ever felt in your life in your fingers.
“I don’t have full feeling in three fingers and my toes and I am a little worried, but I’m hopeful my circulation and nerves will return. I’m really grateful and happy I still have all my digits. That’s a profound blessing.”
But the physical pain was worth it, he says, adding: “I would have even given more.”
He is currently fighting to get his body back into healthy mode. “I caught a disease called North Pole-io,” he jokes. “The humour got more tasteless and less and less funny as we trekked on. Any pun will do.
“My body wasn’t ready for those conditions and smoking probably doesn’t help. I quit for two months during training, and then the second I got to Svalbard (in northern Norway), I thought immediately, ‘It’s cold, I want a cigarette’. It was the best I’ve ever smoked.”
Miller survived on an unappetising diet of frozen butter, cheese cubes and salami throughout the trip.
“I was raised as an organic granola child and my body could not handle the freeze-dried food that was our official food source. So on day two I stopped eating it, which left me with the option of trail mix, frozen sticks of butter, chocolate, frozen salami and frozen cheese. So I went in hard on the butter. That was what I subsisted on the whole time,” he says, laughing again.
“Due to our limited amount of fuel, I would melt the butter, salami and cheese in the same pan and consume it straight from there. I’d call it ‘Arctic fat sludge’.”
He often dreamt of eating fresh vegetables. “Someone told me you dream about your loved ones initially on an expedition like this, but then you dream about food you’re going to eat if you survive,” he recalls.
“I spent a lot of time thinking about radishes, how delicious they are and how badly I wanted a fresh radish to crunch into. I’m on a devout vegetable-eating binge now in an attempt to restore my natural palate.”
Aside from the food, Team Aurora, as they were known, had to trek each day with their heavy sledges to reach camps before they arrived at their final destination. Miller was joined by three other youth ambassadors – Renny Bijoux from the Seychelles, Josefina Skerk from the indigenous Sami community in Sweden and Canadian activist Kiera Kolson.
“One of the greatest challenges is you are standing on a frozen ocean and you’re on a piece of ice that can drift in any direction,” Miller says.
“We had the misfortune of having a rapid drift southwards so for most of our trekking time we were struggling to hold our geographic position. We would trek 10km a day, and then find we had moved backwards two kilometres. That was tough. But even though we trekked for five days with no progress, we did another day and pushed as hard as we could.
“All our equipment malfunctioned because of the extreme cold. In the end, we were almost out of fuel, which would have meant certain death, and I almost fell off a pressure ridge at one point – they are scary.
“I was also acting like a fool and leaping across the hole we made for the pod, and I very nearly slipped in, which would have meant being trapped in the Arctic ocean under a metre layer of ice.”
He adds: “It was really important that we had such an incredibly loving group that was determined to keep smiling, even in harrowing circumstances.”
Miller, who says he would do it all again without a doubt, wanted to get involved because he is a “humanist”.
It is not the first time he has done something for the environment – in November he teamed up with hip-hop producer Sol Guy to help Native American tribes buy back a piece of land in south Dakota they consider sacred. The New Yorker has also been involved in anti-war and anti-globalisation protests, and the Occupy Wall Street movement in New York.
“I view environmentalism from a human perspective. I think babies are adorable and they have an inherent right to experience all the pleasure of life as we know it, and they should have an opportunity to have babies of their own,” he says.
“I embarked on this mission because I like to think of myself as a storyteller and I see humanity weaving one great story of our own survival. Right now, we’re telling the story of a lot of hubris and folly which usually, in conventional storytelling, precedes utter tragedy and catastrophe.”
While the capsule containing the signatures represents the number pledging their allegiance to a mass movement to save the Arctic, he hopes more people will be aware of the effects oil drilling has on nature and stop supporting companies which want to drill there.
“I think we can mitigate and reduce the effects of climate change on this planet. Three-quarters of the Arctic sea ice has gone since records began, from 1979 till now, and that is a direct result of human-caused climate change,” he explains.
“Inevitably, there will be further efforts to bring destruction into the Arctic and we, as a civilisation, have to be prepared to collectively raise our voices to stop that happening. It’s sheer madness and lunacy.”
Miller wants other celebrities to get involved. “I think a lot of artists feel very choked and incredibly frustrated with their ability to speak their minds or influence change, because we are employed by corporations which are part of larger umbrellas that are centrally involved in what is happening on our planet,” he says.
“It’s a privilege to make art on a mass-media scale and it’s very scary to put all of that at risk simply to get a message across. But in the context of this short lifetime we’re given, and what our actions could mean to the future, then it seems pretty obvious what we should do.
“Besides, what is there really to lose? Maybe it’s time some of these ‘heroes’ of modern mythology start acting like heroes. I encourage those veterans of this industry that know the power they hold to step forward and to do something courageous to make any effort to make a difference.”