Nima Rinji Sherpa’s ears are still tinged black from wind chill, an occupational hazard of climbing to heights where humans struggle to breathe and where the weather can turn deadly in an instant.Video above: Breast cancer survivor climbs Vermont’s highest peak while raising awareness for a cureThis month, Nima became the youngest person to summit all 14 of the world’s highest peaks, but the 18-year-old Nepalese mountaineer is already getting ready for his next big feat.Speaking to CNN via video call from the Nepali capital Kathmandu last week, Nima said he’s taking a couple of weeks to rest before preparing to climb the world’s eighth-highest mountain, Manaslu, with Italian mountaineer Simone Moro, in winter, alpine-style.“That means we’re climbing an 8,000-meter mountain in winter … There’s no fixed ropes for us, there’s no (supplemental) oxygen for us, there is no support for us. So, it’s like pure human endurance,” Nima said. …