The summit of Mount Everest is a deadly place. There is only one-third of the amount of oxygen available to humans at sea level. The wind and the cold are life-threatening. Many summiteers keep their oxygen masks on during their few minutes on top of the highest mountain in the world. But how long could they survive if they took the mask off?
You can survive on the summit of Everest for at least 21 hours. Babu Chiri Sherpa spent 21 hours on the summit of Mount Everest without supplementary oxygen in May 1999. His record still stands.
Babu Chiri Sherpa held another record: the fastest ascent of Everest in just 16 hours and 56 minutes, so he was supremely fit and acclimatised. Sadly he was killed on April 29, 2001 when he fell down a crevasse near Camp 2 at 6,500 metres. But how long can average humans survive on the top of the world? And could a permanent settlement be established there, like a camp on Mars?
The answers might surprise you.
How Long Do Climbers Spend on The Summit of Everest?
In recent years, with so many people attempting to reach the summit on the same few days, there is pressure to snatch just a few moments on the top of Mount Everest. Just time to gaze at the stupendous view, take a couple of photographs and pose for the obligatory summit shot. Then there are shouts from other climbers to move out of the way.
Ten minutes on the top of Mount Everest is about average.
Sometimes climbers are obliged to remain on the summit. On such was my friend the guide Mark Whetu, who in 1994 stayed near the summit for 13 hours with his client Michael Rheinberger until he could no longer help him.
On May 26, 1994 Whetu, Rheinberger, and Dave Staeheli left for the summit from the top camp on the North side of Everest. Rheinburger had tried to climb Mount Everest no less than seven times before, a fact that now might be seen as a warning.
They had good weather at first but climbed dangerously slowly. Staeheli was concerned by how late they were getting and turned back from the Second Step at midday. Whetu had summitted in 1991 and was a powerful climber, but Rheiburger was far too slow. They finally reached the summit at 7.18 p.m, which we now know is fatally late in the day.
Retreating just 20 metres from the summit, the two climbers spent a horrific night sitting on the mountain side in an open bivouac in the thin air and freezing wind. By the morning Rheinburger was delirious, blind and unable to walk.
For eleven hours Mark Whetu virtually carried his client 900 feet down the mountain to just below the Second Step. Increasing winds meant that a rescue party sent up by expedition leader Eric Simonson were unable to reach the pair.
Whetu’s feet became severely frostbitten. Rheinburger was clearly beyond saving, a second death was futile, and so very reluctantly Whetu was pursuaded to leave Rheinburger to his fate (source: American Alpine Club). Whetu did his very best, and should be commended.
What can we deduce from this? Together with evidence from the 1996 Mount Everest disaster it seems that an acclimatised average Everest climber might survive around 12 hours at the summit, some perhaps longer, some less than this.
Certainly if an unacclimatised human was dropped on the summit by helicopter (see: Can Helicopters Fly to the Top of Mount Everest?) they would lose consciousness and die within minutes.
In October 1993 I was able to remove my oxygen mask on the summit for half an hour or so and look at the view. I felt OK, but while climbing down I felt breathless.
What is the altitude at which continuous human habitation is possible? Oddly enough we know this from evidence in Peru. No less than 50,000 people live in La Rinconada, a gold mining town in Southern Peru at around 5,100 meters, or three miles high (source: earthobservatory)
There was even a miner’s camp at 5300 m for several years (source: liebertpub), and humans have survived for two years at 5,950 m (19,520 ft, 475 millibars of atmospheric pressure), which is the highest recorded permanently tolerable altitude.
Continuous human habitation would involve giving birth to viable babies, and I was once aware of a live birth in a yak-herders hut in the settlement of Pheriche near Mount Everest at 4,371 m (14,340 ft). The medic attending the delivery of the baby told me that was about the altitude limit.
So a permanent human settlement on the summit of Mount Everest is unlikely for now!