Sure, you’ve thought about glaciers melting and oceans rising, wildfires in the West, bigger and nastier storms along the East Coast, hurricanes in the Caribbean, and a million other complications for adventure in the coming years as the climate continues to warm, but have you also thought about the vagaries of chemistry affecting how the adventure world will be shaped in the near future?
Even if you have, there’s some interesting work being done about atmospheric pressure changing as the planet warms, and what that means for oxygen saturation levels at various elevations.
A new study, available for free (refreshingly) at iScience shows how oxygen levels change at Everest’s highest elevation depending on air pressure, and with warmer summers the air pressure will be higher, meaning more oxygen should be available near the summit. The increase in oxygen is expected to be “physiologically relevant” for climbers attempting the world’s highest peak.
Interestingly, as the paper lays out the background for the study, the authors explain that Everest is actually slightly more oxygen-rich, even at its peak, than would be expected simply by examining the elevation. You can actually, well, typically, anyway, infer the amount of oxygen available at a given elevation by examining the air pressure/elevation relationship. Everest’s air pressure is higher than would be expected, which, according to the study, is the only explanation for why it’s at all possible to ascend to the peak without oxygen, something long assumed impossible until Reinhold Messner and Peter Habeler pulled it off in May, 1978.
The same is true for all other 8,000-meter peaks on the planet, simply because they lie in the subtropical zone, and have access to slightly warmer air. If Everest were in, say, the Arctic, it’s likely oxygen would always be required.
For instance, in the winter, when temperatures and air pressures drop on Everest, it’s likely that the oxygen level is, at that point, at the absolute floor, or more probably, beneath that of what even the fittest human could tolerate.
Which brings us to the new information the study presents.
A warmer atmosphere means more pressure, which means more oxygen. As pressure increases, oxygen molecules pack tightly together, increasing the amount of oxygen in a given mix of gasses, like our atmosphere. If global temperatures increase at the 2°C limit outlined in the Paris Climate Agreement, that could directly translate to about a 5% VO2 max increase for the climber.
Because elevation is felt relatively as a matter of oxygen saturation, this is effectively like reducing the height of Everest’s peak by roughly 118 meters, or, close to 400 feet. Not necessarily a game changer, but absolutely noticeable and significant.
Further, the study points out, if the climate warms to something like 7°C, which is within the realm of possibility, it would effectively make the oxygen saturation on Everest in the winter high enough to climb without supplemental oxygen.
Interestingly, it also points out that because air pressure changes near the summit of Everest can fluctuate according to temperature, there are times at which the apparent elevation of the peak can swing up to 750 meters, again, because we feel elevation as a function of how much oxygen is available in the air. This could explain why some elite climbers are able to push through without supplemental oxygen, and some aren’t. It may be a stroke of atmospheric chance.
Regardless, the study is fascinating, and a rare, readable look at vagaries of atmospheric chemistry at the world’s highest peak, and one that may have an impact on how climbers prepare for, and think about, such a monumental effort.
Read the study, here.
Photo: Ben Gao/Unsplash