How do sea levels impact air pressure on Mount Everest?
April 11, 2014 7:42 AM Subscribe
As the sea level rises and falls, how does that impact air pressure on Mount Everest?
Climbers on Mount Everest typically use bottled oxygen because of the low air pressure that reduces the amount of oxygen in the bloodstream. If the oceans rose, would it become easier to oxygenate your blood at high altitudes? And if the sea level dipped, would it become harder?
These are the things that keep me up until 3am, staring at a dark ceiling and mustering my inconceivably small amount of meteorological and climatological knowledge.
Climbers on Mount Everest typically use bottled oxygen because of the low air pressure that reduces the amount of oxygen in the bloodstream. If the oceans rose, would it become easier to oxygenate your blood at high altitudes? And if the sea level dipped, would it become harder?
These are the things that keep me up until 3am, staring at a dark ceiling and mustering my inconceivably small amount of meteorological and climatological knowledge.
Everest is 29,000 feet tall. The kinds of rise in sea level we're facing with climate change are in the single-digit range. Six feet of ocean rise, for example, is plenty to cause massive problems for human settlements which tend to be located right by major bodies of water, but the mountains won't even notice it.
posted by Tomorrowful at 7:49 AM on April 11, 2014 [4 favorites]
posted by Tomorrowful at 7:49 AM on April 11, 2014 [4 favorites]
Response by poster: As a thought experiment, lets say that all of the antarctic ice melted and the oceans rose by twenty meters. What impact would that have on the density of the atmosphere (no matter how small) with the interaction of earth's gravity?
posted by burnfirewalls at 8:20 AM on April 11, 2014
posted by burnfirewalls at 8:20 AM on April 11, 2014
You say "no matter how small," but the thing is, you're talking about changes that would be absolutely immeasurably tiny. Twenty meters is nothing compared to the height of Everest or the atmosphere.
As for gravity, it changes nothing. Gravity has nothing to do with density - it's about how much mass there is, not how it's arranged. You could instantly crush the Earth into a ball one foot on a side, and the moon's orbit around it would be totally unchanged.
posted by Tomorrowful at 8:32 AM on April 11, 2014
As for gravity, it changes nothing. Gravity has nothing to do with density - it's about how much mass there is, not how it's arranged. You could instantly crush the Earth into a ball one foot on a side, and the moon's orbit around it would be totally unchanged.
posted by Tomorrowful at 8:32 AM on April 11, 2014
I would argue that you would actually reduce the air pressure at the top of Everest with sea level rise.
The biggest factor in sea level rise is due to moving ice from the continents to the oceans. If you just moved all of the ice from the continents to the oceans as floating icebergs, sea level would rise as expected, but it wouldn't change the air pressure at all because the earth would have exactly the same volume as before. You've just moved ice from one place to another. So to a first approximation, sea level rise does nothing to air pressure. The volume of the earth which displaces air is unchanged.
But if you then melt the ice, it does reduce its volume by about 9%. This reduces by a tiny amount the average diameter of the earth that displaces the air so there will be less air at 29,000 feet. The change is tiny because the volume of ice is small compared to the total volume of the earth.
This ignores the counteracting effect of expansion of water due to a temperature increase, but if you consider melting of all of the ice, the decrease in ice volume is much bigger than the increase due to water expansion.
posted by JackFlash at 9:46 AM on April 11, 2014 [4 favorites]
The biggest factor in sea level rise is due to moving ice from the continents to the oceans. If you just moved all of the ice from the continents to the oceans as floating icebergs, sea level would rise as expected, but it wouldn't change the air pressure at all because the earth would have exactly the same volume as before. You've just moved ice from one place to another. So to a first approximation, sea level rise does nothing to air pressure. The volume of the earth which displaces air is unchanged.
But if you then melt the ice, it does reduce its volume by about 9%. This reduces by a tiny amount the average diameter of the earth that displaces the air so there will be less air at 29,000 feet. The change is tiny because the volume of ice is small compared to the total volume of the earth.
This ignores the counteracting effect of expansion of water due to a temperature increase, but if you consider melting of all of the ice, the decrease in ice volume is much bigger than the increase due to water expansion.
posted by JackFlash at 9:46 AM on April 11, 2014 [4 favorites]
Best answer: I think the OP is asking, wouldn't the rise in sea level "push up" (displace) the air, thereby increasing the amount of air above you? The OP is not asking about gravity at all, and of course it wouldn't change gravity.
OP, to answer you question, I would think not. That ice is already "pushing up" the air where ever it is now. The Earth's volume isn't changing.
Actually, it might even decrease since water is one of the few compounds that becomes less voluminous when going from solid to liquid, (because of ice's crystal structure). In the other direction, since it would be warmer it would gain some volume there, but the former effect is more powerful, which is why frost/thaw creates cracks in materials over time.
Twenty meters is nothing compared to the height of Everest or the atmosphere.
The tinest speck of dust in the most distant part of universe has a gravitational effect on you. The OP isn't asking about how measurable it is, just if it's there.
posted by spaltavian at 9:49 AM on April 11, 2014 [1 favorite]
OP, to answer you question, I would think not. That ice is already "pushing up" the air where ever it is now. The Earth's volume isn't changing.
Actually, it might even decrease since water is one of the few compounds that becomes less voluminous when going from solid to liquid, (because of ice's crystal structure). In the other direction, since it would be warmer it would gain some volume there, but the former effect is more powerful, which is why frost/thaw creates cracks in materials over time.
Twenty meters is nothing compared to the height of Everest or the atmosphere.
The tinest speck of dust in the most distant part of universe has a gravitational effect on you. The OP isn't asking about how measurable it is, just if it's there.
posted by spaltavian at 9:49 AM on April 11, 2014 [1 favorite]
But, another factor is that melting the ice caps is going to put more water vapor into the air, (a) because a lot of water is unlocked from its previously frozen state, and (b) because there going to be more open water from which evaporation occurs. An atmosphere that is more humid because of all this evaporation is going to be denser, on average, which would tend to increase its pressure from top to bottom.
posted by beagle at 9:52 AM on April 11, 2014 [1 favorite]
posted by beagle at 9:52 AM on April 11, 2014 [1 favorite]
Good point, beagle.
posted by spaltavian at 9:53 AM on April 11, 2014
posted by spaltavian at 9:53 AM on April 11, 2014
The addition of water vapor doesn't increase air density. It reduces it. That is because a molecule of H2O weighs less than a molecule of N2 or O2.
posted by JackFlash at 9:56 AM on April 11, 2014
posted by JackFlash at 9:56 AM on April 11, 2014
Normal changes in weather cause the atmospheric pressure to change by up to about 3%, approximately the same as a 1000 foot change in elevation.
A change of a hundred feet in sea level (huge) would therefore change the pressure by less than that already caused by weather.
posted by phliar at 10:28 AM on April 11, 2014
A change of a hundred feet in sea level (huge) would therefore change the pressure by less than that already caused by weather.
posted by phliar at 10:28 AM on April 11, 2014
The addition of water vapor doesn't increase air density. It reduces it. That is because a molecule of H2O weighs less than a molecule of N2 or O2.
OK, but the H2O is not actually replacing any of the N2, O2 or other gases in the atmosphere. So it is going to add to the total mass of the atmosphere. Wouldn't adding mass to the atmosphere tend to increase the pressure at all altitudes?
posted by beagle at 11:28 AM on April 11, 2014
OK, but the H2O is not actually replacing any of the N2, O2 or other gases in the atmosphere. So it is going to add to the total mass of the atmosphere. Wouldn't adding mass to the atmosphere tend to increase the pressure at all altitudes?
posted by beagle at 11:28 AM on April 11, 2014
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posted by i_am_a_fiesta at 7:46 AM on April 11, 2014