4 ms·
One thing that bugs me is they measure CO2 levels in ppm instead of moles/m^3 (or whatever would be appropriate). Why is the denominator assumed constant? Why c
by nonbel 7y ago
One thing that bugs me is they measure CO2 levels in ppm instead of moles/m^3 (or whatever would be appropriate). Why is the denominator assumed constant? Why can't nitrogen, oxygen, argon, water vapor, etc be changing too?
In fact people have been extracting N2 from the atmosphere at scale for ~120 years: https://en.wikipedia.org/wiki/Haber_process https://en.wikipedia.org/wiki/Haber_process
And apparently O2 has been depleting as well: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5138252/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5138252/
We are at the point where gradeschoolers are questioning why the tables of atmospheric constituents don't add up to 100%:
>Two recent reliable sources cited here have total atmospheric compositions, including trace molecules, that exceed 100%. They are Allen's Astrophysical Quantities[5] (2000, 100.001241343%) and CRC Handbook of Chemistry and Physics[4] (2016–2017, 100.004667%), which cites Allen's Astrophysical Quantities. Both are used as references in this article. Both exceed 100% because their CO2 values were increased to 345 ppmv, without changing their other constituents to compensate. This is made worse by the April 2019 CO
2 value, which is 413.32 ppmv.
https://en.wikipedia.org/wiki/Atmosphere_of_Earth#cite_note-total%-8 https://en.wikipedia.org/wiki/Atmosphere_of_Earth#cite_note-...
- gregallan 7y agoIf you're saying that moles/m^3 of CO2 might be constant while pmm of CO2 is increasing, that implies that atmospheric pressure at sea level is dropping. And it isn't.
- rabidrat 7y agoThe temperature is increasing, though...
- yongjik 7y ago"Atmospheric pressure" is basically "total mass of air on top of us, per surface area". So it doesn't (directly) depend on temperature. Edit: Sorry, should be "total weight of air". My physics is rusty.
- nonbel 7y agoIf you took the same mass of air and put it in two tropospheres, one is 2 km high and the other 20 km high. Would there be the same surface pressure?
- yongjik 7y agoYou cannot put air at 2 km and then at 20 km high! Of course the second layer will just flow down until it's supported by the first layer, which is in turn supported by the ground. So your question doesn't really make physical sense.
- nonbel 7y agoI'm not saying it is constant. Where do you see that? Also, who says the pressure isn't dropping? Can that even be measured to detect such a small difference? And the volume and/or temperature of the troposphere could change instead. Finally, what about water vapor compensating?