I was trying to find a profile of how CO2 is distributed with altitude, and I didn't find that.
I did find https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_atmosphere which indicates that CO2 levels have been relatively low for millenia, but if you go back far enough, they have been much, much higher than what we're seeing now. But it did have a link to a page with an estimate of carbon in the atmosphere of 720 gigatons: https://en.wikipedia.org/wiki/Atmospheric_carbon_cycle CO2 has a molecular weight of 44g/mol and O2 has a molecular weight of 32g/mol, and C has a molecular weight of 12g/mol. If "carbon" here was C rather than CO2, that would mean that the change in mass of CO2 since 1960 would be about 80*44*7.2e11%12*410 5.15122e11 But running through your calculations with the change in mass contributed by CO2 being 15.049 g/mol (44.01-28.96) gives a total mass of CO2 change since 1960 of 2.162e11 and I have reason to believe that that number is too high.. So if that 720 gigaton number is right, it probably represents a weight of CO2 and not a weight of bare C. This gives weight of CO2 change in atmosphere somewhere near 80*7.2e11%410 1.40488e11 Which better fits what I would expect after thinking about the base numbers you presented. (Assuming the 720 number was correct - it's very easy to make mistakes and people tend to be sloppy with labels -- assuming that everyone knows what they were thinking.) Thanks, -- Raul On Fri, Jun 7, 2019 at 5:25 PM Raul Miller <[email protected]> wrote: > > Ok... working through the numbers. > > If 28.96 is the current molecular weight of air, then there is no > increase from CO2 - instead, you would subtract from that weight to > find the molecular weight of air in 1960. > > If currently, CO2 represents 410ppm of air, then I would expect that > the total molecular weight of air has a g/mol contribution of > 44*410%1e6 > 0.01804 > > Note however that when I read up on the molecular weight of air, > people make pains to mention that their numbers represent the dry > weight of air, and sometimes talk about how this changes due to H2O. > It would probably be worth understanding the details they provide as > there's some subtle things going on here. > > Anyways, we don't just add the weight of the CO2 molecules - they are, > roughly speaking, replacing other averaged molecules. So it's roughly > the difference between the previous average weight and the CO2 average > weight that's going to give us the increase in weight. > > So the change in atmospheric molecular weight would be less than the > values currently listed on {4} and {5}. Still... your lines {4} and > {5} look to be roughly within an order of magnitude or two for the > change in average molecular atmosphere weight due to increased CO2 > since 1960. > > But then we get to the mass of the atmosphere, and I think you've > oversimplified: https://en.wikipedia.org/wiki/Atmosphere_of_Earth > describes the structure of the atmosphere. Since CO2 is heavier than > some other components (oxygen, nitrogen), it's not going to rise as > much as the lighter gasses. Still, we could use the number on line > {7} as an upper bound... > > I don't understand your lines {8} and {9} so I'll stop here. > > Thanks, > > -- > Raul > > On Fri, Jun 7, 2019 at 12:18 PM Ian Clark <[email protected]> wrote: > > > > The addons math/tabula and its parent addons math/cal and math/uu have been > > largely rewritten and are now far stabler than they were. > > > > The main way to get to grips with TABULA is via studying the built-in > > t-tables ("TABULA-tables") SAMPLE0--SAMPLE9… > > > > https://code.jsoftware.com/wiki/TABULA/samples > > > > The last one, SAMPLE9, is particularly noteworthy. See this page for > > details… > > > > https://code.jsoftware.com/wiki/TABULA/samples/cost_to_capture_atmospheric_CO2 > > > > Atmospheric CO2 concentration has been rising steadily since 1960, when it > > first began to be measured regularly at Mauna Loa, HI. At that time it > > stood at <320 ppm (parts-per-million). Now it stands at >400 ppm, an > > increase of over 80 ppm. > > > > This observed level of atmospheric carbon is gaining wider acceptance as > > having a damaging effect on the world's climate. Whether it does or not, a > > British Columbia-based firm called Carbon Engineering has built a plant to > > capture CO2 from the atmosphere, at a cost of <$100 per metric ton (100 > > USD/t). They have attracted $68 million investments from Chevron, > > Occidental and coal giant BHP. > > > > https://www.bbc.co.uk/news/science-environment-47638586 > > > > I don't want to take sides over this. Nor to invite the taking of sides in > > this thread. Rather it's my aim to develop tools to help the rest of us > > explore the figures for ourselves, whatever side we're on. Relying on > > specialists to do the calculations is simply to promote a new world > > religion, with applied mathematicians as its priesthood. > > > > So I thought I'd take Carbon Engineering's current price and use TABULA to > > calculate what it would cost to restore atmospheric concentration to 1960 > > levels. > > > > The cost comes out rather high: around 57 times the projected USA budget > > deficit for FY2020, would you believe? > > > > This raises vital questions for me: > > > > ++ are the input figures reliable? I used Google to track them down, but > > have I copied them over correctly? > > > > ++ is TABULA doing it right? I'm terrified of orders-of-magnitude errors, > > which can so easily arise with a misplaced prefix 'k' (kilo-) or 'G' > > (giga-). > > > > Would anyone fancy checking my calculations? > > > > Ian Clark > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
