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Comment by Yizahi | Hacker News Reader

Oh, and while we are it, I have problem with correlating author's graphs of emissions with this graph of actual gas in the atmosphere:

https://keelingcurve.ucsd.edu/

You don't even need to be a big wig scientist to test this assumption. Open the graph on the big monitor and put a ruler or anything straight like a piece of paper to the median points corresponding to years 2000-2010. If emissions were "level" in the last decade then we should have 2010-2022 datapoints at most at the same line or even below the line. But in reality we see that the curve is raising up faster, meaning that the rate of emissions increased between years 10-22 compared to years 00-10, which contradicts author's graphs.

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It looks to me like the graphs agree - emissions were growing 2000-2010, so the average emissions during that period (which roughly correspond to the gradient you're measuring with a straight edge) are lower than those from 2010 onwards, even if yearly emissions stayed constant after 2010.

Yes, to put it simply, the rate of emissions stopped increasing but we are still emitting what we were in 2010 (plus a bit) so the keeling curve goes straight instead of continuing to subtly bend upwards.

If you take the emissions from 2000 to 2010, the total is less than from 2010 to 2020. [1] Hence the keeling curve of concentration should be steeper in 2010 to 2020. [2] That indeed is the case.

1: https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_pr...

2: https://keelingcurve.ucsd.edu/

Maybe I'm making some math mistake here, please correct me then. But I though that if a rate of addition is constant (horizontal graph), then the graph representing the sum total should be rising but linear. If the rate is negative, then the total graph would curve down. If the rate of addition is positive, then the total graph would curve up. And it's the last scenario which we see on the Keeling curve. Graph is curving up in the past decade, therefore rate of addition is increasing. No?

You're right except for the timescale of the claim that the graph is curving up in the past decade. Your observations show the graph curving upwards over the past 2 decades, during which we all agree that CO2 emissions were rising.

You're correct in general but you need to be more specific with the years if you think there's a discrepancy. One would assume that there's some time delay from mixing and some other sources of change. But I think there shouldn't be any if smoothed?

Easiest visually would be to integrate the emissions and compare it to the keeling curve, or differentiate the keeling curve and compare it to the emissions.

It's very hard to argue without numerical data, but the graph on the Wikipedia version of the graph seems to increase linearly to my eyes: https://en.wikipedia.org/wiki/Keeling_Curve (Edit: No, I can see what you mean; the graph is steeper from 2010–2020 than from 2000–2010.)

(To anyone a bit confused, the Keeling graph is the cumulative amount of CO2 in the atmosphere, so emissions are the first derivative of this graph.)

> ... so emissions are the first derivative of this graph

Not exactly. There is a net sink of emissions every year into the land & ocean, so d(CO2)/dt = emissions minus the net sinks, roughly. See the graph on CO2 partitioning [0]. A lot of research goes into whether these sinks continue at their current rate of removal.

[0] https://en.wikipedia.org/wiki/Atmospheric_carbon_cycle#Anthr...

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