Atmospheric CO2 Levels Are Accelerating

I see atmospheric CO2 levels plotted vs year pretty regularly, but I realized that I don't recall seeing how much it actually changes each year so here's that...

It turns out that it's accelerating. That is, the change per year is going up each year. I hadn't realized that until now. Interestingly, methane (CH4) does not show the same trend:

Also maybe interestingly, human CO2 emissions are almost perfectly correlated with atmospheric CO2 level increases:

This is extremely simplistic and shouldn't be taken as proof of causation...I just realized I hadn't seen them plotted this way and figured I'd show it.

On that last one, I actually feel a bit dumb. There's no way it isn't noisier than that. There are so many things that cause spikes in atmospheric CO2 that are unrelated to the emissions so example is a massive forest fire. I feel like I'm missing something obvious that explains why a linear fit works so well there other than the implication that human emissions are solely responsible for the increase in atmospheric CO2. If anyone knows, please let me know in the comments. It feels too simple for it to just be 'we get an additional 1 ppm of atmospheric CO2 for every 14 Gt of CO2 that we emit'.

If that relationship is a thing though, it allows for something cool. If we know that every 14 Gt of CO2 that we emit equals 1 ppm of increase in atmospheric CO2, and we know the temperature increase that we get from a change in atmospheric CO2, we can calculate the temperature increase we get directly from emissions. Unfortunately the relationship between atmospheric CO2 and temperature is logarithmic so you can't just say something like '100 Gt of emissions equals 1 degree Celsius', but it would allow me to convert that linked tool into one that's cumulative emissions -> temperature instead of atmospheric CO2 -> temperature. I'll think on this more and potentially make that tool.

The atmospheric CO2 levels are taken from Mauna Loa measurements.

The atmospheric CH4 levels are taken from a network of NOAA locations.

The annual CO2 emissions are taken from here.


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  2. I don't now how much you know, so I maybe repeating what you already know :)
    After some years, 20'ish to over 100 years, CH4 degrades into CO2 because of it's interaction with Hydroxyls. There are "technically" more hydroxyls in warmer temperatures.
    Trees and plants reached 'peak carbon' 10 years ago: Interview with the scientist here :
    (I listen to RadioEcoshock almost every week)
    I recently read in a paper that some tropical forests in the Amazon and in Bresil are emitting 450 millions tons of CO2/year. trees seem to be dying out.
    The other huge carbon sink, the oceans, seems to have slowed down it's CO2 intake, research should be available in a few years, it's just in discussions at the moment.
    Thank you for your blog