[silverquiet]

We can measure tiny increments of time to see really small effects on the Earth; it's a testament to how good a lot of our instruments are really.

What's scary to me is that the carbon content of the very air we breathe has increased by a third since the time when my mother was a child. That's hardly a small thing.

[apothegm]

Hm… humans (all mammals, really) react with great distress to high CO2 concentrations in the air. Now, the concentrations at which that reaction can be measured are MUCH higher than the current ones. But it does make me wonder whether we are reacting to them subconsciously anyway. That might help explain the increased incidence of anxiety and depression, among many other things.

[card_zero]

So from 0.03% to 0.04%, right.

[wongarsu]

More like from 0.02% to 0.04%. But at 0.1% people start complaining about drowsiness and at 0.2% you get worse concentration, loss of focus, increased heart rate, etc. Even if it didn't have such bad effects on the environment we live in we should stop pressing down the accelerator.

[card_zero]

Hmm, so like one seventh to one quarter of the way (depending which of us is counting) to feeling perceptibly close and stuffy. Useful context.

[silverquiet]

I once saw a photo of a pair of lumberjacks posing next to a giant redwood tree they had cut down with a long hand saw that they were able to push/pull together, and it struck me how amazing it was that with a tiny bit of metal and ingenuity, a pair of humans could take on a giant piece of nature (I suppose ironically made mostly of carbon) and topple it. It is really impressive what the right force applied to a system can do to destabilize it.

[card_zero]

Yes, and one part in ten thousand of the Earth's atmosphere is a very large volume (or mass). But you should be careful when you say things like "increased by a third" because it could confuse a stupid person, who then has to go and look it up.

[silverquiet]

Nothing about climate change is particularly "intuitive" - you can't see or smell carbon dioxide, and understanding of physics enough to model the greenhouse effect took humanity quite awhile to achieve (though obviously you can stand in an actual greenhouse to get some idea).

But the Earth is a rather large place and making significant changes (I suppose we can argue over what constitutes significant) to its very atmosphere is a profound thing. We are not the first to do so obviously; the first photosynthesizers left their waste oxygen behind which was rather bad news for a lot of the other life on Earth prior to them. I would have hoped that collectively humans might have more agency than bacteria, but when you look at a chart of carbon dioxide in the atmosphere, it is hard to make that argument.

[card_zero]

I did play with CO2 a lot when I was a kid, though. I used to buy the little canisters that serve some purpose or other for home brewing, and hammer nails through the ends so they went off like rockets and skittered all over the yard. There was a lot of visible gas, but maybe the expansion of the CO2 made it cold and so I was seeing condensing water? Also I played with the soda stream a lot, I think CO2 has a distinctive taste.

I enjoy referencing the oxygenation event extinction too. Goddam cyanobacteria, messing up the greenhouse for us archaea with their oxygen pollution.

[silverquiet]

Interesting point about CO2 - I'd assume your thought about condensation is correct, but it also occurs to me to wonder if it's a gas in those little canisters; a lot of the gas systems I've dealt with have a liquid phase somewhere in the loop.

And I didn't think that carbonated beverages had any difference in flavor, but a huge difference in texture/mouthfeel.

[Andrex]

That can't be a universal increase, can it?

I've been worried about smog, didn't think to track carbon penetration over the last few decades...

[silverquiet]

The world over; humanity has put more carbon into the air by weight than the total sum of all that we've built on the surface, and it's still accelerating. It's a rather awesome testament to humanity, but not exactly in the positive sense given that the externalities are beginning to bite.

[FredPret]

Check out the wonderful earth.nullschool.net.

Here's a link to global CO2 levels [0]. As I understand it, it's live data from satellites.

You can see it's lower (redder) where forests and plankton are growing, and higher (whiter) elsewhere. You'll also notice that it's pretty much the same everywhere - the range is only 400 - 450 ppm.

[0] https://earth.nullschool.net/#current/chem/surface/level/ove...