[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.

[vel0city]

Carbonated beverages have carbonic acid in them (H2CO3). Even after all the bubbles are gone a carbonated drink will be more tart than a non-carbonated version of the same drink.

[card_zero]

So what exactly is visible in dry ice mist (see every 80s pop video)?

Edit: NM, Wikipedia says "condensing water vapor", indeed.

[silverquiet]

Yes, it's called dry ice because if you look at a phase diagram, a liquid can't exist at atmospheric pressure, so carbon dioxide ice transitions directly from solid to gas (called sublimating rather than evaporating/melting). One of those neat chemistry things.