Might be a bit hard for you to buy depending on where you live but YABU energy drink is just straight up carbonated Polish apple juice with caffeine. I drank a few different flavours they have and they are nice.

When ice forms, it traps small airpockets in it, so we take samples of ice from the polar circles kilometres deep, date it, crush it to release the air pockets and measure the air contents. Then we can see how different the CO2 amounts were to now.

Source: there’s a fuck ton of different articles that talk about this, and this is the first one I found of Google, search yourself for more.