How much CO2 produced is actually used for something?

The vast majority of CO2 from burning fossil fuels goes straight into the air. But what percentage of produced CO2 is actually used for something? It is used in many different applications including paintball, fire suppression, dry ice, beverages, welding, and IIRC certain types of laser.

If you believe Wikipedia (there are references, but they’re behind paywalls), industrial CO[sub]2[/sub] is largely a by-product of hydrogen gas production. The reactants in this process are methane and water, and the net reaction would be

CH[sub]4[/sub] + 2 H[sub]2[/sub]O -> CO[sub]2[/sub] + 4 H[sub]2[/sub].

The main use of hydrogen is in industrial ammonia production, which is used in all sorts of other processes; so I would guess that this process would provide more than enough carbon dioxide to go around, and that companies wouldn’t bother with trying to extract the CO[sub]2[/sub] from the exhaust of a power plant solely to be able to resell it. The stuff that goes up the chimney of the power plant is probably a lot less pure than what suppliers can get from a more controlled industrial process.

Are you specifically only interested in human technological uses? Because plants use it in photosynthesis and the atmosphere uses it in the greenhouse effect to maintain the planet’s energy balance.

I was going to suggest CO[sub]2[/sub] as feedstock for industrial chemical synthesis, but I think MikeS beat me to that punch.

My company takes waste CO2 from large gas processing facilities, cools it down and puts it down oil wells to aid in fracking. We are investigated recollecting the gas as it comes back up the well, but currently it’s just vented back to the atmosphere.

I don’t know how much of all the CO2 produced is ‘used’ (pretty much all of it just ends up in the atmosphere anyway), but I would guess it’s well south of 1%.

IIRC, that big gasification plant in ND has a pipeline selling CO2 to oil producers in Canada. I also recall a CO2 shortage in TX a few years back.

But I can’t help the OP much with numbers.

There are polycarbonates that use CO2 as a monomer, but I don’t know if any are commercial.

Um, plant photosynthesis?

Aside: My mom was once involved with a passive-solar greenhouse project, sponsored in part by a local microbrewery (they wanted year-round fresh herbs and salad greens, for their in-house restaurant). It turned out that the limiting factor on plant growth in the greenhouse was the CO2 inside, since it was so well-sealed to prevent heat loss. She lamented that the greenhouse was a mile away from the brewery, instead of on-site, because the brewery produced huge amounts of CO2 that they would have loved to put to good use.