Too much CO2? There are several ways to deal with it, many of THOSE solutions create a secondary problem such as heat. Here are a few ways to deal with CO2 in order of feasibility.
Dig a gigantic basement, and keep building it down. The CO2 is heavy and will sink into it. But you need to build passageways wider than one square so the gasses can circulate because materials won't share a hex so one square wide would be very difficult for gas to exchange through, the co2 would take a LONG time to settle down. A shaft two squares wide is good, three squares is usually sufficient.
Oxyferns are excellent but slow, but hard to come by. I always choose them from the lottery, but you'll never have enough.
Terraria deletes CO2, but uses lots of water. By the time I can build a farm, usually a better solution comes along.
Slicksters eat LARGE quantities of CO2 which is great, while producing oil and meat but requiring heat. This is more of a late game solution because you need to find them, and also manage the heat associated with their living conditions.
A CO2 scrubbers deletes CO2 and generates heat. You'd have to deal with the heat.
Bottle it. (You can do this by filling a tank then deleting the tank)
Dump it to space.

Generally, you want to buy time by getting the co2 out of the breathing area without actually doing anything with it, and then actually deal with it later when you have the tech to do so.

Just like in real-life, everything you do in this game makes heat. Even cooling an area locally, creates heat, just like running a refrigerator or an air-conditioner - you are cooling locally but actually increasing the amount of heat (loose energy) in the universe and in your room. In other words, leaving the refrigerator door open actually heats your house.

For our purposes "heat" is a "low-useable" form of energy and typically undesirable. Unless exposed to space, heat builds up in your asteroid and must be dealt with one way or another. (Space does not accept heat well because it is mostly vaccum. But some heat is conducted to space, and also some heat is convected to space in the form of radiation).

The beginning of the universe was the most useable form of energy, and it's all been downhill from there. Globally, everything in the universe takes more-useable energy and transforms it into "less useable" forms of energy. What is the meaning of life? Life exists because life is good at converting highly-useable energy into less-useable energy. Life is a mechanism to speed entropy. This will continue until all energy is equally distributed throughout the universe and everything in the universe is dead.

We can't do anything about that for the moment, so for now, we want to get the heat out of the dupes garden area. Dupes tolerate medium heat, so don't worry about the dupes themselves, but dupes need food. Thistles only tolerate low heat. As long as you are farming thistles, you need to be able to cool the area where they are growing. You need to "get rid of heat".

Early game, a great way to move heat around is to mix the heat with the frozen biomes.
Wherever you need to remove heat from, build temperature-conductive liquid piping there.
Then build insulated pipes toward the cold biome. Then build temperature-conductive pipes in the cold biome. This setup heats the fluid in the pipe, runs it to the cold biome, where the cold pipes suck the heat out. PH2O (pee-water) is great for this because it has a high heat-capacity. Later you can research better materials.
Unlike real life, you only need to start the liquid flowing once, and it will continue forever because there is no friction in this game.
Be careful because if you leave this fluid running, and the hot area cools down or you turn off whatever is generating heat, eventually the liquid will freeze in the pipes in the cold zone. You will need switches and bypasses and tanks to be able to stop the water from going to the cold zone when the liquid is too cold upon return, and risks freezing. This gets tedious to manage by hand and you'll make mistakes, so better to automate using thermometers to control the switches. (For example, when the liquid returning to the cold biome is below 10C, divert it into a tank instead of going through the cold zone again, which then returns the cool water to the warm zone until it does get warm enough to be run through the cold zone.)

The cold biomes will last a lot longer if you do not dig the ice. It is twice as effective to allow the ice to thaw away, then rebuild pipe in the newly cleared zone, and repeat when needed. You can dump a LOT of heat into a cold biome.
This is because digging a material erases half the mass, which means you lose half the cooling ability. Better to melt the cold material instead of digging into it.

If you are using a shutoff valve and the wrong stuff is going through you probably have a pipe connection a difficult to see incorrect pipe connection (usually connected behind the shutoff-valve). Delete all the pipe and lay it again and it will work.

If any machine doesn't work, you probably have one speck of the wrong fluid blocking the machine. Delete the pipes and relay with the known to be correct fluid and it will work.

Unlike reality, in this game, two types of materials cannot occupy the same square. It's for simplicityies sake and it's not how things work in the real world - but get used to it. If this game DID model the real world then you would need all the processing power in the universe to properly model the world. This game is designed to work on single crappy computers. So materials don't mix. Get used to it. It's still roughly correct. It's a game.

The most valuable resource in this game is the dupes time. You want to automate as much as possible. The goal of the game, as indicated in the first dialogue box, is to dig to the surface and "escape" (more will be revealed when you get to the surface).

Liquid and gas Bridges. I thought these were simply overpasses aka "bridge" since that is what they named, but they are also something else, and more, very confusing I know. They also control direction, and they also control priority. "Bridges" are the only way to accomplish many pathing choices.

1) if a bridge joins another line, the joining bridge will ONLY flow when there is "room" (aka the "main" line takes precedence). You can use this to sort materials, or to use one source first and the backup only if necessary, but only when you understand how priority works, it's not obvious.

2) Bridges control direction. Green goes to white, if you place a white between two greens flow will stop because they are both trying to get to it.
If a lane won't flow, place a bridge to guarantee direction, and delete the pipe)underneath the bridge. If you think a line should flow and it's not, it's 100% because there are two greens "fighting" for a white, so place a bridge to guarantee direction.

3) A bridge leaving a pipeline says "all flows through this FIRST until it is full, THEN flow past it." A bridge has higher priority than the mainline.

All these rules apply whether you want them to or not (for example if you want a simple bridge to only skip over something, too bad, all of these rules are going to ALSO apply, and could affect the way things work downstream. My advice is to understand how non-intuitively bridges work, or you'll get frustrated.

4) oh yeah, and bridges can also be used as bridges.

Green can flow past green if there is a white down the line. White can flow past white down a path unopposed by green (or orange). But a white with a green on each side can cause confusion because they both want to reach it. Better to join the two greens before meeting the white. Or drop the white part of a bridge between the two greens. It doesn't exactly work like real life.

When you deconstruct a bridge it doesn't drop any liquid so it's good to have some now and then for when you want to change the piping (which you will want to). All these rules apply to liquid gas and solid-conveyor.

Power doesn't behave the way I guessed it would. It's not like extension cords, it's more like one big circuit and the same current is running through the entire circuit.
Each appliance attached gets the full amount on the line - you cannot run a line to an appliance that only supplies as much as needed. Instead they all sip off the same line so you have to be careful to not put more devices than the line can handle, or to not supply more power to the circuit than the wire can handle. You can do things such as running only certain machines at certain times, turning off machines or subcircuits, using automation to open and close circuits. You can't afford to build the big wires all over the place, also they take a lot of space. So you need to get creative with the small wires. At least until later. You can also build some subcircuits of short lengths of thick wire for large machinery. But it has to be separate or has to have transformers that don't allow it to overload the small-wire circuit.

Basic line is good for 1k, if you draw more than that, you short the line. A transformer can be used to only allow 1k to that circuit, to prevent shorts. (You can have more than 1k worth of machinery as long as they aren't all on at the same time). It's not a normal transformer, it's more like a limiter, all it does is limit the amount of wattage through.

Power does NOT trickle back from the supply side of the transformer to the generating/storage side. It allows 200j per 1/5 of a second, which is the time of a "tick" or moment of the game.

Do not create a loop because then the battery can feed the transformer which feeds the battery recursively, overloading.

In the early game, use the pedowheels for a while to generate power. Then you can add a coal burner, but it's going to generate CO2 and heat so avoid using it as much as possible. Until you can deal with the CO2 and the heat. Coal should be a backup power, only.
Natural gas is better but creates pH20, which can be a good thing when you are able to filter it into O2.,
Solar is great but limited. You want to use automation to help store solar to batteries that gets used during the night then kicks on coal when solar runs out.

Petroleum makes a LOT of power and a LOT of CO2 and a LOT of heat.

Ideally you can make a room under a steam turbine and in that room is a volcano AND foundry and other heat producing machines such that all the heat generated is converted to energy, instead of having to treat it as a "problem". Of course building such a room is a big deal and requires medium-high technology level materials.