Ask Lemmy

Combustion produces byproducts, such as carbon monoxide, carbon dioxide, nitrogen oxides, and depending on the fuel or the quality of combustion, sulphur oxides and other fantastically poisonous substances that are building up in our limited breathing air and drinking water.

Engines that use this process are called internal combustion engines, they mix the fuel with air and ignite it, this creates heat and pressure, because the big molecules that make up the fuel are broken down into a massive quantity of smaller ones. That pressure then pushes on pistons which turn a crankshaft that can be connected to a transmission in a car, or a generator in a power plant, the hot exhaust gases that make up a lot of the pollution then get forced out of the engine into the air.

Unless you're asking why specifically those companies are the ones producing the emissions, in which case it's a matter of the amount of carbon fuel they use to mine/refine/move the materials and build/run the factories, and the transport they use to move their finished product and run all of the processes that lead up to the product being made. All of which drives emissions.

To draw on an example thats incredibly apt right now, considering Utah is now allowing a datacenter that will use 9 GW of power, more than every combined person and business in the state uses.

A data center is designed in CAD software - electrical energy from the grid is used in the computer

The data center is built - Heavy machinery prepares the ground and Concrete is poured - earthmovers use carbon fuel, the concrete manufacturer itself burns fuel to create the concrete, then ships it via trucks to the building site where it is poured, setting concrete also releases carbon dioxide.

The computer components are built - rare earth metals are dug from the ground and refined into chips that are shipped to factories where they are assembled onto circuitboards - the material and manufacture requirements of these components take a lot of fuel, and a lot of highly specialised equipment that is energy intensive

The computer components are shipped to the site - this also takes fuel.

This is all contributing to the emissions cost that the company has racked up, and the datacenter isn't even active yet.

ALSO, NONE of these examples take into account physical pollution, where crude oil or a carbon product (such as in Palestine... the American one; where a derailed train load of polyvinyl was set on fire and left to uncontrollably burn because it was cheaper than calling a chemical spill team) is either poured into the worlds water from crashed tankers or from drilling platforms (or from military actions where refineries are burned, and we get events like the mass swathe of marine life dieoff thanks to oil being spilled into the ocean)

Hopefully that answers your question, if not you'll have to ask a different way because I don't know what you mean when you say "why do they produce emissions?" (The answer is burning things makes emissions, and they're burning the lot.)