Do catalytic converters on cars add to global warming?

Yes.

"Environmental impact

Catalytic converters have proven to be reliable devices and have been successful in reducing noxious tailpipe emissions. However, they may have some adverse environmental impacts in use:

The requirement for a rich burn engine to run at the stoichiometric point means it uses more fuel than a "lean burn" engine running at a mixture of 20:1 or less. This increases the amount of fossil fuel consumed and the carbon dioxide emissions of the vehicle. However, NOx control on lean burn engines is problematic at best, and many lean burn engine manufacturers are considering rich burn variations.[citation needed]

The manufacturing of catalytic converters requires palladium and/or platinum; a portion of the world supply of these precious metals is produced near the Russian city of Norilsk, with significant negative environmental effects."

A little. They place back-pressure on the combustion engine, which reduces efficiency, which means that you have to burn more fuel to get the same amount of power. I believe the efficiency hit is on the order of 2 to 5%...

NOx reductions don't have an impact on global temperature - they decrease ozone (which is a cooling effect), but it turns out that NOx reductions lead to increased methane concentrations (a warming effect). Reductions in VOCs (volatile organic carbon) might have a small cooling effect (they also reduce ozone) but probably smaller than the warming from the efficiency loss.

And the catalytic converter production process also takes some energy, and the device adds some weight to the car.

But the benefits of catalytic converters are more than large enough to outweigh these small penalties. There are better ways to reduce greenhouse gases. (also, don't remove your converter to try to improve gas mileage - your car has been tuned with back pressure in mind!)

Not significantly.

The CO and unburnt Hydrocarbons would probably mostly end up as CO2 eventually anyway and NOx also happen to be pretty strong greenhouse gases (along with causing smog). Besides, more than 99% of the fuel in any car that doesn't have something seriously wrong with it gets completely burnt so there isn't much going into the catalyst so even if the converter added to global warming the effect would be lost in the noise.

i do no longer understand fix estimating however the catalytic converter is under the automobile, so it is hit by making use of something run over, bumped against curbs and rocks, or (fantastically if youpersistent in snow because of salt) the pipes retaining it purely undemanding corroded away over the 18 or so years the automobile has been around. without it, you will on no account bypass an emissions attempt and threat besides the fact that your state has set as outcomes for noncompliance with the criteria. additionally, with exhaust exiting from under the automobile and not the rear, you additionally can threat carbon monoxide coming into the cabin.

No, because at best, it doesn't exist, and at worst, it's a natural process and not an Armageddon event.

No!