I added a "disclaimer" after the fact to mention that it's based on mileage way under what people actually drive and it doesn't take maintenance into consideration, with "real" mileage we're better off switching to an EV now because the switch makes you carbon negative after 5 years or so. The numbers used are appropriate in the sense that in both cases we don't count the CO2 coming from the production of the energy source used by either of them. If the vehicle life is the same, the 24 and 18 tons numbers (which seem to be under what would be expected based on the math I've done, that's a 10 years life expectancy for the gas car???) also show that the quicker we get rid of the gas cars, the quicker we reach a point where we're carbon negative compared to continuing to drive the gas cars until they're not drivable anymore.

If we go with a number much closer to the actual average (20k km/year) you can buy a new Corolla, replace it the next year with an EV, park the Corolla and never drive it again and the math goes like this:

5.6 (prod )+ 2.8 (scrap) + 3.2 (driving) + 8.8 (EV) = 20.4 tons

Years to reach 20.4 tons if we drive just the Corolla > 5.6 + (3.2 * X) >= 20.4? X = 5 years of ownership = 21.6 tons

After 4 years of owning the EV you're carbon negative in comparison.