There are some calculations that makes replacing a old gas or diesel powered car more environmentally friendly, as compered to buying a new electric car. I do wonder where the tipping point is though, and if there isn't an environmental argument to be made that not only should government bad the sale of new internal combustion engine cars, but they should also ban cars with an expected lifespan shorter than e.g. 15 - 20 years.
If externalities were correctly priced in to fuel, rare earths, rubber, road wear etc then it would be easy to see, the cheaper the better.
But they aren’t, not even close. Oil is massively subisidised by the military before the environmental costs. Brake particulates and tyres don’t cover the cost of microplastics and lung damage, heavy cars don’t pay anywhere near the damage they cause to the roads and bridges etc.
Due to this you can argue pretty much whatever you want by ignoring certain costs depending what you want to come out with.
My petrol car is 20 years old, it’s done 70,000 miles, it weighs about 1,000kg and burns through 300 litres of unleaded each year to do the 3,000 miles I do in it.
I suspect scrapping and replacing this with even a small electric car would not be globally environmentally worthwhile. There may be improvements to local air quality assuming regenerative breaking etc, that may be offset by increased tyre and road wear though, even ignoring the impact of the co2 to generate the 80kWh a year it would require.
20 year old cars tend to be heavy polluters because they don't meet the latest emissions standards. Here in California the state will buy old cars and scrap them to get dirty emitters out of service. Also, nearly every day electrical generation is over 50% using solar, wind or hydro so EVs are cleaner here than any ICE vehicle by far.
Well my 20 year old car meets the various clean air zone emission standards that newer cars fail to
However even if it didn’t, if I used it for 200 miles a year would it make sense to buy a new electric car?
It’s never clear cut, and it’s practically impossible to make the best decision in any given case. You can make a regulation which will on aggregate lead to less damage but there will always be exceptions, and on a case by case basis it’s extremely difficult to measure the damage a given scenario applies. How many “units of badness” does buying a new 2 ton electric car before you move it a single mile. Id wager it’s more than an existing petrol car burning 1 litre of unleaded petrol on existing tyres and brake discs.
The difficulty is measuring total impact of the choice. Sure buying a new petrol car and driving 20k miles a year for 6 years will be worse than buying a new electric car and driving 20k miles a year for 6 years. That’s not where the line is.
The calculation I've seen put it around 50k km, depends of how good the local grid is of course.
I'm pretty sure that holding onto my '98 Civic is more environmentally friendly than buying a new EV - especially since I only drive ~3000 miles/year (If I drove 10K+ miles/year then the calculation would likely skew towards an EV). The Civic still runs great and it's easy to repair when something does go wrong. And the mileage is quite good - ~30MPG combined (easily get 37MPG on the freeway).
That 1985 Toyota emits more GHG and NOx per mile than a new vehicle because it wasn't built to meet the latest US or Canadian emissions standards. Older vehicles emit more pollutants so in some US states the government will buy the car to have it scrapped, thus improving the overall fleet emissions statewide. In California there are owners who keep and maintain pre-1975 vehicles because they have little or no smog control systems, are easy to work on, and they are exempt from mandatory bi-annual smog testing.