The verdict appears to be that the answer to this question is a bit more complicated then a blanket "Its better to buy a new car for the environment" but its highly dependent on gas milage and time of ownership, as well as new gas car vs new hybrid car vs new electric car. He does take into account carbon needed to build the cars too. It seems that in most cases a new EV will be better for the environment then your 10 year old honda in roughly 4 years. Skip to 6 minutes in the video for when he starts showing compiled data of when its better to buy a new car vs keep old.
https://www.youtube.com/watch?v=L2IKCdnzl5k
The verdict appears to be that the answer to this question is a bit more complicated then a blanket "Its better to buy a new car for the environment" but its highly dependent on gas milage and time of ownership, as well as new gas car vs new hybrid car vs new electric car. He does take into account carbon needed to build the cars too. It seems that in most cases a new EV will be better for the environment then your 10 year old honda in roughly 4 years. Skip to 6 minutes in the video for when he starts showing compiled data of when its better to buy a new car vs keep old.