Not possible to do myself, and it's not feasible to pay someone to do it. I don't have the tools, the electronics, nor the replacement parts (not to mention knowledge or time) to keep a modern car going for the remaining 30-50 years of my lifetime. Attempting to fix it at the point where everything is falling apart becomes impractical (as I keep trying to tell my dad when he's spending even more money to make a '79 truck run).
Not to mention that getting those parts custom made or shipped to you from across the country incurs its own environmental penalty.
> Eat less meat.
I've found that, to keep a balanced diet without meat, it's quite a bit more expensive, and exceptionally more time consuming. Then there's the health issues (like those outlined in the scar study featured on HN a week or so ago).
I absolutely could compromise my health and lifespan for the sake of the world, but I'm not going to.
> Consuming less, buying less.
There's a lower limit to how much less you can do and still remain as a healthy, productive adult, but I agree that it's a good thing to do for many reasons; it's something I try and do.
Even if I took every step outlined, it would have, effectively, no impact on the environment.