Light duty vehicles make up about a bit over half of the transportation sector's 28% contribution to global greenhouse gas emissions.

https://www.epa.gov/greenvehicles/fast-facts-transportation-...

So if every personal vehicle on the planet was an EV charged by a renewable energy source, we would cut GHGs by ~17%

That's US where everyone drives everywhere. Now we do the same for Europe or China and the effect on the whole world ends up much less.

It will make a noticeable difference but “big” is a ultimately a value judgement. Cars are small potatoes compared to industrial polluters. Huge companies that are actually meaningfully responsible for waste have been trying to put the blame on individuals for decades. Like in a tiny sense they have a point because they’re delivering products and services to individuals but they’re also pushing all the externalities of their waste onto individuals who have very little power to make systematic change while making sure that we can’t act collectively through government.

Non-energy example: trash. Jesus lord I am swimming in trash. Not because I consume in excess but because the everyday things I need come with stupid amounts of packaging that I can’t give back to them and isn’t recyclable or reusable.

Absolutely. In the large scale of things optimizing already efficient fossil fuel machines does not bring much savings compared to optimizing heating and cooling and buildings that are using that.

Not to mention the enormous amounts of energy used in manufacturing/heavy industry. China's Top 5 emitting industries have nothing to do with transportation of individuals or farming for food, unlike some parts of the world.

There is more to the switch from ICE to electric than pure CO2 output, air quality in population centers is a big part of it too. Particulates from vehicles are a health epidemic, and whilst not all of it comes from the tailpipe it's certainly a not insignificant amount.

I don't disagree that heavy industry is going to be the more important problem to solve, but unfortunately I have few levers at my disposal to influence that. It's going to take treaties, taxes, regulation and sanctions to figure that mess out. Because I have zero faith in that actually occurring, I think the real solution is going to be in remediation technologies. Consumerism isn't going away, especially with fresh faces entering the developed world, eager to take up any slack the west gives.