we might have to start i dunno tyring off lights, things on standby etc etc which might have to make up the shortfall else where...
We can do that
and work on decreasing CO2 emissions from cars - the two are not mutually exclusive.
@Bob: The difference between home heating and gas-guzzling cars is that heating your home is not a choice, while choosing to buy a car that's known for being a heavily polluting vehicle is.
You can help by using
less heating at home, not leaving heaters on, making sure you're well-insulated, and so on, but, for most people, there isn't a lower-emissions form of home heating they can choose. If you're in a flat, or if you rent, there isn't even much you can do about insulation. So we can reduce our home energy impact, but not by all that much, and we certainly can't give it up altogether.
With cars you do have the choice; most people have a choice of getting a car or usng public transport, but even those who do
have to have a car have a choice over which car they get. If you go for a car which will cause more damage, then you have no-one to blame but yourself when you're charged more for using it.
BTW: the bulk of the car is important when it comes to collisions, especially collisions with pedestrians - it's just so much harder to see kids crossing the road when you're high up in the air. The weight of the car also affects wear and tear on the road. So, while they don't affect congestion per se, they do have negative effects. Of course, cars that are zero-emissions tend be lighter in order to use less energy, which usually means they're smaller in dimensions too.