Why do we need to be subtle in dealing with gas guzzlers?

While walking through London I was hit once again by the obscene numbers of gas guzzling cars. There were lots of 4x4s of course, but big saloons, lots of sports cars, and plenty of big expensive motors.

Now so far the government approach to discouraging gas guzzlers has been at best a tweak. I say forget this and go in hard! My plan would therefore be to announce that in 3 years' time Road Tax on cars under 1000cc would be nil, on cars 1000 to 1500 it would be the same as now, on 1500 to 2000 it would be three times the current rate, and on cars over 2000 it would be ten times the current rate. At the same time I would remove all duty on biofuels. Equally I would make all cars over 2000cc pay £25 for congestion charge.

This isn't subtle. It doesn't address every nuance of the issues. So what - our aim is to reduce carbon emissions, pollution, and road congestion. So what that many old cars are much bigger polluters than new cars (the dust to dust carbon footprint is still probably lower than buying a new car). I say that this would be crude but effective. It is not so hard that people will simply revolt. Its tough love and I think the planet needs that right now.