California cars will be sold with yet another sticker on the shield: a mandatory label listing a car’s individual global warming score. The score will fall between 1 and 10, and will be calculated using figures that account for both fuel production and emissions from vehicle use.

The law officially goes into effect with the 2009 model year; cars don’t officially have to have the stickers until 2009 begins, but many cars are expected to have them sooner. Cars sold in California already have a similar sticker, scoring individual vehicles on their smog emissions.

In general, there are arguments against greening products through governmental policy. Consumers’ choices — such as refusing to buy gas-guzzling SUVs to save money — are what will really affect vehicle emissions. However, California’s approach looks likely to be more effective than the average environmental policy. Buyers can interpret a low global warming score as a mark of fuel efficiency. As a single digit number, it’s easier to base the decision to buy on that score, rather than trying to decide if a high MPG in the city or on the highway is more important.

California is the first state where this sort of sticker law will go into effect. New York has already passed a similar law, though, going into effect for the 2010 model year.

Photo — IwateBuddy