California to Rate Cars on Global Warming in the New Year

Car buyers in California could be getting a different kind of sticker shock in the new year. Starting Jan. 1, every 2009 model year and newer car sold in California will be required to carry a label that ranks, in addition to the existing requisite smog ratings, the vehicle’s global warming impact.

California’s Air Resources Board said the new label will have two scores on a scale of 1-10 — one for smog and the other for global warming — with the average new car scoring five on both. The higher the score, the more environmentally friendly the car.

1The Global Warming Score is based on the vehicle’s greenhouse gas emissions, with 1 being 520 CO2-equivalent grams per mile and up, and 10 being less than 200. The board said the scores are adjusted to reflect the contribution of emissions from the production and distribution of the fuel used.

The Smog Score, which started showing up on new cars sold in California with the 1998 models, ranks each vehicle’s pollutant levels of non-methane organic gases and nitrogen oxides relative to other vehicles within that model year.

Even if you’re not in California, you can take advantage of the new scoring system by surfing over to, which offers up information from the Air Resources Board on the cleanest and most efficient cars available. You can’t search by Global Warming Score yet, but a number of small, low-speed electric vehicles come out on top of the Smog Score rankings, with highway-speed cars led by Tesla’s electric Roadster and the Toyota (s tm) Prius hybrid.

The new Global Warming Score was put into effect as the result of Assembly Bill 1229 that was signed into law in 2005.