Hybrid Cars and Climate Change

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While high gas mileage often drives sales of hybrid cars, their comparatively low greenhouse gas (GHG) emissions also serve as a key selling point for consumers seeking ways to help with climate change.

The United States Environmental Protection Agency (EPA) notes that automobile choice accounts for a bit over fifty percent of greenhouse gas emissions for the average household.

Their review of some of the 2010 hybrid cars ranks them according to each car's carbon footprint.

The rankings are based on a formula that measures the fuel life cycle of the car with respect to carbon dioxide, nitrous oxide, and methane emissions. The results of the measurements fit along a scale with the a low score of 3.5 to a high score of 16.2.

The top five cars, all with a carbon footprint less than 5 are hybrids:

• Toyota Prius (4 cyl, 1.8 L, Automatic)- 3.7
• Honda Insight (4 cyl, 1.3 L, Auto(AV-S7))- 4.5
• Honda Insight (4 cyl, 1.3 L, Automatic (variable gear ratios)) - 4.5
• Ford Fusion Hybrid (FWD 4 cyl, 2.5 L, Automatic (variable gear ratios) - 4.7
• Mercury Milan Hybrid FWD 4 cyl, 2.5 L, Automatic (variable gear ratios) - 4.7

High gas mileage accounts for the greater part of the low carbon footprint scores for hybrids. The fact that hybrids move to electric power at idle, which produces zero emissions, also helps with their low carbon footprint scores.

On the other end of the scale, with a scale breaking 18.3 rating, the 12 cylinder Lamborghini Murcielago ranks as the automobile with the largest carbon footprint.

With a rating of 16.6, the 2009 Ferrari 612 Scaglietti lags only a little behind the Lamborghini.

Because the rankings rely heavily on fuel consumption, generally the non-hybrid subcompact and compact cars score the next lowest on the scale. Moving up to midsize and large cars often translates into decreased gas mileage and a higher carbon footprint score.

The popularity of Sports Utility Vehicles (SUVs) has led to the production of a few hybrid models. The Ford Escape Hybrid FWD, Mazda Tribute Hybrid 2WD and Mercury Mariner Hybrid FWD all come in at the top of the low carbon footprint scale with a 5.7 score.

© 2009. Patricia A. Michaels