Aug. 15, 2012 -- The 2012 Toyota Prius gets the best EPA-rated gas mileage -- 50 miles per gallon combined -- of any non-plug-in car sold in the United States.
With its top-of-the-list gas mileage, a Prius hybrid is clearly a step in the direction of driving green -- and all journeys begin with the first step. But by itself, owning a hybrid isn't enough.
Here are five reasons that just driving a Toyota Prius won't make a notable dent in the enormous task of saving the planet (however you may define that).
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A Hybrid Still Burns Gas
Unlike all-electric vehicles, the Toyota Prius Hybrid burns gasoline.
While their results vary in degree, two studies conclude that in many states, driving a mile in an all-electric car that was charged by a coal-powered electric grid produces less carbon dioxide than driving a mile in a gasoline-powered car that gets 25 miles to the gallon.
In states with the dirtiest grids -- like North Dakota and West Virginia, which use almost entirely coal -- the 50-mpg Prius rates slightly better for the environment. But as coal-powered plants are replaced with those powered by natural gas, solar and wind, the environmental advantage of a hybrid will go down.
Electric cars are mostly better now, and will get even cleaner over time -- unlike the Prius.
A Parked Car Uses Less Gas than a Mobile Hybrid
If you buy a 2011 Toyota Prius and drive it 100 miles a day for your commute to work, you would burn 500 gallons of gasoline a year. Whereas if you walked, bicycled, carpooled, or took mass transit to work, you wouldn't.
Unfortunately, 60 years' worth of U.S. zoning laws have trapped many of us into suburban sprawl that keeps commercial buildings -- be they stores or offices -- miles away from residences. That means a car becomes necessary even to get a gallon of milk. And outside a few major cities, mass transit is unappealing or nonexistent.
While most Americans say they would like to live much closer to their jobs, mixed-use neighborhoods that prioritize walking, biking and mass transit over single-occupant cars are often still viewed as something akin to socialism by local officials.
A Prius Hybrid Can't Keep Pace with Global Car Growth
We now have 1 billion vehicles on the planet, and by some estimates, we'll have 2 billion or more by 2050. In other words (well, just one word): China.
Today, only a tiny number of China's 1 billion-plus people have cars. That will change. Just to stay in the same place, the efficiency of every vehicle has to double. Owning a Prius won't have much of an impact on that fact.
Many scientists say that to stem the predicted effects of climate change, we must cut our carbon output up to 80 percent from today's levels. That will require far more radical changes than driving a hybrid vehicle.
Modern Life Generates CO2
One of our favorite book titles lately is "Time to Eat the Dog? The Real Guide to Sustainable Living", whose authors measured the environmental impact of modern lifestyles, such as owning a pet.
They conclude that adopting a dog or cat increases your family's carbon footprint because of the land needed to produce the food. For example, the land necessary to feed a medium-sized dog equals about 2 acres of land. That's twice as much land required to power a 4.6-liter gas-burning Toyota Land Cruiser. The "eco-footprint" of a cat is equal to that of a Volkswagen Golf.
We don't recommend cooking your cat, but if you're thinking about your pet having litters of adorable furry kittens or puppies -- think again.
More than that, cut out airplane flights. They comprise up to 80 percent of a frequent traveler's carbon footprint. The worst culprit? A dog that flies in a plane.
Family Planning Can Reduce CO2 Emissions
The widespread availabilityof family planning services and contraception could have a major impact on carbon emissions.
A London School of Economics report suggests for a cost of $6.70 per ton, family planning can eliminate atmospheric carbon -- a much cheaper investment than tweaking technology to improve a vehicle's efficiency, which can cost upwards of $31.70 a ton. Forgo the Prius and spend that money in a donation to Planned Parenthood. It might be more effective.
For more along these lines, see also our discussion of why gas-guzzlers will always be with us. We aren't saying you shouldn't by a Prius, but are saying that a Prius alone won't save the planet and you can do much more to reduce your carbon footprint.
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