Cars are as American as apple pie but our affection for the automobile has staggering environmental implications. The United States leads the global auto market, followed by China, after bumping Japan out of the number two ranking in 2006. The average US household has two mid-sized vehicles, which each emit upwards of 10,000 pounds of carbon dioxide every year. Every gallon of gasoline burned releases 20 pounds of CO2 making the transportation sector responsible for about a quarter of overall US carbon dioxide emissions. And because no combustion is perfectly clean, cars are also a primary source of local air pollution.
In July 2007, foreign automakers outsold the domestic “Big Three”—General Motors, Ford, and Chrysler—for the first time in history. An overall decline in sales, blamed on rising fuel prices and other economic concerns, also affected foreign automakers despite representing a majority of the market. For example, sales of most of Japanese automaker Toyota’s models were down with the exception of the Prius, a hybrid car.
This is perhaps a harbinger of things to come as the movement towards green, fuel-efficient vehicles gains momentum. If the fuel efficiency of all US passenger cars improved by 5 mpg, over 13 billion gallons of gas would be saved annually—equivalent to the CO2 emissions of over 11 million homes in a year.
But high emissions aren't the only environmental problem shadowing the auto industry. The resources and energy required to make new vehicles is also fairly monumental. The manufacturing of a vehicle accounts for 10 percent of its total energy impact (via fuel use), while the release of toxic substances occurs heavily during its production stages and not during its usage.
And although the environmental impact of automobiles is largely associated with usage, production also plays a role beginning with the mining of iron ore that is transformed into the steel that accounts for a majority of a vehicles total mass. Petroleum-derived, difficult-to-recycle plastic is also associated with energy use, air pollution, and the release of toxic substances in auto production.
Additionally, the painting and coating that takes place during the assembly stage of a car contributes to 90 percent of air pollution (40 million pounds) and the 46 percent of hazardous wastes (24 million pounds) at auto assembly plants. Other substances that are used in car production but aren’t found in the final product include toxic solvents like toluene and methyl ethyl ketone alongside phosphates and sulfides. It's estimated that approximately 30,000 pounds of waste materials are generated by producing a single car.
While the best car is no car at all, sometimes it’s impossible to do without. In addition to habits like slowing down, maintaining your car, and carpooling when possible, consumers have opportunity to choose vehicles that emit less greenhouse gases and receive agreeable fuel economy.
Hybrid-electric cars—named for their combination of conventional gasoline power and assistance from an electric motor—have been on sale in the US since the launch of the Honda Insight in the 2000 model year; they use advanced technology to provide higher fuel economy and lower emissions than are possible with conventional engines. New, clean diesels—known for their combination of efficiency and responsive performance—are making a comeback after disappearing from the domestic market in the early 1980s.
Alternative fuel vehicles (AFVs) have the ability to run on biofuels and other non-petroleum substances such as biodiesel and ethanol with little or no engine modification, depending on the "blend" of biofuel used. Biodiesel-compatible cars (essentially any vehicle with an unmodified diesel engine) can be powered with a blend (or non-blend) of fuel made from vegetable oils (in the US, usually soybean oil) and petroleum-based diesel. B20—a blend of 20 percent biodiesel and 80 percent petrodiesel—is increasingly available to consumers.
Automobiles with the ability to run on ethanol blends such as E85 (85 percent ethanol and 15 percent gasoline), are considered to be flex-fuel. Ethanol like, biodiesel, comes from a natural, renewable resource (in this case, corn), decreasing dependence on foreign fossil fuels and generating domestic agricultural activity. Other less common or in-development alternative fuels include electricity, hydrogen, and propane.
While the economic and environmental strengths of biofuels—E85 and B20, for instance—as renewable byproducts of domestic agriculture are touted by many, critics see the shift away from fossil fuels as a risky one. Growing enough crops—soybeans for example—could lead to deforestation to meet increasing demand. Additionally, given biofuel's origin in crop-based agriculture, the issue of pesticide use and genetic modification have been brought to light.
In fact, substituting 5 percent of the domestic petrodiesel supply with biodiesel would result in 60 percent of the soybean supply being exclusively allotted to biodiesel production, restricting its role as a source of food and fiber. This point is made explicit in a March, 2007 article published in The Guardian. Writer George Monbiot argues that the demand for crops as a fuel source will consequentially raise the price of crops as a food source, leading to widespread food shortages and starvation.
Monbiot also asserts that the harvesting of palm oil in Indonesia for the European biodiesel market is responsible for rampant destruction of rainforests and the near extinction of the orangutan, adding that the burning of native forests to make way for palm oil releases ten times the amount of carbon dioxide as petroleum does into the atmosphere. He suggests discontinuing biodiesel and other biofuel production until more effective, large-scale production methods become available.
Following the oil crisis of 1973, Congress in 1975 enacted a regulation called Corporate Average Fuel Economy (CAFE) to improve the fuel efficiency of personal vehicles sold in the US. CAFE has garnered criticism from all sides: environmentalists argue that the standard isn't high enough, free-market advocates claim it limits choice and potentially decreases safety by encouraging the use of lighter vehicles. Still others feel it unfavorably benefits foreign automakers, who tend to produce smaller, more fuel-efficient cars.
Automakers in particular have criticized CAFE. Bob Lutz, Vice Chairman of Product Development at General Motors, declared that forcing automakers to sell smaller cars to improve fuel economy is like “fighting the nation’s obesity problem by forcing clothing manufacturers to sell garments in only small sizes.” The Alliance of Automobile Manufacturers—an industry group that represents all major automakers but Honda–lobbies to reform or scrap CAFE.
Whether CAFE has improved fuel economy is a topic of considerable debate. Since 1980, average fuel economy has remained relatively flat. At the same time, however, automobiles have become safer, quieter, larger, heavier, and considerably more powerful. Recently, California and other states have sued the Environmental Protection Agency to regulate CO2 emissions from automobiles beginning in 2009—a de facto regulation of fuel economy.
Tax breaks and subsidies
Numerous incentives are extended to buyers of green vehicles, particularly hybrids. For specific hybrid incentives—federal, state, or private—see Hybrid Center’s Consumer Center. In addition to federal tax credits and monetary incentives offered by individual states, hybrids are eligible for perks and privileges that include usage of high occupancy vehicle lanes (HOV or carpool lanes) regardless of the number of passengers, free and/or reduced-rate parking, and discounts within the hotel and insurance sectors. Additionally, Google and Timberland are among companies that reward employees for purchasing hybrid vehicles with handsome incentives.
Preferential treatment of hybrid owners has not escaped censure however, specifically in the case of HOV lane privileges. Critics feel that solo-motorist hybrids will contribute to congestion and emit more pollutants than non-hybrids traveling with multiple passengers.
Although drivers who fuel their cars with biodiesel, ethanol, or other alternative fuels may not receive the same widespread perks and privileges bestowed upon hybrid car owners, there are federal and state incentives and laws aiming to reward both consumers and producers of alternative fuels. See the Alternative Fuels Data Center for more specific information.
Related health issues
Aside from the global warming gas carbon dioxide, three major pollutants emitted by automobiles—hydrocarbons, carbon monoxide, and nitrogen oxide—also pose dire risks to human health. Specifically, when hydrocarbons and nitrogen oxide mix in sunlight and high temperatures, ground-level ozone is created. This leads to coughing, wheezing and eye irritation, and can result in chronic lung problems. Carbon monoxide decreases levels of oxygen in the bloodstream and affects mental and visual functions.
Automobile emissions in the United States have been regulated since the 1966 model year, following research that linked car exhaust with smog in Los Angeles. At the time, cars emitted nearly 13 grams per mile of hydrocarbons (HC), 3.6 grams per mile of nitrogen oxides (NOx), and 87 grams per mile of carbon monoxide (CO). Today’s standards are 0.25 gram per mile of HC, 0.4 gram per mile of NOx, and 3.4 grams per mile of CO.
- automotive fuel economy: Fuel economy in cars is important because carbon dioxide emissions are directly related to the amount of fuel burned. MPG, or "miles per gallon," is the way most Americans measure fuel economy. (Europe, for example, uses l/100km or liters of fuel per 100km traveled.) To measure your fuel economy, fill your tank and reset the odometer. At your next fill-up, divide the miles traveled by the amount of fuel needed to refill the tank.
- genetically modified organism: A GMO is created by merging the genetic make-up of two organisms, resulting in a desired byproduct that could otherwise not be found in nature. Engineering GMOs is a common practice in conventional farming, and studies have shown that GMOs pose significant environmental risks such as killing off living, natural organisms and becoming immune to pesticides.
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