Driving Up Emissions Transportation and Greenhouse Gases

When Henry Ford innovated the mass production line, he made ownership of the Model T a possibility for average wage earners. The Model T led to faster and bigger cars. And the car transformed the culture of North America. Urban landscapes shifted from focusing on impressive architecture, street cars, and pedestrian access to giving planning preference to cars. Pedestrians and cyclists weren't as important as parking lots and highways. Drive-throughs replaced the corner soda shop. Los Angeles, arguably the apex for car culture, even pioneered drive-through funeral parlors. North America's love affair with the car changed everything — including the atmosphere. Increasingly, the car is also becoming a "necessity" for large numbers of people in the developing world.

About 14 percent of all greenhouse gas emissions come from moving people and goods, according to the World Resources Institute. In Canada and the U.S., the proportion is higher — closer to one third of emissions come from transportation. Almost all our transportation — about 95 percent, says the Intergovernmental Panel on Climate Change (IPCC) — runs on oil-based fuels such as diesel and gas, which explains why transportation accounts for such a large portion of overall emissions. Cars and diesel trucks are the top two offenders, but ships, airplanes, trains, and buses play a part, too. Figure 6-1 shows the breakdown of how each mode of transportation contributes to greenhouse gas emissions. (Refer to Chapter 5 for more information about the problems related to shipping goods.)


A car engine runs on a simple combustion system. Each time you press on the accelerator, gas flows into the engine cylinder, where the spark plug ignites it. The piston goes down, and the crank shaft goes around and turns the wheels. That mini-explosion also creates exhaust fumes that get pushed out of the tailpipe. Those fumes include a healthy dose (figuratively speaking) of greenhouse gases, including carbon dioxide, nitrogen oxides, and hydrocarbons. The exhaust also contains carcinogens (such as benzene), volatile organic compounds (solvents that immediately evaporate into the air), carbon monoxide, and other nasties.

Whether you need to run errands or drive the kids to soccer practice, cars, minivans, and SUVs are useful and often perceived as necessary. Most households in industrialized countries own at least one car because most cities and housing developments are built around road infrastructure — making it difficult to survive without one. The majority of people in the developing world still don't have access to a personal vehicle — but that's quickly changing.

China is soaring ahead in private car ownership, which jumped by 33.5 percent from 2005 to 2006, bringing the total to 11.49 million cars, according to the National Bureau of Statistics of China. Nevertheless, with one billion people, China's car population is far smaller than that of the United States.

Transportation Greenhouse Gas Emissions by Source

Figure 6-1:

Passenger cars lead the way in terms of greenhouse gas emissions.

Figure 6-1:

Passenger cars lead the way in terms of greenhouse gas emissions.


Planes burn fuel similar to kerosene, which gives off more emissions than the gasoline in your family car. The IPCC estimates that commercial airline emissions account for 2 percent of worldwide CO2 emissions — not too bad, except that it's expected to rise to 10 to 17 percent of total greenhouse gas emissions by 2050 at the rate humanity is globe-trotting. People made about 4 billion individual plane trips in 2007, for business or pleasure, and civilization is due to hit 5 billion trips a year in 2010 if it doesn't change its ways.

With countries rapidly developing around the world, international arrivals increased from 800 million to 900 million in just two years, according to the United Nations World Tourism Organization. The people of China are just beginning to tour their own country. They'll begin to travel and work abroad in great numbers soon. Experts predict that China will have 100 million outbound tourists annually by the year 2020, up from 12 million in 2001 and 20 million in 2003. This 100 million would be fourth in the world, behind only the United States, Japan, and Germany.

Flights are becoming cheaper (some European airlines are even offering $1 flights, for which the customer pays only the tax), and when they become cheaper, more of us are able to fly. Today, young adults commonly have flown internationally by the time they're 25. Zoe flew often before she realized the impact of her actions — amounting to a total of over 23 metric tons of greenhouse gases by the time she was 20. Good thing she carbon offsets (taxes herself by putting money into a project that will reduce emissions somewhere else) and now takes the train whenever she can. (Check out Chapter 17 for more about green travel options.)

Not only does flying emit a lot of greenhouse gases, it emits them in the atmosphere in a more damaging way. The warming impact of the exhaust from air travel is far worse than the same volume of greenhouse gases emitted on the ground.

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