Air Travel Reaches New Heights

In 2005, the number of passengers traveling on scheduled airlines in a single year passed 2 billion for the first time, according to provisional estimates from the International Civil Aviation Organization (ICAO).1 (See Figure 1.) And travelers flew an unprecedented distance— more than 3.7 trillion passenger-kilometers.2 (See Figure 2.) This is equivalent to 4.8 million people flying to the moon and back in one year.

ICAO numbers are an underestimate of total plane travel, as they do not include military aviation or the private and business jet industry that is so popular with politicians, business people, and celebrities.3 Some 4,000 new private and business planes were built in 2006, at a record cost of $18.8 billion, up 21 percent from 2005.4 (See Figure 3.) Private planes emit up to four tons of carbon dioxide per hour and carry few people, so the pollution-per-passenger ratio is much greater than on commercial flights.5

Due to war, terrorism, disease outbreaks, and rising fuel costs, the global airline industry has not turned a profit since 2000, though the International Air Transport Association expects an industry-wide profit of $2.5 billion in 2007, a profit margin of 0.5 percent.6 All regions except Africa are expected to be profitable.7

As the number of passengers flying each year grows, so does aviation-related pollution. One airplane crossing the Atlantic can use 60,000 liters of fuel—about as much as a driver uses in 50 years.8 The Intergovernmental Panel on Climate Change reports that in 1992, the last year with data available, air transport contributed 2 percent of global carbon dioxide emissions but nearly all of the nitrogen oxide emissions found 8–15 kilometers above Earth.9 Because the emissions from planes occur so high in the atmosphere, they contribute to global warming at two to four times the rate of emissions closer to Earth, such as those from cars.10

Currently, emissions produced on international flights are not explicitly regulated by the Kyoto Protocol, though those produced during domestic flights are included in country-specific targets.11 The ICAO expects to issue guidelines for emissions trading related to international aviation in September 2007.12

Within the European Union (EU), by 2011 airlines will be accountable for emissions from all domestic air travel and flights between member countries under the EU Emissions Trading Scheme (ETS).13 And in 2012, all flights arriving at or departing from an EU airport will be subject to ETS, with caps set at the average level of emissions between 2004 and 2006.14

One way to reduce the emissions caused by flying is to improve international air traffic management. Cutting flight times and making routes more efficient would avoid an estimated 73 million tons of carbon emissions each year.15 Virgin Air is experimenting with electric tractors that tow planes from gates to the runway, saving up to 2,500 liters of fuel per flight.16

Aircraft design matters immensely: new airplanes are 70 percent more fuel-efficient than those designed 40 years ago and 20 percent more efficient than those built just 10 years ago.17 High fuel prices provide a continued incentive to design more-efficient planes. Future planes may have longer, lighter wings with engines mounted at the tips, which would reduce drag and cut plane weight.18

Noise and material waste are also significant environmental concerns. The Natural Resources Defense Council reports that the U.S. airline industry throws away enough aluminum cans each year to build 58 Boeing 747 airplanes.19 Paper is the largest category of waste generated by the industry.20

Some airports are taking their environmental records seriously. Japan’s Centrair Airport, opened in 2005, was built on an artificial island to minimize noise and air pollution over nearby communities.21 The island was carefully shaped to preserve existing ocean currents, and a hydrogen fuel cell bus ferries passengers between terminals.22 In 2006 Boston’s Logan Airport Terminal A became the first U.S. airport to receive the Green Building Council’s Leadership in Energy and Environmental Design certi- fication for, among other features, its natural lighting, energy-saving roof design, and use of paints and sealants with low volatile organic compounds.23