Flying the dirty skies: environmental fallout from the low-budget travel craze.

It has never been easier to fly. Internet-based services and third-party affiliates like Travelocity.com and Cheap Tickets.com now offer plane tickets at all-time lows, conveniently purchased with a simple click of the mouse. It is possible to find flights online between European cities for less than the equivalent of $20, and web based carriers in the U.S. offer tickets from coast to coast starting at $99 and between regional cities for as little as $39.

While these flares may seem like a dream come true for low-budget travelers, the resulting surge in air traffic carries with it major environmental costs. Even with the more fuel-efficient technology that has evolved over the last 30 years, air travel remains a significant contributor to climate change. Currently, 600 million tons of carbon dioxide (CO2) are pumped into the atmosphere each year from commercial jets alone, while the number of planes in the air climbs steadily higher.

Commercial passenger airlines, especially low cost and Internet sales-based carriers, are experiencing growth internationally. In the United States, airline flight sales dropped 30 percent directly following September 11, but have since made a comeback and are now experiencing slow but steady growth.

Today, the U.S. has been able to maintain its place as the leading nation in air travel, and North America accounts for 40 percent of worldwide air traffic. Low-cost airlines such as Jet Blue Airways have led this domestic growth, topping the Bureau of Transportation charts for domestic profit gains. While most discount airlines have more fuel-efficient fleets than older carriers, their significant contribution to sky traffic is unprecedented. Elisa Lynch, global warming campaign director for Blue water Network, points out that "this issue also has to do with making sure that we're not traveling more than we need to. We have to look at the lifestyle we're choosing and its effect on the climate." Low-priced airline tickets make it easy to justify a mobile lifestyle.

In Europe, Internet ticket sales' have led to an explosion of short-distance flights and an increased demand for air travel, which in turn has spurred new airport development projects. The Sustainable Development Commission, which advises the British government on the environmental effects of development, criticized new runway construction plans in a report as being "misleadingly optimistic." The demand to fly in Europe is forecast to triple by 2030, to the dismay of environmental groups campaigning against air pollution, noise pollution and increased greenhouse gas emissions.

Airline sales in Asia are escalating as well, and the skies are becoming increasingly more crowded. In China alone, the market is projected to grow more than 200 percent from 1999 to 2014. Meanwhile, precise guidelines on international aircraft emissions are excluded from the Kyoto Protocol, with the stipulation that airline emission reform must be taken up by a separate organization, the International Civil Aviation Organization (ICAO). Internationally, fuel used for aviation is tax exempt, and according to ICAO Secretariat John Crayston, "While the ICAO has established emissions standards for certain emissions there are no standards for CO2." The International Air Transport Association (IATA) estimates that aviation's share in climate change is at about 3.5 percent of the total contributions, which is predicted to climb to five percent by 2050.

According to the International Panel on Climate Change (IPCC), aerosol particles that are emitted in aviation such as soot, metals and sulfuric acid can indirectly influence climate change by causing additional cirrus clouds to form, which in turn trap the heat rising from the Earth's surface. The IPCC projects an overall global temperature increase from 34.7 to 40.1 degrees Fahrenheit between 1990 and 2100.

Friends of the Earth London recommends that European travelers opt for high-speed rail instead of flying, especially when going a relatively short distance. According to Climate Action Network Europe, the same passenger traveling from Amsterdam to London would be responsible for emitting 2.8 ounces of CO2 per mile if traveling by rail, 7.7 ounces if driving a typical automobile, and 9.5 ounces if traveling by plane--in other words, a frequent flyer could cut his or her CO2 emissions more than 300 percent by simply opting to take the rail.

In the U.S., however, there aren't as many greener options for travelers. The kind of high-speed rail system that traverses Europe just doesn't exist in the U.S. And since demand only seems to be growing, the change may have to take place in the technology of the airplanes themselves. A number of measures have been proposed to try and protect the climate from further change and to reduce the harmful effects of this soaring boom in aviation.

European environmental groups such as Friends of the Earth, Airport-Watch and Climate Action Network Europe are pushing for the imposition of sales taxes on airline flights, and calling for an end to the airline industry's fuel tax exemption. The sales tax could prompt travelers to look for cheaper (and greener) methods of travel. And yet, these taxes could prove to be a competitive issue within the European Union, possibly resulting in consumers crossing national borders to avoid them.

The IATA maintains that taxing airlines in the U.S., especially after the billions in monetary losses after September 11, would only hinder the growth of new alternatives that the airlines are working toward. "Generally speaking, if you tax the airlines you're removing our ability to reinvest in new technology," says an IATA spokesperson. "Airlines use their monetary surpluses to re-invest in low-emission, fuel-efficient technology."

Programs are in place internationally to help airlines decrease their fuel consumption while cutting their total expenditures. Flight Sciences International, for instance, has worked with carriers like British Airways, SwissAir and Austrian Airlines to help conserve fuel. According to the IATA Environmental Department, emissions of CO2 and water vapor are directly proportional to the fuel burned.

Of course, the relative pollution of airplanes versus automobiles, buses or trains is related to the planes' passenger load: When traveling at least 75 percent full, Boeing claims, airliners have lower per-passenger-mile emissions than a car carrying a driver and a single passenger.

Some environmentalists point out that fuel-efficiency and emissions standards could be tightened while requiring airlines to set aside a certain amount of their profits for efficient technology.

The low-cost ticket blitz threatens to push the Earth's atmospheric conditions into the danger zone. While fares may be low for today's global travelers, the future costs for the environment may be immeasurable. CONTACT: Bluewater Network, [phone], www.bluewaternetwork.org; IATA Environmental Department, www.iata. org/whatwedo/environment/index.