http://www.biologicaldiversity.org/prog ... index.html
Aircraft emit staggering amounts of CO2, the most prevalent manmade greenhouse gas. In fact, they currently account for 12 percent of CO2 emissions from U.S. transportation sources and 3 percent of the United States’ total CO2 emissions. All told, the United States is responsible for nearly half of worldwide CO2 emissions from aircraft.
In addition to CO2, aircraft emit nitrogen oxides, known as NOx, which contribute to the formation of ozone, another greenhouse gas. Emissions of NOx at high altitudes result in greater concentrations of ozone than ground-level emissions. Aircraft also emit water vapor at high altitudes, creating condensation trails or “contrails,” visible cloud lines that form in cold, humid atmospheres and contribute to the warming impacts of aircraft emissions. The persistent formation of contrails is associated with increased cirrus cloud cover, which also warms the Earth’s surface. All told, aircraft’s high-altitude emissions have a greater global warming impact than they would if the emissions were released at ground level.
Alarmingly, aircraft emissions are expected to more than triple by mid-century. But the Center is working to make sure that prediction doesn’t come true: In December 2007, we joined with states, regional governments, and other conservation groups to petition the U.S. Environmental Protection Agency to address the effects of aircraft pollution under the Clean Air Act. The agency continued to drag its feet on the issue, so in July 2008 the Center and allies filed a notice of intent to sue the agency for its failure to address global warming pollution from both ships and aircraft.
It’s crucial that the Environmental Protection Agency and air industry do their part to fight global warming. This means adopting operational measures to minimize fuel use and reduce emissions from aircraft; requiring the use of lighter, more efficient airplanes; and producing and using cleaner jet fuels.
A more in-depth essay on the subject;
So how is it that;
this has never been addressed?
There are absolutely no emission controls on aircraft.
The Expanded Scope of Policy-making
In the past, ICAO's policy-making to address the environmental impact of aircraft engine emissions focused primarily on the ground level effects. In recent years, the scope has been expanded to include the global impact of aircraft engine emissions.
In this regard, the Kyoto Protocol (pdf) (1997) to the United Nations Framework Convention on Climate Change (UNFCCC) is of particular importance. The Protocol, which entered into force on 16 February 2005, requires countries listed in Annex I to the Convention (industrialized countries) to reduce their collective emissions of six greenhouse gases, the one most relevant to aviation being carbon dioxide (CO2). International aviation emissions are currently excluded from the targets. Instead, Article 2, paragraph 2 of the Kyoto Protocol states that the responsibility for limiting or reducing greenhouse gas emissions from aviation bunker fuels shall fall to the Annex I Parties, working through ICAO.
In 2007, the ICAO Assembly requested the Council (Assembly Resolution A36-22 (pdf), Appendix K) to continue to study policy options to limit or reduce the environmental impact of aircraft engine emissions and to develop concrete proposals and provide advice as soon as possible to the Conference of the Parties to the UNFCCC. It called for special emphasis to be placed on the use of technical solutions while continuing consideration of market-based measures, and taking into account potential implications for developing as well as developed countries.
The "rational argument" is that aircraft overall use less fuel than having each person drive a car.
However, the entire issue of emissions is thus overlooked!
Cars have emission controls, aircraft do not. With the argument; no one drives a car across the ocean, nor would they even consider most travel if they had to drive there.
Most importantly, aircraft emit high levels of NO2 that cars do not, directly into the upper atmosphere where they affect ozone levels the greatest.
To be green is definitely not to fly.
I will address boats in another thread.