The air pollution are both global and local. Overall, aircraft emissions contribute to the increase of the greenhouse effect and therefore to global warming. Locally, the rotation of aircraft at airports causes noise and contributes to air pollution. Low – level military aircraft flights are also a source of noise pollution.
Locally, the pollutants concerned are in particular nitrogen oxides (NOx), sulfur dioxide (SO2), ozone (O3), a secondary pollutant, and the particles resulting from the combustion of kerosene. These compounds have a negative influence on human, animal and plant health.
Given the considerable increase in air traffic and the pressure of people suffering nuisances (often through neighborhood associations), the aviation industry is developing quieter and more fuel- efficient engines, but these advances are partly canceled by the strong and steady increase of traffic. For their part, the authorities are developing and applying “continuous descent” rather than stepped approach techniques, aircraft interception altitude readjustments by automatic landing systems, and optimizing departure trajectories. as of arrival.
Finally, the administrations regulate the use of airspace in order to protect the economic interests of the regions concerned, the employment and the interests of the residents of airports.
International regulation of air travel GHG emissions
Kyoto Protocol 2005
Greenhouse gas emissions from fuel consumption in international aviation, in contrast to those from domestic aviation and from energy use by airports, are excluded from the scope of the first period (2008–2012) of the Kyoto Protocol, as are the non-CO2 climate effects. Instead, governments agreed to work through the International Civil Aviation Organization (ICAO) to limit or reduce emissions and to find a solution to the allocation of emissions from international aviation in time for the second period of the Kyoto Protocol starting from 2009; however, the Copenhagen climate conference failed to reach an agreement.
Recent research points to this failure as a substantial obstacle to global policy including a CO2 emissions reduction pathway that would avoid dangerous climate change by keeping the increase in the average global temperature below a 2 °C rise.
Approaches toward emissions trading
As part of that process the ICAO has endorsed the adoption of an open emissions trading system to meet CO2 emissions reduction objectives. Guidelines for the adoption and implementation of a global scheme are currently being developed, and will be presented to the ICAO Assembly in 2007, although the prospects of a comprehensive inter-governmental agreement on the adoption of such a scheme are uncertain.
Within the European Union, however, the European Commission has resolved to incorporate aviation in the European Union Emissions Trading Scheme (ETS). A new directive was adopted by the European Parliament in July 2008 and approved by the Council in October 2008. It became effective on 1 January 2012.
Researchers at the Overseas Development Institute investigated the possible effects on Small Island Developing States (SIDS) of the European Union’s decision to limit the supply of Certified Emission Reductions (CERs) to its ETS market to Least Developed Countries (LDCs) from 2013. Most SIDS are highly vulnerable to the effects of climate change and rely heavily on tourism as a basis for their economies, so this decision could place them at some disadvantage. The researchers therefore highlight the need to ensure that any regulatory frameworks put in place to tackle climate change take into account the development needs of the most vulnerable countries affected.
A report published by researchers at the Centre for Aviation, Transport and Environment at Manchester Metropolitan University found that the only way to have a significant impact on emissions was to put a price on carbon and to use a market-based measure (MBM), such as the EU Emissions Trading Scheme (ETS).
International Civil Aviation Organization agreement 2016
In October 2016 the UN agency International Civil Aviation Organization (ICAO) finalized an agreement among its 191 member nations to address the more than 458 Mt (2010) of carbon dioxide emitted annually by international passenger and cargo flights. The agreement will use an offsetting scheme called CORSIA (the Carbon Offsetting and Reduction Scheme for International Aviation) under which forestry and other carbon-reducing activities are directly funded, amounting to about 2% of annual revenues for the sector. Rules against ‘double counting’ should ensure that existing forest protection efforts are not recycled. The scheme does not take effect until 2021 and will be voluntary until 2027, but many countries, including the US and China, have promised to begin at its 2020 inception date. Under the agreement, the global aviation emissions target is an 80% reduction by 2035 relative to 2020. NGO reaction to the deal was mixed.
The agreement has critics. It is not aligned with the 2015 Paris climate agreement, which set the objective of restricting global warming to 1.5 to 2°C. A late draft of the agreement would have required the air transport industry to assess its share of global carbon budgeting to meet that objective, but the text was removed in the agreed version. CORSIA will regulate only about 25 percent of aviation’s international emissions, since it grandfather’s all emissions below the 2020 level, allowing unregulated growth until then. Only 65 nations will participate in the initial voluntary period, not including significant emitters Russia, India and perhaps Brazil. The agreement does not cover domestic emissions, which are 40% of the global industry’s overall emissions. One observer of the ICAO convention made this summary, “Airline claims that flying will now be green are a myth. Taking a plane is the fastest and cheapest way to fry the planet and this deal won’t reduce demand for jet fuel one drop. Instead offsetting aims to cut emissions in other industries,…” Another critic called it “a timid step in the right direction.”
In Europe, the Community system of exchange of emission allowances (EU ETS) applies since 2012 in the emissions of CO2Civil Aviation pursuant to Directive 2008/101 / EC of 19 November 2008. However, faced with the challenge of twenty-six states outside the European Union, the European Commission proposed inNovember 2012 postpone the application of the regime to flights to and from the European Economic Area (EEA) until a global solution is found under the aegis of ICAO. However, the Directive has continued to apply to all flights within and between the 31 European countries applying the EU ETS.
Technical solutions to improve efficiency
While it is true that late model jet aircraft are significantly more fuel efficient (and thus emit less CO2 in particular) than the earliest jet airliners, new airliner models in the 2000s were barely more efficient on a seat-mile basis than the latest piston-powered airliners of the late 1950s (e.g. Constellation L-1649-A and DC-7C). Claims for a high gain in efficiency for airliners over recent decades (while true in part) has been biased high in most studies, by using the early inefficient models of jet airliners as a baseline. Those aircraft were optimized for increased revenue, including increased speed and cruising altitude, and were quite fuel inefficient in comparison to their piston-powered forerunners.
Today, turboprop aircraft – probably in part because of their lower cruising speeds and altitudes (similar to the earlier piston-powered airliners) compared to jet airliners – play an obvious role in the overall fuel efficiency of major airlines that have regional carrier subsidiaries. For example, although Alaska Airlines scored at the top of a 2011–2012 fuel efficiency ranking, if its large regional carrier – turbo-prop equipped Horizon Air – were dropped from the lumped-in consideration, the airline’s ranking would be somewhat lower, as noted in the ranking study.
Aircraft manufacturers are striving for reductions in both CO2 and NOx emissions with each new generation of design of aircraft and engine. While the introduction of more modern aircraft represents an opportunity to reduce emissions per passenger kilometre flown, aircraft are major investments that endure for many decades, and replacement of the international fleet is therefore a long-term proposition which will greatly delay realizing the climate benefits of many kinds of improvements. Engines can be changed at some point, but nevertheless airframes have a long life. Moreover, rather than being linear from one year to the next the improvements to efficiency tend to diminish over time, as reflected in the histories of both piston and jet powered aircraft.
A 2014 life-cycle assessment of the cradle-to-grave reduction in CO2 by a carbon-fiber-reinforced polymer (CFRP) airliner such as a Boeing 787 – including its manufacture, operations and eventual disposal – has shown that by 2050 such aircraft could reduce the airline industry’s CO2 emissions by 14–15%, compared use of conventional airliners. The benefit of CFRP technology is not higher than that amount of reduction, despite the lighter weight and substantially lower fuel consumption of such aircraft, “because of the limited fleet penetration by 2050 and the increased demand for air travel due to lower operating costs.”
Research projects such as Boeing’s ecoDemonstrator program have sought to identify ways of improving the efficiency of commercial aircraft operations. The U.S. government has encouraged such research through grant programs, including the FAA’s Continuous Lower Energy, Emissions and Noise (CLEEN) program, and NASA’s Environmentally Responsible Aviation (ERA) Project.
Adding an electric drive to the airplane’s nose wheel may improve fuel efficiency during ground handling. This addition would allow taxiing without the use of the main engines.
Another proposed change is the integrating of an Electromagnetic Aircraft Launch System to the airstrips of airports. Some companies such as Airbus are currently researching this possibility. The adding of EMALS would allow the civilian aircraft to use considerably less fuel (as a lot of fuel is used during take off, in comparison to cruising, when calculated per km flown). The idea is to have the aircraft take off at regular aircraft speed, and only use the catapult for take-off, not for landing.
Other opportunities arise from the optimization of airline timetables, route networks and flight frequencies to increase load factors (minimize the number of empty seats flown), together with the optimization of airspace. However, these are each one-time gains, and as these opportunities are successively fulfilled, diminishing returns can be expected from the remaining opportunities.
Another possible reduction of the climate-change impact is the limitation of cruise altitude of aircraft. This would lead to a significant reduction in high-altitude contrails for a marginal trade-off of increased flight time and an estimated 4% increase in CO2 emissions. Drawbacks of this solution include very limited airspace capacity to do this, especially in Europe and North America and increased fuel burn because jet aircraft are less efficient at lower cruise altitudes.
While they are not suitable for long-haul or transoceanic flights, turboprop aircraft used for commuter flights bring two significant benefits: they often burn considerably less fuel per passenger mile, and they typically fly at lower altitudes, well inside the tropopause, where there are no concerns about ozone or contrail production.
Some scientists and companies such as GE Aviation and Virgin Fuels are researching biofuel technology for use in jet aircraft. Some aircraft engines, like the Wilksch WAM120 can (being a 2-stroke Diesel engine) run on straight vegetable oil. Also, a number of Lycoming engines run well on ethanol.
In addition, there are also several tests done combining regular petrofuels with a biofuel. For example, as part of this test Virgin Atlantic Airways flew a Boeing 747 from London Heathrow Airport to Amsterdam Schiphol Airport on 24 February 2008, with one engine burning a combination of coconut oil and babassu oil. Greenpeace’s chief scientist Doug Parr said that the flight was “high-altitude greenwash” and that producing organic oils to make biofuel could lead to deforestation and a large increase in greenhouse gas emissions. Also, the majority of the world’s aircraft are not large jetliners but smaller piston aircraft, and with major modifications many are capable of using ethanol as a fuel. Another consideration is the vast amount of land that would be necessary to provide the biomass feedstock needed to support the needs of aviation, both civil and military.
In December 2008, an Air New Zealand jet completed the world’s first commercial aviation test flight partially using jatropha-based fuel. Jatropha, used for biodiesel, can thrive on marginal agricultural land where many trees and crops won’t grow, or would produce only slow growth yields. Air New Zealand set several general sustainability criteria for its Jatropha, saying that such biofuels must not compete with food resources, that they must be as good as traditional jet fuels, and that they should be cost competitive with existing fuels.
In January 2009, Continental Airlines used a sustainable biofuel to power a commercial aircraft for the first time in North America. This marks the first sustainable biofuel demonstration flight by a commercial carrier using a twin-engined aircraft, a Boeing 737-800, powered by CFM International CFM56-7B engines. The biofuel blend included components derived from algae and jatropha plants.
One fuel biofuel alternative to avgas that is under development is Swift Fuel. Swift fuel was approved as a test fuel by ASTM International in December 2009, allowing the company to continue their research and to pursue certification testing. Mary Rusek, president and co-owner of Swift Enterprises predicted at that time that “100SF will be comparably priced, environmentally friendlier and more fuel-efficient than other general aviation fuels on the market”.
As of June 2011, revised international aviation fuel standards officially allow commercial airlines to blend conventional jet fuel with up to 50 percent biofuels. The renewable fuels “can be blended with conventional commercial and military jet fuel through requirements in the newly issued edition of ASTM D7566, Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons”.
In December 2011, the FAA announced it is awarding $7.7 million to eight companies to advance the development of drop-in commercial aviation biofuels, with a special focus on ATJ (alcohol to jet) fuel. As part of its CAAFI (Commercial Aviation Alternative Fuel Initiative) and CLEEN (Continuous Lower Emissions, Energy and Noise) programs, the FAA plans to assist in the development of a sustainable fuel (from alcohols, sugars, biomass, and organic matter such as pyrolysis oils) that can be “dropped in” to aircraft without changing current infrastructure. The grant will also be used to research how the fuels affect engine durability and quality control standards.
Finally, liquified natural gas is another fuel that is used in some airplanes. Besides the lower GHG emissions (depending from where the natural gas was obtained from), another major benefit to airplane operators is the price, which is far lower than the price for jet fuel.
Reducing air travel
Personal choices and social pressure
The German video short The Bill explores how travel and its impacts are commonly viewed in everyday developed-world life, and the social pressures that are at play. British writer George Marshall has investigated common rationalizations that act as barriers to making personal choices to travel less, or to justify recent trips. In an informal research project, “one you are welcome to join”, he says, he deliberately steered conversations with people who are attuned to climate change problems to questions about recent long-distance flights and why the travel was justified. Reflecting on actions contrary to their beliefs, he noted, “(i)ntriguing as their dissonance may be, what is especially revealing is that every one of these people has a career that is predicated on the assumption that information is sufficient to generate change – an assumption that a moment’s introspection would show them was deeply flawed.”
Business and professional choices
With most international conferences having hundreds if not thousands of participants, and the bulk of these usually traveling by plane, conference travel is an area where significant reductions in air-travel-related GHG emissions could be made….This does not mean non-attendance.
For example, by 2003 Access Grid technology has already been successfully used to host several international conferences, and technology has likely progressed substantially since then. The Tyndall Centre for Climate Change Research has been systematically studying means to change common institutional and professional practices that have led to large carbon footprints of travel by research scientists, and issued a report.
Ending incentives to fly—frequent flyer programs
Over 130 airlines have “frequent flyer programs” based at least in part on miles, kilometers, points or segments for flights taken. Globally, such programs included about 163 million people as reported in 2006. These programs benefit airlines by habituating people to air travel and, through the mechanics of partnerships with credit card companies and other businesses, in which high profit margin revenue streams can amount to selling free seats for a high price. The only part of United Airlines business that was making money when the company filed for bankruptcy in 2002 was its frequent flyer program.
Concerning business travel, “The ease of international air travel and the fact that, for most of us, the costs are met by our employers, means that… globe trotting conference travel is often regarded as a perk of the job.” However, the perk usually is not only the business trip itself, but also the frequent flyer points which the individual accrues by taking the trip, and which can be redeemed later for personal air travel. Thus a conflict of interest is established, whereby bottom-up pressure may be created within a firm or government agency for travel that is really not necessary. Even when such conflict is not a motivation, the perk of frequent flyer miles can be expected to lead in many cases to personal trips that would not be taken if a ticket had to be paid for with personal funds.
By just using an airline-sponsored credit card to pay one’s household expenses, personal or business bills, or even expense bills charged to an employer, frequent flyer points can be racked up quickly. Thus, free travel—for which the individual has to pay nothing extra—becomes a reality. Across society, this too can be expected to lead to much air travel—and greenhouse gas emissions—that otherwise would not occur.
Several studies have contemplated the elimination of frequent flyer programmes (FFPs), on the grounds of anti-competitiveness, ethics, conflict with society’s overall well-being, or climate effects. There is a record of governments disallowing or banning FFPs and of industry players requesting bans. Denmark did not allow the programs until 1992, then changing its policy because its airlines were disadvantaged. In 2002, Norway banned domestic FFPs in order to promote competition among its airlines. In the U.S. in 1989, a vice president of Braniff “said the government should consider ordering an end to frequent-flyer programs, which he said allow unfair competition.”
A Canadian study said that because of competition no airline could unilaterally end its FFP, but that a national government could use its regulatory power to end the programs broadly, which in Canada’s case would also require North America-wide cooperation. In further analysis, a Scandinavian study which recommended an end to frequent flyer plans said, “the only possible way of prohibiting FFPs successfully now that they have spread from the US to Europe to the Far East would be to do so on a global basis. The basis exists: it could be done by the World Trade Organization.” A recent study which surveyed frequent flyers in the U.K. and Norway, looked into behavioral addition to frequent flying and the “flyer’s dilemma” of the conflict between “the social and personal benefits of flying and air travel’s impact on climate change.” It concluded that:
Continued growth in both frequent flying practices and concern over air travel’s climate impacts are in a dynamic relationship and the question of whether one or the other will reach a tipping point cannot yet be determined. Self-regulation, external regulation, social norms, technology and physical resources will continue to co-constitute the balance. An increasing stigmatisation of ‘excessive’ air travel may (re)frame flying as more open to collective external mitigation.
This means government action.
Potential for governmental constraints on demand
One means for reducing the environmental impact of aviation is to constrain demand for air travel, through increased fares in place of expanded airport capacity. Several studies have explored this:
The UK study Predict and Decide – Aviation, climate change and UK policy, notes that a 10% increase in fares generates a 5% to 15% reduction in demand, and recommends that the British government should manage demand rather than provide for it. This would be accomplished via a strategy that presumes “… against the expansion of UK airport capacity” and constrains demand by the use of economic instruments to price air travel less attractively.
A study published by the campaign group Aviation Environment Federation (AEF) concludes that by levying £9 billion of additional taxes, the annual rate of growth in demand in the UK for air travel would be reduced to 2%.
The ninth report of the House of Commons Environmental Audit Select Committee, published in July 2006, recommends that the British government rethink its airport expansion policy and considers ways, particularly via increased taxation, in which future demand can be managed in line with industry performance in achieving fuel efficiencies, so that emissions are not allowed to increase in absolute terms.
Source from Wikipedia