The International Civil Aviation Organisation (ICAO) first became involved in emissions regulations in the early 1980s, when pressure began mounting to do something about pollution around airports.
This resulted in a set of standards, applied through engine certification, which are contained in Volume II of Annex 16 to the Chicago Convention on International Civil Aviation. The ruling established limits for NOx, carbon monoxide and unburned hydrocarbons from new engines during aircraft take-off and landing phases.
New impetus for extending the standard to cover atmospheric pollution during the cruise phase of flight followed the inclusion of ICAO in the Kyoto Protocol of 1997, which required nations to reduce their collective emissions of CO2, NOx and methane by about 5% between 2008-2012 compared with 1990.
The ICAO body charged with carrying out the necessary research and developing new aviation noise and emissions standards is the Committee on Aviation Environmental Protection (CAEP), which has been responsible for the work programmes leading to the current standards.
In 1993 ICAO, working on CAEP's recommendation and in response to increasing public pressure, tightened the original Annex 16 standards for NOx by 20%. In1995, the third meeting of CAEP (CAEP/3)recommended a further cut of 16%, but applying only to future production of current engine types after 2007. Although the scheme was seen as an important breakthrough, it was still rejected by some states, which were concerned that it would result in local operational restrictions and a consequent loss of aircraft values.
At its CAEP/4 meeting in 1998, the committee developed a modified standard calling for slightly less stringency on NOx - but only for engines with higher pressure ratios (which are those that produce the most NOx). Applicability of the standard was changed to apply to new engine designs only, from 2003. While not directly opposing this recommendation, member states expressed dissatisfaction with measures they considered too lenient.
Forging new standards
This is being addressed in the intense work programme leading to the planned CAEP/5 meeting, which is expected in January 2001.. Crucially, this meeting will set the agenda for ICAO's meeting in September 2001 where new emissions and noise standards will be forged.
CAEP's work now takes account of emissions of CO2 and other pollutants in the climb and cruise phases of flight, as well as aircraft productivity. It also includes studies of how improvements in air traffic management and other operations may affect pollution.
Controlling emissions through market-based options is becoming one of the main areas of interest to the regulators, and ICAO has been trying to achieve international consensus on how to proceed since 1996. One thing has become clear - that charges, not taxes, are the preferred option.
There are four main ways of applying charges: fuel levy, ticket levy, route levy and airport levy. Preliminary analysis shows that a route levy would be the most effective for global problems, while an airport levy would reduce emissions around airports. But CAEP says there remain "many practical problems" before any firm policy conclusions can be reached.
Increased emphasis is also being placed on emissions trading, which requires calculation and verification of aircraft emissions - something that aviation, by its nature, makes extremely difficult.
Source: Flight International
