AAJ | Climate Change


 Aircraft engines produce emissions that are similar to other emissions resulting from fossil fuel combustion. However, aircraft emissions are unusual in that a significant proportion is emitted at altitude. These emissions give rise to important environmental concerns regarding their global impact and their effect on local air quality at ground level. A comprehensive assessment concerning aviation’s contribution to global atmospheric problems is contained in the Special Report on Aviation and the Global Atmosphere, which was prepared at ICAO’s request by the Intergovernmental Panel on Climate Change (IPCC) in collaboration with the Scientific Assessment Panel to the Montreal Protocol on Substances that Deplete the Ozone Layer and was published in 1999. This told us inter alia:

  1. That aircraft emit gases and particles which alter the atmospheric concentration of greenhouse gases, trigger the formation of condensation trails and may increase cirrus cloudiness, all of which contribute to climate change; and
  1. That aircraft are estimated to contribute about 3.5 per cent of the total radiative forcing (a measure of change in climate) by all human activities and that this percentage, which excludes the effects of possible changes in cirrus clouds, was projected to grow.

 The new findings related to aviation emissions in IPCC AR4 are inter alia:

  • Due to developing scientific knowledge and more recent data estimates of the climate effects of contrails have been lowered and aircraft in 2005 are now estimated to contribute about 3.0 % of the total of the anthropogenic radiative forcing by all human activities.

  • Total CO2aviation emissions is approximately 2 % of the Global Greenhouse Emissions.

  • The amount of CO2emissions from aviation is expected to grow around 3-4 per cent per year; and

  • Medium-term mitigation for CO2emissions from the aviation sector can potentially come from improved fuel efficiency.

  • However, such improvements are expected to offset the growth of CO2 aviation emissions only partially.