The reality of climate change demands action by all contributing sectors.  Although aviation is a small contributor at present, the demand projections for air transport mean a growing relative share of total emissions.  The IPCC undertook a comprehensive assessment of the effects of aviation on the global climate in 1999 and updating work has been undertaken since in Europe and elsewhere. Governments have grasped the need for firm action, nowhere more so than the UK which has defined CO2 control targets, developed wide-ranging strategies and taken a leading role in the international climate debate.

Some things are clear: the CO2 contribution from aviation to climate change can be identified with confidence, leading to an increasing drive across the aviation sector to improve efficiency. However, the nature and severity of response action will be influenced by the longer-term projections for total climate change. Apart from its CO2 effects, aviation emissions have climate effects through emissions of oxides of nitrogen (NOx) and through contrail induced cirrus clouds. Whilst knowledge is improving quickly in these areas of science, uncertainty remains about the combined effect of all these emissions owing to the complexity of climate physics and chemistry. UK academia is at the forefront of work to give the Government and others the knowledge and confidence needed to implement effective measures.

Omega partners are addressing the main open questions on aviation climate science.  Non-CO2 impacts are the main focus with studies on contrail formation and on modelling the resultant impacts. We are defining a roadmap for knowledge steps to achieve certainty on the totality of aircraft effects. Having confidence in the future projections for the sector needs both sound metrics for calculating integrated effects and feeding growth scenarios through to global temperature change assessments. Omega is also addressing these issues.

An important part of using the science effectively is to relate it to the potential solutions. Omega is linking aero-technology modelling and climate effects modelling to understand the emissions relationships better and is feeding science knowledge into work to analyse the potential of operational and market solutions.

These activities, being carried forward with key government and industry players and with the international science community, will lead to further directed studies that track down and answer the remaining uncertainties.