The application of drug trials methodology points the way to understanding aviation and climate change
Dr Kenji Takeda (right) receives the Royal Aeronautical Society's Written Paper Prize Silver Award from RAeS President, Dr Michael Steeden
Tue 21 July 2009 – Academics from the UK’s University of Southampton have undertaken a major review of the impact of aviation on climate change by uniquely applying systematic review methodology for drug appraisals to the subject. The study, a collaboration between the university’s Schools of Engineering Sciences and Medicine, has just been awarded the Royal Aeronautical Society Silver Medal for 2009. By adapting replicable and transparent methods from the field of evidence-based medicine, the authors have calculated from existing data the lower and upper bounds for estimates of the effect of aviation on climate change in an objective manner.
The paper, entitled ‘Systematic review of the impact of emissions from aviation on current and future climate’, is the first major study of its kind in the last decade, claim the authors, since the Intergovernmental Panel on Climate Change (IPCC) published its findings on this subject in 1999.
Results of the paper show that there is a wide range of predictions for the impact of aviation on climate and these are most dependent on assumptions made about future social and economic growth. The paper also highlights the dependency on the level of scientific understanding and modelling capability, particularly around the non-CO2 effects of aircraft.
In their abstract, the authors’ estimates for the future contribution of aviation to global radiative forcing in 2015 range from 5.31% to 8.04%. For 2050, the estimates have a wider spread, from 2.12% to 17.33%, the latter being for the most extreme technology and growth scenario. They caution that global estimates should be considered within the context of uncertainties in accounting for the direct and indirect effects of different contributions.
Variations between lower and upper bounds for estimates of radiative forcing are relatively low for carbon dioxide, around 131% to 800% for cirrus clouds effects, and 1044% for soot. Advances in climate research, particularly in the area of contrail and cloud effects, have led to some revision of the 1999 IPCC estimates, and demonstrates that the research community is actively working to further understand the underlying science.
Dr Kenji Takeda, Senior Lecturer in the School of Engineering Sciences and lead author of the paper, said: “By using an objective approach to reviewing the effect of aircraft on climate, we hope to provide a good baseline for this active debate. There is a clear need for improving scientific understanding, and it is vital for the aircraft industry to continue to support climate scientists to work towards future solutions for sustainable aviation.”
Systematic reviews are used extensively for assessing the effectiveness of methods for preventing, treating and managing different diseases and to inform national policy in the UK. This is one of the first times this rigorous approach has been applied to the complex issues around climate change.
The work was part-funded by Greener by Design, a UK initiative that brings together experts from the aviation industry with government bodies and research institutions to seek practical and sustainable solutions to the challenge posed by aviation’s impact on the environment.
The university is also home to the Institute of Sound and Vibration Research which has carried out studies into the environmental impact of aircraft noise.