The Rising Effect of Aviation on Climate: Global temperature change implications of projections of aviation growth in the context of GHG emission mitigation scenarios.
Omega: Higher Education Funding Council for England (HEFCE)
2008 – 2009
International commitments to limit greenhouse gas emissions, made under the first commitment period of the Kyoto Protocol (2008 – 2012) exclude emissions from international transport. However, showing an increase of 42% between 1990 and 2005. In addition, the effect of non-CO2 aviation emissions on climate is complex, with high-altitude NOx emissions inducing tropospheric ozone formation and reducing the atmospheric lifetime of methane, while particles and water vapour lead to the formation of linear contrails and cirrus clouds under certain conditions. Based on current knowledge, our analysis suggests that from 1940 to 2005 worldwide aviation prouced a rise in global mean temperatures of 0.028 °C (68% range 0.023-0.050). This represents 4.7% (4.0-5.2%) of the total anthropogenic change. The total influence of aviation on climate is, therefore expected to be considerably greater than is suggested solely on the basis of its share of current anthropogenic fossil CO2 emissions.
Aviation is currently a small part of the human activities that affect the earth’s climate. But given the industry’s growth, its effects on the global climate may also steadily increase. It is suggested that global greenhouse gas emissions need to be approximately halved by 2050 relative to 1990 in order to keep the global mean temperature increase below 2ºC
This poses immense challenges for all regions and sectors, including aviation. Climate change is and will be a key driver for policies and investments in the aviation sector. Quantifying the global temperature implications of various aviation growth scenarios is therefore vital for informed decision-making – especially given the present deep concerns over climate change. This project will compile future scenarios of aviation from the research literature and information from industry and governmental stakeholders. Hypothetical factors around aviation growth, alternative fuels and radical aircraft design will also be incorporated.
Scenarios will be interpreted in terms of greenhouse gas emissions and other effects on the atmosphere such as aircraft contrails.
The study will assess these aviation projections in the light of various climate mitigation scenarios, including stabilization scenarios and those compatible with the EU’s 2ºC climate change target. Various time horizons will be considered including 2020, 2030, 2050 and possibly beyond. The project will provide likely temperature projections and
their medians for each aviation growth scenario.
Since 1940, the aviation share of global fossil Co2 emissions has risen to 2005 value of about 2.8. based on our combination of Revenue Passenger kilometers, energy demand and jet fuel energy content. In comparison, the relative share of UK emsissions has declined to around 2.0%. Cumulative fossil Co2 emissions for aviation are about 56% those of the UK since 1940 (compare areas under curves). For our background data set, we take into account global anthropogenic emissions histories of 19 greenhouse gases, aerosols and precursos gases in addition to 16 substances controlled under the montreal protocol.
Researchers used the MAGICC model (Model for the Assessment of Greenhouse-gas Induced Climate Change), the simple climate model used by the Intergovernmental
Panel on Climate Change for multiple scenario analysis, in order to assess the climate implications of potential aviation growth.
This study will provide the scientific community with a new set of aviation growth scenarios and associated global temperature implications. Governmental authorities and
industry stakeholders will get an assessment of aviation growth scenarios and their impact on climate change. This will enable informed decision-making, both in terms of policies (such as inclusion of the aviation sector in an emissions trading scheme) and industry investment. Information will be available on the impact of aviation relative to the total human-induced effects on climate change.