Pew report finds reductions in aviation GHG emissions over business-as-usual projections could be halved
Could the blended wing body aircraft design being developed by NASA and Boeing bring substantial GHG savings in the future? (photo: NASA)
Mon 18 Jan 2010 – Under business-as-usual (BAU) forecasts, CO2 emissions from global aviation are estimated to grow 3.1% per year over the next 40 years, resulting in a 300% increase in emissions by 2050 compared to 2007. However, a new report published by the Pew Center on Global Climate Change finds that reductions of more than 50% below the projected levels are possible. The report, which looks at both the aviation and marine transportation sectors, presents a range of near, medium and long term mitigation options. For the near to medium term (to 2025), improvements in operational efficiency – for example advanced navigation and air traffic management systems for aviation – have the potential to reduce GHG emissions by about 5% below BAU projections, with advanced propulsion systems and new airframe designs further reducing emissions by up to 35% over the longer term (to 2050).
Reducing the carbon intensity of the energy sources used in aviation and marine transportation by transitioning to alternative fuels could also reduce emissions over the medium term, although the level of potential reductions is uncertain, say the report’s authors David McCollum and Gregory Gould of the University of California at Davis and David Greene from Oak Ridge National Laboratory.
“While numerous technical challenges still exist, the main challenge to the use of alternative fuels will be the ability of aviation and shipping to compete with other transportation subsectors for a potentially limited supply of low-carbon biofuels,” they suggest. “This could particularly be an issue with marine shipping, where the industry currently consumes the lowest-cost fuels available, namely residual fuel oil.”
The report presents an introduction to aviation and marine transportation and a discussion of the determinants of GHG emissions from transportation; provides an overview of the current emissions, trends and growth projections; explains the technological mitigation options and potential GHG emission reductions; and discusses policy options at both the domestic and international level to achieve deep and durable reductions in emissions.
Beyond technical measures, reducing the demand for aviation and shipping could achieve GHG reductions, though the potential impacts are probably limited, says the report. “The challenge for these subsectors is that there are few suitable alternatives for the services provided by aviation and marine shipping. High-speed rail could replace some passenger air travel, but currently there are few alternatives to marine shipping.
“With only modest cost increases likely to be achievable through policy intervention,and a limited number of alternatives, a large reduction in demand compared to BAU seems unlikely from these subsectors,” it concludes.
Aviation and marine transportation combined are responsible for around 5% of total GHG emissions in the United States and 3% globally, say the authors.
Commenting on the findings, Eileen Claussen, President of the Pew Center and former US Assistant Secretary of State for Oceans and International Environmental and Scientific Affairs, said: “Aviation and marine shipping are two of the fastest growing modes of transportation. Their greenhouse gas emissions are growing rapidly as well. To protect the climate, we need to reduce emissions across the entire economy. Aviation and marine shipping are part of the climate problem, and this report shows that they can be part of the solution.”
