|Total aviation carbon dioxide emissions resulting from six different scenarios for aircraft fuel use. Click to enlarge.
Carbon emissions from aviation could triple to 0.40 Gt carbon/year to account for 3% of the world’s anthropogenic carbon emissions by 2050 (relative to the mid-range IPCC emission scenario (IS92a)) according to the reference scenario in the latest climate change study by scientists at Manchester Metropolitan University (MMU) (UK). For the range of scenarios, the range of increase in carbon dioxide emissions from aviation to 2050 could be 1.6 to 10 times the value in 1992.
In 1992, air traffic contributed 2% of the then global anthropogenic carbon emissions, or 0.14 Gt carbon/year—about 13% of carbon dioxide emissions from all transportation sources.
Scientists at MMU’s Centre for Air Transport and the Environment calculated C02 emissions based on traffic predictions from sources including the International Civil Aviation Organization. The forecasts account for improvements in technology and air traffic management as total air traffic is predicted to increase by six to eight times 2000 levels by 2050.
Preliminary results will be presented to the Transport, Atmosphere and Climate conference jointly staged by CATE and the German Aerospace Center (DLR) at Oxford University on June 26-29.
This research confirms the message from the Aviation White Paper that the aviation sector is forecast to make up a considerable proportion of global emissions in the future. The results highlight that the rate of growth of aviation is far outstripping the rate of technological progress and improvements in efficiency.—David Lee, Professor of Atmospheric Science at MMU
New aircraft today are about 70% more fuel efficient per passenger-km than those built 40 years ago. The majority of this gain has been achieved through engine improvements and the remainder from airframe design improvement.
A further 20% improvement in fuel efficiency is expected by 2015 and a 40 to 50% improvement by 2050 relative to aircraft produced today.
The 2050 scenarios developed for this report already incorporate these fuel efficiency gains when estimating fuel use and emissions. Engine efficiency improvements reduce the specific fuel consumption and most types of emissions; however, contrails may increase and, without advances in combuster technology, NOx emissions may also increase.
The report notes that engine research programs are in progress with the goal of reducing Landing and Take-off cycle (LTO) emissions of NOx by up to 70% from today’s regulatory standards, while also improving engine fuel consumption by 8 to 10%, over the most recently produced engines, by about 2010.
There would not appear to be any practical alternatives to kerosene-based fuels for commercial jet aircraft for the next several decades.
The report also concludes that improvements in air traffic management (ATM) and other operational procedures could reduce aviation fuel burn by between 8 and 18%.
The results are part of an EC audit of emissions called QUANTIFY which is looking at the relative effects of different modes of transport—road, rail, air and sea—on the climate. The study also indicates that shipping could have a stronger effect than aviation from its CO2.