Future technology improvements will help reduce aviation emissions but not by enough, finds US GAO report
Wed 10 Jun 2009 – Following a congressional request, the US Government Accountability Office (GAO) has produced a 100-page report, ‘Aviation and Climate Change’. It finds that even if many of the proposed low-carbon technologies were to be adopted by the aviation industry, it appears unlikely they would greatly reduce emissions by 2050, given the expected growth of commercial aviation as forecasted by the UN’s Intergovernmental Panel on Climate Change (IPCC). A number of policy options to address aircraft emissions are available to governments, including market-based measures such as cap-and-trade which, GAO believes, can be preferable as they would generally be more economically efficient.
The report looks in depth at IPCC estimates of aviation’s current and future contribution to greenhouse gas and other emissions that may affect climate change. It reviews existing and potential technological and operational improvements that can reduce aircraft emissions, and also policy options for government to help address commercial aircraft emissions.
It quotes IPCC figures that estimate global aviation currently accounts for about 2% of human-generated global CO2 emissions and about 3% of the potential warming effect of global greenhouse gas emissions that can affect the earth’s climate. By 2050, IPCC forecasts the share will have risen to 3% and 5% respectively, assuming emissions from other sectors also continue to grow. The report notes: “If other sectors make progress in reducing emissions and aviation emissions continue to grow, aviation’s relative contribution may be greater than IPCC estimated; on the other hand, if other sectors do not make progress, aviation’s relative contribution may be smaller than estimated.”
It says airlines currently rely on a range of technology improvements, such as fuel-efficient engines, to reduce emissions, although “some of which may have limited potential to generate future reductions”. According to experts consulted by GAO, a number of additional technological, operational and alternative fuel improvements are expected to help reduce aircraft emissions in the future.
“However, according to experts we interviewed,” says GAO, “some technologies, such as advanced airframes, have potential, but may be years away from being available, and developing and adopting them is likely to be costly. In addition, incentives for industry to research and adopt low-emissions technologies will be dependent to some extent on the level and stability of fuel prices. Finally, given expected growth of commercial aviation as forecasted by IPCC, even if many of these improvements are adopted, it appears unlikely they would greatly reduce emissions by 2050.”
Under its remit, the GAO does not make recommendations but details a number of policy options for consideration, including market-based measures, such as cap-and-trade or emissions taxes, and emissions standards for aircraft or engines. In addition, it says, government could increase government research and development to encourage development of low-emissions improvements.
The report devotes a whole section (Appendix I) to looking at the legal implications of including US carriers in the aviation European Union Emissions Trading Scheme, presenting US and international arguments for and against the inclusion.
In compiling the report, GAO conducted a literature review and interviewed representatives of government agencies (including FAA, NASA, EPA and ICAO), industry and environmental organizations, airlines and manufacturers, as well as international climate change and aviation experts.
According to its website, the US Government Accountability Office is known as “the investigative arm of Congress” and “the congressional watchdog”, supporting Congress in meeting its constitutional responsibilities.