Pollution from airplanes cruising high in the atmosphere adds to global warming, and the aviation industry's contribution is expected to increase significantly over the next five decades, according to a report issued late last night by the UN's Intergovernmental Panel on Climate Change (IPCC). The report is the first analysis of an individual industry by the IPCC, which was established in 1988 to provide the world's governments with assessments of the threat of climate change.
"Airplanes could become as big a source of global-warming pollution relative to other sources as cars are today. The aviation industry needs to take responsibility for its emissions and work to produce a cleaner airplane," said Dr. Michael Oppenheimer, chief scientist of EDF and co-developer of two of the emissions scenarios explored in the IPCC report.
Carbon dioxide, oxides of nitrogen, particulates, and water vapor from the exhaust of airplanes contribute directly and indirectly to global warming. The report presents scenarios for growth in aviation emissions based on models of the industry developed independently by the International Civil Aviation Organization, a UN agency, and the Environmental Defense Fund (EDF). The report notes aviation has been growing about two and a half times faster than the world's economy as a whole since 1960, and that future growth in air traffic is expected to far outstrip the industry's most optimistic projections for future efficiency gains, leading to substantial growth in emissions. In one IPCC scenario, aviation would produce roughly 15% of the climate-changing effect of all human-caused greenhouse gas emissions by 2050, other scenarios have lower, but still significant impacts.
Greenhouse gases like carbon dioxide will become subject to binding international limits under the Kyoto Protocol to the UN Framework Convention on Climate Change. But pollution from planes in international travel is temporarily exempted from these restrictions and aviation industry groups have been pressing to avoid any future limitations.
This year, the Clinton Administration proposed significant reductions in the funding for scientific research on the atmospheric effects of aviation and the total elimination of funding for research on the effects of supersonic aircraft.
"In the face of this compelling new evidence that aircraft present a growing threat to the global environment, we hope the administration reverses its stance on basic research in this area. Otherwise we will be literally flying blind into a perilous future," said Oppenheimer.