Abstract

The effects of aircraft emissions on the current and projected climate of our planet may be the most serious long-term environmental issue facing the aviation industry. Projections suggest that over the next several decades, the demand for aviation could grow to as much as three times its present level. This projected growth will likely result in higher aviation emissions and associated impacts on the environment, human health and welfare. However, there remain large uncertainties in our present understanding of the magnitude of climate impacts due to aviation emissions. With extensive growth in demand expected in aviation over the next few decades, it is imperative that timely action is taken to understand and quantify the potential impacts of aviation emissions to help policy makers address climate and other potential environmental impacts associated with aviation.

The climatic impacts of aviation emissions include the direct climate effects from carbon dioxide (CO2) and water vapor emissions, the indirect forcing on climate resulting from changes in the distributions and concentrations of ozone and methane as a consequence of aircraft nitrogen oxide (NOx) emissions, the direct effects (and indirect effects on clouds) from emitted aerosols and aerosol precursors, and the climate effects associated with contrails and cirrus cloud formation. To enable the development of the best strategy to mitigate these climatic impacts scientists must quantify these impacts and reduce current uncertainties to enable appropriate action. The only way to ensure that policymakers fully understand trade-offs from actions resulting from implementing engine and fuel technological advances, airspace operational management practices, and policy actions imposed by national and international bodies is to provide them with metrics that correctly capture the climate impacts of aviation emissions. This presentation is aimed at discussing the present state of knowledge of climatic impacts of aviation, examining the key underlying uncertainties and gaps in our scientific knowledge, and to identify and to make prioritized recommendations for the research necessary to resolve the important issues.

Biography

Donald (Don) J. Wuebbles is the Director of the School of Earth, Society, and Environment at the University of Illinois. He is also a Professor in the Department of Atmospheric Sciences as well as in the Department of Electrical and Computer Engineering. Dr. Wuebbles was Head of the Department of Atmospheric Sciences from 1994 until 2006 before accepting the new position. He earned his B.S. (1970) and M.S. (1972) degrees in Electrical Engineering from the University of Illinois. He received his Ph.D. in Atmospheric Sciences from the University of California at Davis in 1983. He is the author of over 380 scientific articles, most of which relate to atmospheric chemistry and global climate change as affected by both human activities and natural phenomena. His research emphasizes the development and use of mathematical models of the atmosphere to study the chemical and physical processes that determine atmospheric structure, aimed primarily towards improving our understanding of the impacts that man-made and natural trace gases may be having on the Earth’s climate and on tropospheric and stratospheric chemistry. He has been a lead author on a number of national and international assessments related to these issues. Dr. Wuebbles was elected a member of the International Ozone Commission in 2000, and in 2005 received the Stratospheric Ozone Protection Award from the U.S. Environmental Protection Agency. He is a Fellow of the American Association for the Advancement of Science and a Faculty Fellow in the National Center for Supercomputing Applications. He, along with many others, shares in the 2007 Nobel Peace Prize for his work with the Intergovernmental Panel on Climate Change.

Dr. Wuebbles also has extensive experience in the study of the effects of aviation on the environment. His expertise and research in the effects of aviation go back to the early 1970s when he was a leader in modeling the potential effects on stratospheric of the then proposed supersonic transport aircraft. Along with publishing many papers and reports on the effects of aviation, he has also been a lead author on several assessments of the effects of current and projected subsonic and supersonic aircraft on the global environment, including lead author on several different chapters of the IPCC special assessment of environmental impacts of aviation in 1999. In 2006, he chaired a major international workshop on the effects of aviation on climate for the FAA and NASA. A journal paper on the findings of the workshop was published in EOS in 2007. He also co-led the climate panel for a major meeting for ICAO on environmental impacts of aviation in October 2007.  He is a member of the FAA’s Energy and Environment Subcommittee of their Research Engineering and Development Advisory Committee.