 |
Stratospheric Processes And their Role in Climate
|
||||||||
| Home | Initiatives | Organisation | Publications | Meetings | Acronyms and Abbreviations | Useful Links |
|
Stratospheric Processes And their Role in Climate
|
||||||||
| Home | Initiatives | Organisation | Publications | Meetings | Acronyms and Abbreviations | Useful Links |
The sponsors for this symposium were the Association of European Research Establishment in Aeronautics, EC, IPCC, ICAO, NASA, NOAA, UNEP, and WMO. The objective was to bring scientific, technology and policy leaders together to review the status of relevant atmospheric research, for discussion of potential mitigation measures, and to consider what policy-relevant information may be available to decision makers in the next few years. Such a meeting had never been held and it was believed that the time had come for the scientific community to inform the various policy making bodies of the world of the status of the science with respect to the possible effects of aviation on the atmosphere. It was also felt that it is important for scientists and technologists to hear about the workings and concerns of decision makers. The meeting was hosted by H. Wesoky, the Manager of the Atmospheric Effects of Aviation Project within NASA's Advanced Subsonic Technology and High-Speed Research Programs. The technology and scientific program of the symposium was coordinated by D. Lister of DRA, UK and A. R. Ravishankara of NOAA, USA, with guidance from the organising committee, which comprised representatives of the sponsoring organisations. A total of 150 attendees participated in the meeting. The Symposium was organised into daily tutorials, each followed by reports on special topics of major concern.
The discussions were centred around the following themes:
Prior to the meeting, the speakers were presented with a position paper written by Dr. D. L. Albritton of NOAA, which brought out the likely question that will be asked of the scientists by the policy making community.
One of the important aspects of the meeting was that all the science was presented in a format that was user-friendly to the decision makers. Attempts were made to paint broad pictures of the state of science and hierarchical order of what is known and what is not known. Participants appreciated the opportunity for the different, often non-interacting, communities to interact, and greatly assisted each other in better understanding of the complexities in the relevant science, technology and policy issues.
The symposium was started by welcoming remarks of H. Wesoky. The Symposium's objectives and agenda were discussed by D. Lister and A.R. Ravishankara. J. Crayston talked about the aviation's regulatory standard and Policy Process and D. Albritton discussed the policy/science interactions and their relation to the aviation issue. This was followed by a talk by M. Mann on Economic assessment requirements and a talk by M. Oppenheimer on a public interest perspective on aviation and its impact.
The symposium then moved to the specific science and technology topics listed above. Each session allowed ample time for discussions, which were often lively. Each session had a provocateur to bring out the specific points that are of interest to the decision makers. After the scientific/technological talks, the chairperson and rapporteur provided a non-technical summary of the material. The following people acted as session chairs, rapporteurs, and provocateurs: R. Cottington, A. Fiorentino, J. Levy, U. Wickrama, Ch. Hume, D. Wuebbles, A. Thompson, H. Schlager, S. Sundararaman, M. McFarland, D. Peterson, T. Knobloch, I. Isaksen, R. Sausen, J. Westerberg, H. Grassl, E. Condon, M. Wright, M. Oppenheimer, K. Ryan, G. Angeletti, A. Kaehn, Ri. Niedzwiecki, R. Dunker, and E. Herms.
The session on Aircraft, Engines and Emissions included talks by D. Bahr (Tutorial on Aircraft engines and emissions), J. Elwood (Current Certification Requirements), and D. Lister (Future certification). The session on Current and Forecast Inventories included talks by M. Ralph (Overview), R. Gardner and A. Schmitt (ANCAT Review), and S. Baughcum (NASA review). The session on Tropospheric ozone included talks by G. Brasseur (Tutorial), F. Arnold (Aircraft contribution to tropospheric NOx), J. Logan (How well can we calculate tropospheric ozone and aircraft contributions to this abundance?). The session on Stratospheric ozone included talks by R. Jones (Tutorial), D. Fahey (Where we are in understanding effects of supersonic aircraft?), R. Rood (Special role of strat/trop exchange to aircraft issues), and R. Stolarski (Stratosphere in the year 2050: Can we predict it?). The session on Greenhouse gases and Climate included talks by R. Cess (Tutorial), J. Lelieveld (Influence of chemistry on greenhouse gases), M. Prather (Relationship of radiative forcing to climate), and M. Geller (Climate consequences of ozone changes in the stratosphere). The session on Aerosols, Chemistry and Climate included talks by J. Penner (Tutorial), B. Toon (Cirrus clouds - their connection to climate and aircraft), and B. Kaercher (How do aerosols/clouds change composition and radiation?).
These sessions were followed by a synthesis of what had been discussed and what findings are most important to the aircraft issue. U. Schumann carried out this difficult task.
Following these science talks, emissions from aircraft were discussed by J. Koshoffer (NOx control), D. Snape (Fuel efficiency: CO2/H20 control), and Ch. Kolb (Aerosols and particulates). Air route management and associated topics were discussed by V. Galotti (Air traffic management), M. Ralph (Operational impacts), and J. Crayston (Fiscal measures).
Following these technology and science talks and discussions, a panel of decision makers (H. Aylesworth, J. Erickson, J. Peeters, B. O. Nas, and T. Rowland) reported on what they had heard during these sessions.
The meeting was brought to a close by a panel discussion chaired by D. Albritton (H. Wesoky, D. Lister, M. McFarland, P. Gray, and J. Crayston.) concerning the strategy for assessing the role of aircraft on the Earth's atmosphere.
There were many findings of importance from the symposium. The most important findings were: Aviation is a significant source of the CO2 and its fractional contribution to transportation related greenhouse gas emissions was likely to increase. Aerosols or particulates, which may contribute to global climate change, may be influenced by aviation. The earlier concern about the NOx emission still remains, though its importance relative to the other two influences appears to be less.
Based on many discussions, it was concluded that not enough was known to make definitive predictions of the effects of aviation on the atmosphere, but enough was known to start an assessment process. Based on this finding, the stage was set and a timeline established for focused international assessments of aviation's environmental impact which could serve as a basis for future aircraft emission standards.
A report of the symposium proceedings will be prepared by the organisers and published before the end of 1996.
A. R. Ravishankara