GEIA's work cuts across and contributes to all of IGAC's other activities. Its inventories provide a scientific foundation for policy initiatives designed to address urgent environmental issues such as global warming, stratospheric ozone depletion, acid precipitation and biological damage [Graedel et al., 1993]. As these issues become more pressing, GEIA has entered a new phase of growth and responsiveness to an expanding user community.

GEIA includes several hundred scientists from around the world, many of whom are involved in other IGAC Activities. GEIA's work is guided by Co-Conveners Derek Cunnold of the Georgia Institute of Technology (USA) and Jos Olivier of RIVM, the Netherlands National Institute of Public Health and the Environment. Paulette Middleton, RAND (USA) directs the GEIA Center in Boulder, Colorado, the hub of data access and communication. Cunnold, Olivier and Middleton work closely with an international coordinating committee, including Carmen Benkovitz, Brookhaven National Laboratory (USA), Gregg Marland, Oak Ridge National Laboratory (USA), Ann McMillan, Atmospheric Environment Service (Canada), Jozef Pacyna, Norwegian Institute for Air Research and Trevor Scholtz, ORTECH Corporation (Canada).

Figure 1. A graphic depiction of global distribution of carbon dioxide, one of the highly policy-relevant compounds inventoried by GEIA.

Guiding Principles

GEIA was created in 1990 to encourage the development of global emissions inventories of gases and aerosols emitted into the atmosphere from natural and anthropogenic sources. The long-term goal is to provide inventories of all trace species relevant to global atmospheric chemistry. As with all IGAC Activities, GEIA tries to include all interested parties on a volunteer basis. Emissions inventory experts from individual countries, supported by local organizations, conduct their own research while maintaining contact through GEIA's communications network and participation in periodic meetings. The GEIA forum allows participants to discuss their work and draw upon the combined expertise of their fellow members. This coordination ensures that results of their work are compatible and can be combined with a minimum of effort into a uniformly formatted data set.

GEIA's operations are organized around four principles:

1. GEIA's goal is to produce emissions inventories for all species of interest on a 1° x 1° global grid and a country-by-country basis.

2. GEIA inventories are accompanied by an assessment of their degree of uncertainty, as well as a comparison with results of top-down global or regional budget studies, if available.

3. GEIA seeks to provide comprehensive information for each database, including:

• sectoral information
• natural sources, if appropriate
• temporal variation, at least by season/month
• historical emissions, as a separate product
• periodic updates, e.g., emission estimates for 1985 and 1995

4. GEIA project teams are international and intercontinental.

Achievements and Plans

GEIA's achievements over the past decade include:

• a growing user community
• more than two dozen projects and many completed and available inventories
• the GEIA website
• ten international planning workshops
• links to related efforts

These achievements contribute to building a strong and solid foundation for the future of GEIA. The dedicated core teams, successful projects, establishment of a website, long-term planning enhanced by frequent international workshops, increasing attention to the user community, and forward-looking approaches to coordination and collaboration are all important elements of GEIA's future.

Conveners and Participants

The first convener of GEIA was Thomas Graedel, now at Yale University, with Gregg Marland of Oak Ridge National Laboratory succeeding him in 1996, followed in May 1998 by co-conveners Derek Cunnold of the Georgia Institute of Technology (USA), and Jos Olivier of the Netherlands National Institute of Public Health and the Environment (RIVM). Including the Coordinating Committee, groups responsible for development of the inventories and active users, there are now over 200 members in the GEIA e-mail network. Many project leaders and Coordinating Committee members have been part of GEIA since its inception in 1990.

Inventory Development Activities

The current status of GEIA inventories is listed below. In the following list, (A) indicates emissions from anthropogenic sources and (N) emissions from natural sources.

Compounds (available): Ammonia (A&N), Black Carbon (A), Carbon Dioxide (A), Carbon Monoxide (A), Chlorofluorocarbons (A), Lead (A), Mercury (A), Methane (N), Sulfur and Nitrogen Oxides (A), Nitrous Oxide (A&N), Reactive Chlorine Emissions (A&N),Volatile Organic Compounds (A&N).

Compounds (in progress): Methane (A) (preliminary 1990 GEIA inventory available at EDGAR website), Organochlorines (A), Radionuclides (N), Dimethylsulfide (Reduced Sulfur) (N), Primary Particles (A,N).

Source-Specific Emissions (available): Aircraft Emissions (A), Lightning (N), Nitrogen Oxides in Soils (A), Sulfur from Volcanoes (N).

Source-Specific Emissions (in progress): Biomass Burning (A & N), International shipping.

Other Data (available): Population, Cropland.

The April 2000 IGAC integration and synthesis project meeting in Aspen, Colorado generated additional support for several key GEIA data development activities, many of which are already in the GEIA Five-Year Plan:

• Provide inventories for roughly every 10 years over the past 30-50 years
• Provide seasonal cycles in the emissions
• Provide formulae for the dependence of natural emissions on soil moisture and temperature
• Further evaluate NO_X emissions from soils
• Provide biomass burning emissions as a function of burning temperature and land use practices
• Combine the GEIA and EDGAR databases
• Provide organohalide emission estimates
• Distinguish between emissions into the canopy and those that reach the global atmosphere

GEIA will be pursuing these and related activities in the coming months. In particular, emphasis is being given to bringing the CO, CH₄, biomass burning and aircraft and ship emissions data online. GEIA is also developing enhanced question/answer feedback procedures, expanded formats, and flexible downloading protocols.

The GEIA Center

The hub of the global network of institutions and agencies developing these emissions inventories is the GEIA Data Management and Communication Center. The Center's activities are supported by the U.S. National Science Foundation (NSF) and National Aeronautics and Space Administration (NASA) and directed by Paulette Middleton of RAND Environment. The Center's role is to manage the website, to coordinate the distribution of emission inventory data, and to manage GEIA outreach activities.

As part of the expanded outreach strategy to enhance the exchange of information on GEIA and to encourage participation in GEIA, the GEIA Center recently developed the GEIA Newsletter. Each newsletter will have highlights from projects and workshops as well as other timely news related to global emissions inventories. The first newsletter can be found at http://weather.engin.umich.edu/geia/ and can be downloaded in PDF format. This allows the newsletter to be printed in hard-copy form or to be passed on to other interested readers.

In addition to this newsletter, the GEIA Center is expanding its e-mail network, establishing more two-way links to related websites, and developing information materials such as a new brochure. The website survey of users is being upgraded and follow-up discussions with users are being initiated. The survey will be similar to one developed in 1998 to help in the development of GEIA's first 5-year plan. The survey requested information on users and their use of the GEIA data, their evaluation of the databases, and more detailed evaluation of specific data sets and needs. Results so far have been extremely valuable in developing effective ways to improve the quality and usefulness of GEIA data.

Currently the GEIA Center tracks the number of visitors to the GEIA website, the number and type of downloads, and users' comments regarding their use of the data and general suggestions for GEIA. The results of this tracking are located on the GEIA site. For example, there were 540 downloads of data in 1998 and 704 downloads in 1999. The nitrogen oxides inventory was most popular in 1998, while natural VOC inventory was the most popular download in 1999.

As previously indicated, the major goal of GEIA is to provide peer-reviewed, documented emission inventories. However a number of emission inventories have been developed for specific needs, e.g., by modelers, independently of GEIA activities. It is the GEIA intent to be a focal point for information on emissions. Therefore, in cases where there is no GEIA inventory for a particular species, the GEIA website has added links to other data sources, e.g., to the EDGAR database.

Workshops

Workshops are essential to GEIA's productivity and growth. International workshops on global emissions inventories have been held approximately once each year since GEIA was organized. The workshops have usually been organized in conjunction with major, related international meetings. All scientists involved with either emission inventory preparation or using emission inventories are encouraged to attend these meetings.

Previous Workshops

1. September 1990, in Chamrousse, France, in association with the 7th CACGP Symposium on Global Atmospheric Chemistry.
2. December, 1991 in Baltimore, Maryland, USA, in conjunction with CHEMRAWN (Chemical Research Applied to World Needs).
3. June, 1992 near Oslo, Norway, sponsored by the Norwegian Institute for Air Research.
4. Early 1993 at Amersfoort, The Netherlands, under the auspices of the National Institute of Public Health and Environmental Protection.
5. Late 1993, at NCAR, Boulder, Colorado, USA with modelers in conjunction with a symposium on "Challenges in Atmospheric Chemistry and Global Change: Yesterday, Today and Tomorrow," held by NCAR to honor Paul Crutzen on his 60th birthday.
6. September, 1994, in Fuji-Yoshida, Japan in conjunction with the Eighth CACGP Symposium and the Second IGAC Scientific Conference.
7. July, 1995, in Gothenburg, Sweden in conjunction with the conference "Acid Reign 95".
8. May, 1996 in Toronto, Canada.
9. November, 1997 in Bilthoven, The Netherlands, hosted by the Netherlands Governmental Agency on the Environment and followed by the IPCC Expert Meeting on Methods for the Assessment of Inventory Data Quality on 5-7 November 1997.
10. August, 1998 at the University of Washington, Seattle, Washington, USA, in conjunction with the Joint CACGP/IGAC International Symposium on Global Atmospheric Chemistry.
11. September, 1999 in Bologna, Italy, in conjunction with the Sixth IGAC Scientific Conference.

Invitation and GEIA Contacts

Everyone is invited to become involved in GEIA and to contribute to emission inventory preparation. Feedback on GEIA databases, their access and suggested improvements are always welcomed. Contributions to the evaluation of existing emission inventories and their uncertainties are especially valuable.

Details on GEIA, the five-year plan, results of a GEIA-wide survey that provided input for the planning process, and the GEIA projects and data themselves, can be found at http://www.geiacenter.org, along with information on future GEIA meetings.

Reference

Graedel, T.F., T.S. Bates, A.F. Bouman, D. Cunnold, J. Dignon, I. Fung, D.J. Jacob, B.K. Lamb, J.A. Logan, G. Marland, P. Middleton, J.M. Pacyna, M. Placet, and C. Veldt, A compilation of inventories of emissions to the atmosphere, Global Biogeochem. Cycles, 7, 1-26, 1993.