HR: 13:40h
AN: A23E-01 INVITED     [Abstracts]
TI: Do We Understand the Environmental Impacts of an H2 Economy?
AU: * Prather, M J
EM: mprather@uci.edu
AF: Earth System Science Dept, UC Irvine, 3329 Croul Hall UC Irvine, Irvine, CA 92697-3100 United States
AB: The promise of a clean, hydrogen (H2)-fueled transportation sector has been waved in front of the nation by the current administration, the governor of California, and the technologists. A 2004 NAS report on "The Hydrogen Economy" was prepared by the economists and engineers, remarkably lacking any atmospheric scientists or biogeochemists who understand the natural cycle of H2. It is surprising that all of these groups examining a hydrogen economy are secure in the belief that H2 is a pure fuel, safe and harmless to the environment. A thorough well-to-wheel analysis as envisaged by the NAS report is needed to evaluate the environmental costs/benefits of a hydrogen economy (e.g., the energy source for producing H2, the distribution system), but it needs also to include our knowledge of the biogeochemical cycling of H2 in the atmosphere (0.5 ppm or about 175 Tg) and how it might be perturbed. This brief review of the science examines what controls the atmospheric abundance of H2 and how the chemistry of H2 impacts the climate and global air quality. Recent work on hydrogen isotopes, global modeling of sources and sinks, and the stratospheric and climate connections, enables us to more clearly define the budget and impacts of H2, and to place reasonable bounds on the environmental impacts - provided we understand the possible future emissions of H2 and of related direct and indirect greenhouse gases.
DE: 0315 Biosphere/atmosphere interactions
DE: 0322 Constituent sources and sinks
DE: 0330 Geochemical cycles
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting