Elevated CO(2) studies: past, present and future.

Increasing concentrations of atmospheric CO(2) are predicted to impact both current and future ecosystems. Elevated CO(2) is also predicted to affect biological processes at many levels of organization. In this overview, we summarize the responses of plants to elevated CO(2) including primary physiological and molecular responses, growth and reproductive responses, effects on plant-plant competition and interactions with other organisms, evolutionary responses, and effects at the ecosystem level. The objectives of this paper are to: (a) overview studies in this issue that were presented at a 1997 meeting entitled "Critical Assessment of the Response of Forest Ecosystems to Elevated Atmospheric Carbon Dioxide," which was sponsored by the Global Change and Terrestrial Ecosystems (GCTE) group of the International Geosphere Biosphere Program (IGBP), (b) review areas of recent progress in CO(2) research, (c) generalize patterns arising from past research, and (d) list critical areas of research for the future.