Many readers of this report will find it insufficient. We have admittedly centered our attention on a small subset of the issues and ecosystems that might feel the effects of a rapidly changing climate. Our goal has been to identify those issues and places most important to a society that rightfully expects good guidance from its scientific community. The logical consequence of global climate change is a reallocation of water and the resources it creates. We cannot change that. We can, however, offer specific advice about ways to anticipate and respond to some of the ancillary problems that may develop. Using the power of ecosystem experimentation as the most appropriate tool, we emphasize research on the following prospects:

1. As regional warming occurs, biological communities will disassemble through differential deletions and invasions. New communities will emerge. New management practices will be necessary. Whole-system thermal enhancements can serve to anticipate those responses.

2. Regional warming will profoundly affect wetland systems. In addition to the obvious physical and biological concerns, the prospect of a major change in flux of greenhouse gases must be expected and determined. The possible feedback to atmospheric systems requires large-scale evaluation.

3. Changes in regional hydrology and mean sea level create an important and ironic prospect: sites containing the buried wastes from our past may be disturbed and their toxic contents mobilized to the extent that we must be concerned about major effects in the future. A system of experimental ecosystems in the coastal environment can help guide responses to that prospect.

As more effective forecasts of global climate change emerge, the relative importance of these issues will change. Regardless of that, we encourage the development of perspective and institutional commitments required to increase the use of ecosystem experimentation as a research tool.