may be of profound interest to agribusiness, natural resource managers and industries, water supply managers, and others. Decadal projections will be of interest to these groups and others, such as those making long-term investment decisions (e.g., the oil and gas industry in Alaska, which has long operated on ice roads constructed according to historic permafrost conditions that may now be changing). Moreover, the projected growth of the U.S. population by nearly 100 million people in the next 40 years will cause additional demand on resources that will be affected by climate variability and change. Discussion of user needs in the document, in whatever chapter, should provide some context related to demographic changes (population, geographic density, immigration and risk, etc.) that may further change needs for climate projections, particular on long time scales, and perhaps also for better characterization of uncertainty in the projections.

Until near the end, the chapter proceeds without recognition that (as noted elsewhere in the document), federal science agencies often lack understanding of the needs of users and of how to appropriately integrate them. For example, a recent National Research Council (2006b) review of the Advanced Hydrologic Prediction Service showed that the National Weather Service had only marginally considered a user integration strategy. The Advanced Hydrologic Prediction Service, a suite of tools to enhance the river forecast centers, was virtually unknown by the floodplain management community, a key potential user. Innovation by forecasters may have little to do with making climate information more useful to decision makers, but this possibility is barely addressed or considered in this chapter. The way this chapter is written makes it difficult to determine if the authors are raising concerns related to the ineffective incorporation of users into the process or continuing to write from a model that does not fully recognize the challenges of user engagement.

There are some apparent references to comments made by attendees at a workshop or conference. It would be helpful to know more about the methods used to collect information, including at the workshop or conference. However, such anecdotal information cannot substitute for a discussion of the published research on this topic.

The organization of Chapter 4 needs to be revisited to reduce redundancies and treatment of the same topics in multiple places. In addition, in several instances, the contents of the sections do not correspond closely to the central questions identified in the subheadings. The case studies do not make a clear effort to develop the major themes and observations made in the text or to support the key findings of the chapter.

The language needs careful review for consistency and accuracy, so that climate variability and climate change do not appear to be used interchangeably and so that projections are not confused with forecasts.

This chapter suffers from too much technical jargon that is not clearly related to the context of water resources. For example, does “adaptive management” as used in this chapter mean anything more than simply changing strategies as new information becomes available? If more is meant, the meaning should be made clear.

The term “decision-support system” should be given a clear definition for the water resource management context. The term is critical in Chapter 4 but should be defined early in the report. How the authors see the term as being defined for water resource management would