outcomes. There are some predetermined elements in 30-50 year time frames, but not on longer scales. Even demography can change fundamentally in a decade. Even things considered physically impossible can become possible in a decade. The task in modeling, Schwartz emphasized, is to have different models that embody different theories of change—not different runs of the same model, which is sensitivity analysis. Rigorous models are needed that lead to different conclusions—different interpretations of history, leading to different projections.

Building models thus requires both rigor and imagination, even for a 50-year time frame. People are remarkably capable of failing to see signals of impending change. Good scenario thinking allows one to see the signals of fundamental change when they arrive. Schwartz concluded by warning that people need to take the idea of story telling seriously, because stories give meaning to facts.


Thomas Wilbanks

Thomas Wilbanks spoke about lessons from the U.S. National Assessment (USNA). The first USNA occurred in 1997-2000, with $14 million of federal funding.2 It included 16 regional and 5 sectoral assessments and a top-down overall document. Wilbanks noted that a survey-based effort led by Granger Morgan to gather lessons from the first USNA found that many participants thought the future would be like the present except for the climate, and others thought that nothing useful could be said about the socioeconomic future because it is so complicated (Morgan et al., 2005). Morgan’s group produced a guidance document, asking each group to pick one or two factors that they thought would be influential and to consider different values of these; however, this guidance was little used. The survey study concluded that the process got considerable stakeholder involvement and that those who were heavily involved were more favorable about the process. It concluded that the USNA worked best with the ecosystem topic, which was done very well. People considering the USNA concluded that it was very imperfect, but that a better process would probably have reached the same conclusions.

The initial vision of the first USNA was bottom-up; a top-down part


The slide presentation, which was prepared primarily by Granger Morgan, is available at http://www7.nationalacademies.org/hdgc/US_National_Assessment_Presentation_by_Granger_Morgan.pdf [November 2010].


Reports of the U.S. National Assessment completed in 2000 can be found at http://www.usgcrp.gov/usgcrp/nacc/ [November 2010].

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