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Moving Forward with Imperfect Information 439Figure 19.1 Working with uncertainty. Continuum of uncertainties, knowledge gaps and challengesrelated to projecting future climate changes and their impacts, and assessing vulnerabilities to futurechanges. See Tables 19.1 and 19.2 for syntheses of knowledge and uncertainties identified by authorsof this assessment report. Adapted from Pidgeon and Fischhoff (2011).2011). Although numerous emissions paths are represented in the GHG scenarios, theydo not precisely translate into changes in radiative forcing (i.e., changes in the balance ofradiated energy), which can warm or cool the climate system.Observational data is a key research need that feeds into these uncertainties. Fewerobservations make it difficult for scientists to tease out the information they need to accuratelyrepresent climate dynamics. In the Southwest, there are minimal climatic andmeteorological observations for much of the region, especially at high elevations and ontribal lands—thus impeding our understanding of regional climate processes.Model uncertainty can also be attributed to factors affecting climate that have yetto be identified (Risbey and O’Kane 2011). Consider the role of aerosols in moderatingclimate. Prior to 2003, the role of these particulates in the atmosphere and in regulatingclimate was unknown, and so they were not represented in GCMs. They were an