rely on qualitative metrics arrived at through a consensus of experts. For example, qualitative metrics (such as “virtually certain,” “likely,” etc.) are used in the IPCC assessment. For these metrics to be useful, all participants, including policy makers, must share and accept the meanings intended by the qualitative metrics. Other formal approaches to developing expert consensus, such as the “Delphi method” and techniques for drawing conclusions based on a range of expert judgment, have been developed (De Groot 1970; Oalkey 1970; Watson and Buede 1987; Morgan et al. 1984).
Scenario analysis can be a useful tool for developing insights on the importance of key uncertainties and where additional research may have the greatest payoff. Where there are legitimate differences in opinion over the true state of the world, the scenario analysis approach can help clarify the importance of alternative assumptions and resolve seemingly intractable conflicts by illustrating a range of potential outcomes. However, scenario development is information intensive and requires data that are internally consistent. Such information may or may not be readily available. Further, scenarios are frequently confused with predictions of future conditions, so communication of appropriate ways to interpret them is essential.
If an assessment’s scientific findings are effectively communicated, understood, and accepted by the target audience, there is a greater chance that optimal policies and decisions will be undertaken to address the environmental challenges analyzed in the assessment. Ideally, the communication strategy involves a multifaceted approach: getting to know the target audience, recognizing its information needs, and actively engaging its members in the process (Moser and Luganda 2006). In designing a communication strategy, the assessment team should try to analyze and respond to the interests, motivations, receptivity, knowledge base, barriers, and resistance of different target audiences (Moser and Luganda 2006; Moser and Dilling 2007). The basic objective is to stimulate individuals to think about problems, risks, and solutions, and thereby to influence policies, decisions, and behavior.
The communication process should be active during the entire assessment, and not solely be designed around the report dissemination. Effective assessments have a comprehensive, multifaceted communication strategy right from the start, encompassing an analysis of the target audiences, alternate modes of reaching and engaging them, desired responses (e.g., policy decisions, legislation, technological innovation, standards, international