include identifying the criteria for optimizing assimilation techniques for different purposes, estimating uncertainties, and meeting user demands for higher spatial resolution.

The NRC report Informing Decisions in a Changing Climate (NRC, 2009g) recommends that the federal government “expand and maintain national observation systems to provide information needed for climate decision support. These systems should link existing data on physical, ecological, social, economic, and health variables to each other and develop new data and key indicators as needed” for estimating climate change vulnerabilities and informing responses intended to limit and adapt to climate change. It also notes the need for geocoding existing social and environmental databases; developing methods for aggregating, disaggregating, and integrating such data sets with each other and with climate and other Earth system data; creating new databases to fill critical gaps; supporting modeling and process studies to improve methods for making the data useful; and engaging decision makers in the identification of critical data needs. That study’s recommendations set appropriate strategic directions for an integrated data system. Ultimately, the collection and archiving of data for such a system would need to be evaluated on the basis of potential and actual use in research and decision making.

The recommendations in Chapter 5 provide advice on some steps that can be taken to address these challenges.

Nearly every scientific challenge associated with understanding and responding to climate change requires an assessment of the interactions among different components of the coupled human-environment system. A wide range of models, tools, and approaches, from quantitative numerical models and analytic techniques to frameworks and processes that engage interdisciplinary research teams and stakeholders, are needed to simulate and assess these interactions. While decisions are ultimately the outcome of individual, group, and political decision-making processes, scientific tools and approaches can aid decision making by systematically incorporating complex information, projecting the consequences of different choices, accounting for uncertainties, and facilitating disciplined evaluation of trade-offs as the nation turns its attention to responding to climate change. Table 4.7 lists some of the specific research needs identified in Part II of the report that are related to the development of models, tools, and approaches for improving projections, analyses, and assessments of climate change.