FIGURE 2.2 Addressing any given societal challenge requires scientific progress in many Earth system areas, as shown in these examples. Colored squares represent the scientific themes that contribute substantially to each of the selected benefit areas.

provide critical new observations and data for addressing emerging societal issues and for enabling major advances in scientific understanding.

The recommended missions address what are considered to be the highest-priority observational needs. To avoid the technical and cost problems associated with overly ambitious missions, the plan limits the instrument set on any mission to one that can deliver clear synergies between observations. In time, it may prove necessary to consider alternative institutional arrangements for executing these inherently multidiscipline, multiagency missions. In particular, as the plans of other space-faring nations and organizations crystallize, their contributions to meeting observational needs will have to be carefully evaluated. Articulated in the next section are the key elements of the current Earth-observing system that are essential components of the observation system for the next decade.