erodability of soils). On regional and global scales, assessment of impacts will require application of advanced technologies in sensing, systems modeling, and information technology (e.g., satellite-based remote sensing, three-dimensional relational data models). Corresponding advances will be required in the understanding of our social (human) systems and their interactions with natural systems. Furthermore, the uncertainties associated with predicting the regional and global impacts of technologies mandate application of adaptive management techniques (i.e., the observational method) in ESE (see Sidebar 4.4). No other discipline is better positioned than geoengineering to undertake many of the engineering challenges of ESE.
We agree with the importance attached to ESE by the NAE and see the emergence of a new metadiscipline of GES as a subset of ESE. We define GES broadly as the integration of all disciplines related to geoengineering for earth systems, at all scales. Our definition therefore includes (1) microscale phenomena that affect bonding, conduction phenomena, and other particle-level interactions; (2) the midscale behavior of particle assemblages, including shear strength, dispersion of contaminants in Earth materials, erodability, and hydraulic conductivity; (3) macroscale behavior, such as slope stability and surface water infiltration; (4) megascale phenomena such as regional sediment transport and groundwater aquifer recharge; and (5) engineering required for mitigation on global climate change.
GES encompasses all of the seven areas where geotechnology contribute to national needs identified in Chapter 2: (1) Waste management (and environmental protection); (2) infrastructure development and rehabilitation ; (3) construction efficiency and innovation; (4) national security; (5) resource discovery and recovery; (6) mitigation of natural hazards; and (7) frontier development and exploration. However, by definition and by necessity the GES perspective on these issues is a global systems perspective.