We are increasingly aware that we are living in a tightly integrated Earth system where anthropogenic activities have a noticeable, and even dominant, effect on the planet. Accumulations of local activities have an effect on the large-scale behavior, and there are no isolated activities. The recognition of the importance of these phenomena has led the Earth science community to identify a new discipline: Earth Systems Science (ESS). ESS links the biosphere (all life on Earth), geosphere (the rocks, soil, water, and atmosphere of Earth), and anthrosphere (political, economic, and social systems) in order to understand and predict the behavior of Earth systems. From the engineering perspective, each design decision may have systems consequences in other parts of the world, and sometimes these consequences are large, sudden, and unanticipated. Geoengineers need to understand and appreciate the natural interrelationships that tie Earth systems together, and the feedback that is inherent in these systems. As Sarewitz (NAE, 2002) points out, it is a mistake to consider these problems only as scientific issues in which action depends only on gaining fundamental knowledge. Rather, as Sarewitz continues, owing to their global importance we would do better to consider these issues as engineering challenges.
The increasing importance of sustainable development, including the growing recognition that the quality of our engineering directly affects the quality of society and the lives of future generations—combined with the recognition that many engineering decisions cannot (or at least should not) be made independent of the context of the surrounding social systems—has lead to the emergence of ESE as a corollary to ESS. ESE was described by William A. Wulf, president of the National Academy of Engineering (NAE, 2002), as “an emerging multidisciplinary area based upon a holistic view of the interactions between natural and human systems. ESE addresses global, complex, multiscale, multicycle phenomenon, such as climate change, as well as problems of global importance such as urban design.” ESE is the tool, or collection of tools, for helping to achieve sustainable development on regional and global