to their environments. Macroscopic behaviors emerge from these local interactions and
are not imposed or predetermined. Agents (at least some agents) have the capacity to
process information and modify (adapt) their behavioral strategies. Finally, CAS
dynamics are often unpredictable (even if the system is deterministic), and uncertainty is
pervasive” (Levin and Clark 2010, p. 19). Likewise, human-environment systems are
“complex adaptive systems, composed of individual agents that have their own priorities,
and who value the macroscopic features of their societies differently” (Levin and Clark
2010, p. 22), but they are also distinguished from other complex adaptive in several
ways—we will expand upon these differences in subsequent paragraphs.
The mathematical sciences have made essential contributions to many fields of
science, once those fields have been put on a firm quantitative foundation. In the
coming years, it will be natural to pose the question: “what role will the mathematical
sciences play in developing our understanding of human-environment systems as
complex adaptive systems?” There are many reasons to think the role will be very
significant, with the primary difference from previous contributions of mathematics to
other fields stemming from the trans-disciplinary nature of sustainability science. In the
remainder of this white paper we will attempt to outline the potential roles of
mathematical sciences in developing the study of human-environment systems as
complex adaptive systems.
The 2010 report “Toward a Science of Sustainability” outlined three major
themes in the development of HES as CAS: (A) Characterizing and understanding
complex HESs, (B) Local adaptive response and their global consequences, and (C)
Characterizing tradeoffs in HESs. Each of these themes is important, however our
group discussion focused primarily on (A) and secondarily on (B), with little emphasis on
(C). In the following paragraphs we outline more detailed research themes that
correspondingly fall primarily under (A) and (B) of the 2010 report. After describing
some of the research themes that arise in the study of HESs and complex adaptive
systems (section 2), we give further examples of such systems (section 3), followed by
general and specific recommendations (section 4).
- Research Themes
The defining property of Human-Environment Systems (HESs) is the two-way
interaction between humans and the natural environment. In contrast, the social
sciences may be concerned with the social dynamics of interactions between humans
and neglect what is occurring in the natural environment. Similarly, traditional natural
sciences research on environmental systems regards dynamic interactions only within
an environmental system, and the human impact is either absent, or static. In HESs, it is
the dynamical presence of humans in the context of the natural environment that makes
the investigation of HESs particularly challenging. These challenges arise from the range
of scales, both temporal and spatial, that emerge from these interactions.
“Human and environmental systems impact across variety of scales (...that) are
generally mismatched. This mismatch means, for example, that given a spatial scale,
social processes (be they economic, or governmental) are likely to be too sluggish to
deal easily with the rapid changes normally associated with atmosphere, but too rapid
and impatient to recognize and manage many slow but important ecological changes
(e.g. soil depletion)” (Levin and Clark 2010, p.60).