Supplemental readings from the Reader

Holling, C. S. 2001. Understanding the complexity of economic, ecological, and social systems. Ecosystems 4(5):390-405.

1.4.2.3 HUMAN-ENVIRONMENT SYSTEMS: Realistically sketched interactions - Major dynamical patterns At even more abstract levels, there are efforts to create theory. Thus realism is provided by the attempt to integrate the essence of ecological, economic, and social theory to explain the functioning of socio-ecological systems across spatial and temporal scales. The Reading author borrows from Einstein, stating that efforts to create theory should be “as simple as possible, but no simpler.” This resilience project is currently one of the most frequently employed theoretical lens through which ecological scientists attempt to understand complex human-environment systems.

Lenton, T. M., H. Held, E. Kriegler, J. W. Hall, W. Lucht, S. Rahmstorf, and H. J. Schellnhuber. 2008. Tipping elements in the Earth’s climate system. Proceedings of the National Academy of Sciences 105(6):1786-1793.

2.3.2.2 ANALYSIS: CAUSES, CONSEQUENCE, PROCESSES: Interaction, Impacts, Response - Limits, boundaries, thresholds, and tipping points In nature, rapid phase transitions are common, as in the tiny increment of cooling that turns water into ice. But in human-environment systems, rapid phase transitions are feared, especially if they are poorly understood. So a search for limits (see also 1.4.1.2), dangerous thresholds, and tipping points consume a significant set of scientific attention. A search for “safety” limits for the earth’s life-support and ecological systems are long standing and widespread. Much of it has taken the form identifying “carrying capacity” that limits the use of the earth (see also 1.4.1.2), or “critical loads” that overburdens air or water systems or minimal doses that cause harm from radiation or chemical pollutants. And akin to the phase transition is the concern with tipping points beyond which systems spiral into irreversible change. The Reading illustrates this search for limits, thresholds, and tipping points in the global climate system. Nine tipping elements are identified as extensive components of the earth system, subcontinental in size, affected by human-induced climate change, with potential that a small change across a threshold can trigger a substantial qualitative change. These changes are in ice sheets, ocean circulation, and vegetation.

Cumming, G. S., and J. Collier. 2005. Change and identity in complex systems. Ecology and Society 10(1): 29.

2.4.4.3 INTEGRATIVE METHODS AND MODELS: Models - Complex and cross-scale Complex human-environment systems have many interacting components, some of which behave in non-linear and/or adaptive ways. Thus changes in the system are not simply predictable from the original state of their components. These emergent properties may increase or reduce vulnerabilities across temporal and spatial scales. The Reading which features ecosystem examples focuses on how to define systems and what constitutes processes of change. Five metamodels of complex ecosystem change are offered beginning with Holling’s adaptive cycle (1.4.2.3) and possible variants of randomness, replacement, limitation, and succession.