Emergent Properties of Coupled Systems Presenter: B. Turner; Moderator: J. Heffernan; Discussants: Cambridge Group

Definitions & Clarifications Emergence Is Not: “whole = more than sum of parts” (unexplainable) Is: patterns arising from many simple interaction of complex systems (knowable but surprise) CHES emergence ideally involves coupling, both subsystem some examples = focus on one subsystem In almost all cases of emergence in CHES ≠ dealing with “strong” emergence (as in philosophical questions of epistemology or ontology) but with “weak” emergence (complexity of interactions = nonlinear responses)

Types of CHES Emergence Aggregate attributes (system-wide attributes?) of the CHES vulnerability or resilience of CHES Flip or switch of CHES (classical emergence) tipping points/elements = trajectories of change can be in one subsystem complex system & earth system science

Vulnerability & Resilience Complimentary but different framings of CHES characteristics V = weakest part of system (historically in human subsystem

Vulnerability & Resilience Complimentary but different framings of CHES characteristics V = weakest part of system (historically in human subsystem) R = defines V as antonym of R

Meanings V = degree to which CHES or some part likely to experience harm due to exposure exposure, sensitivity, coping capacity/resilience R = the amount of disturbance a system can absorb and remain within the same state or domain of attraction Alt.: capacity to self organize or learn and adapt V = largely from social science; R = from ecological science

Applications for CHES T’s Pivots V R CHES, Environmental Services (ES), Tradeoffs (T) [Emergence?] V From social science for human subsystem Minimal attention to ES beyond provisioning kind and to processes of env. subsystem, especially with CHES in mind Calls for T analysis; few attempted Virtually no attention to emergence R From ecological science with framework drawn almost wholly from it Strong attention to ES; core idea Attention to tradeoffs, both economic and physical [metrical] Attention to tipping points/elements [largely from environmental science]

Therefore V = only beginning to address the pivots & then by only a small portion of the practitioners adhering normal science Not clear that emergent properties have been identified for CHES or its subsets (e.g., coping/adaptive capacity) R = grounded in the pivots & all practitioners adhere to normal science Some emergent properties advanced All drawn from biophysical world Not clear they are applicable to both subsystems E.g., key = slow acting variables which tend to be macro-scale in kind

Tipping Points & Elements TP = threshold condition in which a small perturbation qualitatively alters state of system Emanates from climate sciences (focused on changes in biophysical world) TE = significant variation of parameters controlling system  qualitative change which may not register immediately (time interval) Notion that direct human action involved

Lenton, T. M. , et al. 2008. Tipping elements in the Earth’s climate Lenton, T.M., et al. 2008. Tipping elements in the Earth’s climate. Proc. Natl. Acad. Sci. U.S.A. 105, 1785–1793.

Coupled system tipping: possible Maya case Climate change: < wet & > dry seasons < evapotranspiration < precipitation < P capture [> > soils maintenace costs] Hurricanes: ? Landscape walls Soil: > temp < moist > reservoirs > wetland agr < 150 m amsl > invasive bracken fern [> agr costs] Preclassic flush of soil and nutrients [countered by terraces +] Influx Maya clays; increase of seasonal bajo forest >150 m karst deep aquifer

Commonalities? Examples of increased V/decreased R & tipping points in CHES Maya, Angkor Watt, Aral Sea Move to new, qualitatively different state of CHES state The environmental subsystem appears to recover in somewhat modified state Including northern part of Aral Sea Fewer examples of human subsystem recovery and environment does not Exceptions: Leadville, Co.