Sustainability Science Seminar Emergent Properties of CHES Student response: Cambridge Student Presenters: Leah Stokes, Jess Newman, Dominic Maxwell Erin Frey, David Bael, Tara Grillos, Lilli Margol, Suhyun Jung November 1, 2010

Agenda Conceptual Framework: Definitions of emergence, resilience, vulnerability using examples The social science side of resilience /adaptive capacity Predicting tipping points and understanding their effects on well-being valuation

1. Conceptual framework Emergence Chapter does not define emergence Different definitions exist in the literature (e.g. Cunningham, 2001): Informal definition: the “surprise” event or tipping point A property of a system not reducible to the properties of its component parts (vulnerability and resilience?)

1. Conceptual framework Vulnerability Resilience “the degree to which a system, subsystem, or system component is likely to experience harm due to the exposure to a hazard.” Resilience “the ability of an environmental system ‘to absorb change and disturbance and still maintain’ its base structure and function, including reorganization of the system.” Question: How do these terms relate?

1. Conceptual Framework – Example 1 Sahel Drought from 1960s onward Research questions: Regime shift? Human or environmental cause? Foley et. al 2003

1. Conceptual Framework – Example 1 Sahel mechanisms Environment: climatic changes in sea surface temperature, driving precipitation changes Human: land-use change, local deforestation potentially amplifying the cycle Difficult to tease apart human and environment contributions How can we describe this system using the book’s framework? Low resilience? High vulnerability?

1. Conceptual Framework – Example 2 Fisheries economics Human and environment systems operate at different timescales Economic incentives drive towards “bionomic equilibrium” Human system dynamics (e.g. fisherman have mortgages; uncertainty about population; political pressures) means non-optimal harvest rate

1. Conceptual Framework – Example 2 Fisheries biology Selective pressures from fishing can change the underlying genetics of the fish population Can drive species (and industry in CHES) to a tipping point Are these tipping points emergent properties? Loss of resilience? High vulnerability? Law, 2000

Exploring the “human/social side” of CHES Question 2 Exploring the “human/social side” of CHES Social Resilience vs. Human Adaptive Capacity Social Resilience of CHES as Inherently Emergent Mangrove conversion and institutional resilience in Vietnam Reconciling the way we view properties of environment and social systems to describe and measure emergent properties

Social Resilience and Human Adaptive Capacity “Social resilience” and “human adaptive capacity” are often used interchangeably. Are they actually the same? Neutral terms? Time frames? Scale? Whose resilience? Whose adaptive capacity? Bounding?

Social Resilience Social institutions (behavioral norms and structures of governance) are subject to external pressures/shocks from political and economic change. The ability to absorb these changes depends on social capital and the characteristics of the local resource systems. In a CHES, the buffer capacity of the social system to absorb perturbations can’t be separated from the characteristics of the environment system Adger 2000

Example: Mangrove Conversion and Institutional Resilience in Vietnam The buffer capacity of social institutions and norms to absorb perturbations will not approach tipping points as long as the core functions of its resource base are not perturbed beyond a certain range. When the ecologic resilience is overwhelmed, the social resilience collapses. Adger 2000

Social vs. Environment? ? How we think about… Environment Systems Social Systems Coupled Systems Valuation Species/population level Individual level ? Adaptation Evolutionary Quick: choice, decision-making, free will Resilience/Tipping Points Exogenously and analytically determined Endogenous and socially constructed (ethics, knowledge, attitudes to risk, culture) Adger 2009

Q3: Implications for policy Or, now that we know about CHES emergent properties, what do we do differently on Monday morning? At simplest: exercise caution – a point for the precautionary principle.

(1) Early warnings of a tipping-point ↑ Slowness of recovery ↑Increased variance ↑ Autocorrelation Source: Scheffer et al. 2009: Early-warning signals of critical transitions. Nature. 

How plausible is this? Advantages Disadvantages Doesn’t require understanding of underlying mechanisms Only works if there is a gradual approach to a threshold Requires long time series Confounding trend in perturbations – leads to false positives. Also: political plausibility? [Will CC often mean a confounding trend in perturbations? Just becomes a noisier system?] “Please pass expensive regulation. We don’t know exactly why x will happen, but we think the autocorrelation has gone up…”

Tipping points and welfare (a) marginal analysis U 1 Value (e.g. ecosystem services) xtp x (eg forest cover) 2 Uncertainty over tipping point E[U] 3 Expected value x (eg forest cover)

Tipping points and welfare (b) fundamental uncertainty Analysis Implications Structural uncertainty: unknown probability distribution of impacts This makes the expected impacts the “expectations of expectations”: fattens the tails (Student-t distribution) Increasing impact dominates decreasing probability Simulations are misleading (Monte Carlo, IAM) For climate change: potentially greater effects on CBA than the choice of discount rate CBA “arbitrarily inaccurate” Prob. Source: Weitzman (2009) “On modeling and interpreting the economics of catastrophic climate change”. Review of Economics and Statistics. Weitzman (2007) “A Review of The Stern Review on the Economics of Climate Change”. Journal of Economic Literature. Future growth under BAU Source: Weitzman (2009) “On modeling and interpreting the economics of catastrophic climate change”. Review of Economics and Statistics. Weitzman (2007) “A Review of The Stern Review on the Economics of Climate Change”. Journal of Economic Literature.