1. 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

2. 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

3. 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?)

4. 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?

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

6. 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?

7. 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

8. 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

9. 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

10. 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?

11. 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

12. 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

13. 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

14. 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.

15. (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. 

16. 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…”

17. Tipping points and welfare (a) marginal analysisU 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)

18. 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.