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Transcript of David B. MacNeill Fisheries Specialist NY Sea Grant Extension SUNY Oswego [email protected] Global...
David B. MacNeillDavid B. MacNeillFisheries SpecialistFisheries Specialist
NY Sea Grant ExtensionNY Sea Grant ExtensionSUNY OswegoSUNY Oswego
Global Climate Global Climate Change Change
and Uncertaintyand Uncertainty
Global Climate Change and Global Climate Change and UncertaintyUncertainty
Polar bears
Al Gore
Apocalypse
Junk Science
Greenhouse gases
Glaciers
Kyoto
Decision-making
DisasterIPCC
Tradeoffs
Human dimensions
Policy implementation
Human behavior
Public perceptions
Mitigation
Heresy
CommunicationAdaptationScenariosSocial Sciences
Climate models
Biodiversity
Chicanery
Conspiracy
This This Presentation:Presentation:
• Broad-brush overviewBroad-brush overview of climate change of climate change uncertainties, communication etc. from uncertainties, communication etc. from literature sources, extension experience literature sources, extension experience with scientific uncertainty.with scientific uncertainty.
• NotNot an indictment of science or an an indictment of science or an admonishment of scientists, policy admonishment of scientists, policy makers, government or the lay makers, government or the lay community!!community!!
Understanding the concepts of risk and Understanding the concepts of risk and uncertainty with a deck of cards??uncertainty with a deck of cards??
The uncertainty: What poker hand will I draw next?
The risk: What is the probability of drawing it? (<1%)
The Dead Man’s Hand: unlucky for Wild Bill Hickok?
But, the card deck changes But, the card deck changes unexpectedly……unexpectedly……
The Risk ?
Death cards
Other cards
Some Climate Change Some Climate Change PerspectivesPerspectives
• A complex, multidisciplinary issue of long-A complex, multidisciplinary issue of long-term global consequence, that demands:term global consequence, that demands: – Best available information Best available information – New assessment, predictive, decision-making New assessment, predictive, decision-making
toolstools– A carefully planned extension/outreach A carefully planned extension/outreach
strategystrategy– Better PR for scienceBetter PR for science
• An opportunity to:An opportunity to:– Inform communities: climate science, risks, Inform communities: climate science, risks,
abatement abatement and and science 101science 101– Assist coastal communities: decision-making Assist coastal communities: decision-making
Global Climate Global Climate ModelModel
• Many different disciplines.Many different disciplines.
• Highly uncertain events; outcomes poorly defined.Highly uncertain events; outcomes poorly defined.
• Interactive anthropogenic and natural events.Interactive anthropogenic and natural events.
• Future outcomes sensitive to small changes in current Future outcomes sensitive to small changes in current conditions.conditions.
• Incomplete understanding of climate system. Incomplete understanding of climate system.
• Imprecise models: feedbacks, interactions, parameter Imprecise models: feedbacks, interactions, parameter values.values.
• Huge jigsaw puzzle having 10s of thousands of pieces.Huge jigsaw puzzle having 10s of thousands of pieces.
• Compilation: decades of intensive, international research.Compilation: decades of intensive, international research.
Climate Change Climate Change ComplexityComplexity::
Uncertainty leads to those nagging Uncertainty leads to those nagging questionsquestions
Is climate change real?, are humans Is climate change real?, are humans responsible?responsible?
• What are the impacts?, What should we do?What are the impacts?, What should we do?
• Why: Why: – is science uncertain?is science uncertain?– do scientists disagree? change their minds?do scientists disagree? change their minds?– don’t scientists always have the answer?don’t scientists always have the answer?– do results contradict?do results contradict?
Uncertainty Uncertainty paradigmsparadigms
•Uncertainty is unwelcome, and needs to be avoided. Science must eliminate uncertainty through more and better research.
•Uncertainty is undesirable, but unavoidable. Science must estimate and quantify uncertainty as well as possible.
•Uncertainty creates opportunities. Science must contribute to more inclusive, understandable discussions.
•Uncertainty is an integral part of decision-making. Science must have more societal influence.
Communicating Science and Communicating Science and UncertaintiesUncertainties
Why even bother ???Why even bother ???
• PR: The process of science.PR: The process of science.
• Restore credibility of science: increased Restore credibility of science: increased transparency.transparency.
• Provide accessible information/knowledge to Provide accessible information/knowledge to decision-makers.decision-makers.
• Decision-making: accurate and collaborative. Decision-making: accurate and collaborative.
• Increase public support/involvement: Increase public support/involvement: decision-making decision-making
• Enhance societal abilities: adaptation & Enhance societal abilities: adaptation & mitigationmitigation
• GCC interactions: science and human ecologyGCC interactions: science and human ecology
Three Arguments for Climate Three Arguments for Climate ChangeChange
• Climate is changing: analyses of many Climate is changing: analyses of many indicatorsindicators
• Human activities have contributed to increases Human activities have contributed to increases in green house gas emissionsin green house gas emissions
• Scientific deliberations and large-scale Scientific deliberations and large-scale computer models suggest potential for climate computer models suggest potential for climate change from anthropogenic influenceschange from anthropogenic influences
• High degree of confidence: weight of evidence High degree of confidence: weight of evidence from expert opinionfrom expert opinion
Is climate Is climate reallyreally changing?changing?
Surface temperature record
Sea Ice
Sea level
Glacial record
Sub-surface
ocean
temperatures
Climate proxies
Convincing evidence
BUT..
Contentious Points
Climate cycles
Remote sensing
calibration
Climate proxy
accuracy
Policies:
people or nature
Model predictive power
Climate sensitivity Earth’s resiliency?
Solar activity
Natural vs. anthropogenic
Muir Glacier Alaska, August 1940. photo by W.O. Field
Seeing is Seeing is Believing?Believing?
Muir Glacier Alaska, August 2004. photo by B.F. Molnia
Uncertainty
Scientist Non-scientist
“You just don’t understand.” “It’s too complicated”. “We know what is best.” “It’s not our job to explain it to you”. “We’re scientists, not interpreters”.
“Science is sloppy - a collection of useless facts”. “You’re arrogant, out-of touch and have impractical ideas”. “You’ve been wrong before.”“Prove it.”
An exaggerated An exaggerated view…..view…..
Some major Some major challengeschallenges
• Continuing uncertainties on climate system sensitivity to Continuing uncertainties on climate system sensitivity to various feedbacks (e.g., clouds, water vapor, snow).various feedbacks (e.g., clouds, water vapor, snow).
• Several natural modes of climate variability have been Several natural modes of climate variability have been identified and described, but their predictability is uncertain.identified and described, but their predictability is uncertain.
• Need to improve understanding of whether and how human Need to improve understanding of whether and how human impacts may alter natural climate variability.impacts may alter natural climate variability.
• Do not yet have confident assessments of the likelihood of Do not yet have confident assessments of the likelihood of abrupt climate changes.abrupt climate changes.
• Insufficient understanding of effects of climate variability Insufficient understanding of effects of climate variability and change on extreme events.and change on extreme events.
• Limited capabilities at regional scales.Limited capabilities at regional scales.• Need better means for identifying, developing, and Need better means for identifying, developing, and
providing climate information required for policy and providing climate information required for policy and resource management decisions.resource management decisions.
Stochastic (Surprises)
Science
Climate System
Knowledge
Human reflexive (volition)
Epistemic (Unknowns)
Non-Scientists
Mac’s Uncertainty Concept Mac’s Uncertainty Concept ModelModel
Decisions
Knowledge
Scientists
communication (translation)
Stochastic (Surprises)
Science
Climate System
Knowledge
Human reflexive (volition)
Epistemic (Unknowns)
Non-Scientists
Mac’s Uncertainty Concept Mac’s Uncertainty Concept ModelModel
Decisions
Knowledge
Scientists
communication (translation)
“To comprehend science as a responsible citizen…both content
and reasoning are essential. The absence of one or the other
may produce laughter, but not good science.”
Paul Gross. Learning Science: Content with Reason. American
Educator Fall 2009: 35-40
Conten
t
Reasonin
g
Surprises
Science
Climate System
Knowledge
Human reflexive (volition)
Unknowns
Non-Scientists
Mac’s Uncertainty Concept Mac’s Uncertainty Concept ModelModel
Decisions
Knowledge
Scientists
communication (translation)
“To comprehend science as a responsible citizen…both
content and reasoning are essential. The absence of one or
the other may produce laughter, but not good science.”
Paul Gross. Learning Science: Content with Reason. American
Educator Fall 2009: 35-40
Conten
t
Reasonin
g
Different Roles of Science in GCC Different Roles of Science in GCC PolicyPolicy
Scientific Knowledge
Politicians
Policy
Pure scientist
Science arbiter
Issue advocate
Honest broker
opinions
Advocacy
Decision making
Policy makers
interpretation
Stakeholders ??
Roger Pielke Jr.
How does science work, How does science work, anyway?anyway?
2. Make an informed
guess about why or
how something
interesting happens
3. Check out how it (our
speculation) stands up
to what we know or what
information we can get
4. Use our judgment whether to (tentatively) accept it, or change, improve or replace it
1. Observe and describe something of interest
Susan Haack
Addressing uncertaintiesAddressing uncertainties
• IdentifyIdentify
• Characterize:Characterize: source, magnitude source, magnitude
• SolicitSolicit expert judgments: level of “confidence” expert judgments: level of “confidence”
• Sensitivity analysisSensitivity analysis: range of probable model outcomes : range of probable model outcomes assessed with model using a range of values various inputs, assessed with model using a range of values various inputs, upper and lower boundupper and lower bound
• Quantify:Quantify: probabilistic analysis (Frequentist and Bayesian), probabilistic analysis (Frequentist and Bayesian), probabilistic distributions, deterministic analysis and hybridsprobabilistic distributions, deterministic analysis and hybrids
• Clarify,Clarify, document range and distributions document range and distributions
• Articulate and communicateArticulate and communicate: probabilistic and scenarios: probabilistic and scenarios
Some predicted impacts of climate Some predicted impacts of climate change?change?
Warmer, dryer summersWarmer, dryer summers Warmer, wetter wintersWarmer, wetter winters Increased spring floodingIncreased spring flooding Changes in sea/lake Changes in sea/lake
levels, water currents, levels, water currents, thermal structurethermal structure
Increased storm Increased storm frequency, severityfrequency, severity
Droughts, crop loss, famineDroughts, crop loss, famine Invasive species, new or re-Invasive species, new or re-
emerging pathogens, parasitesemerging pathogens, parasites More hyperthermia deathsMore hyperthermia deaths Coastal infrastructure/tourismCoastal infrastructure/tourism Habitat damage/lossHabitat damage/loss Loss of biodiversity, extinctions?Loss of biodiversity, extinctions?
DirectIn-direct
Technological advancesTechnological advances Longer growing seasonsLonger growing seasons New agriculture/tourism New agriculture/tourism
opportunities.opportunities. More snow?More snow? Reduced heating costsReduced heating costs Fewer hypothermia deathsFewer hypothermia deaths
GCC heretics, infidels, skeptics, nay-sayers, cynics, GCC heretics, infidels, skeptics, nay-sayers, cynics, deniers??deniers??
What are they What are they really really saying?saying?• Nature: too complex.Nature: too complex.• Conflicting data. Conflicting data. • Models: poor predictors.Models: poor predictors.• Exaggerated impacts.Exaggerated impacts.• Doom/gloom vs. facts.Doom/gloom vs. facts.• Earth’s resiliency.Earth’s resiliency.• Strategies: cost/benefits?Strategies: cost/benefits?• Consensus:Consensus: evidence supports evidence supports
GCCGCC • Less consensus:Less consensus: drivers, drivers,
impacts, strategies, policiesimpacts, strategies, policies
What is the matter with What is the matter with science?science? The debate The debate
continues……continues……• Dyson (1993)
– Consensus: peer pressure (entrepreneurial science) vs. debateConsensus: peer pressure (entrepreneurial science) vs. debate– Public fear drives funding priorities = politicization of sciencePublic fear drives funding priorities = politicization of science– Science's failure to address global welfare vs. unrealistic expectationsScience's failure to address global welfare vs. unrealistic expectations
• Rubin (2001)Rubin (2001)– Science is not the sole repository of the truthScience is not the sole repository of the truth– Little self-limitation on deliverable truthsLittle self-limitation on deliverable truths– Get the facts straight vs. overselling scienceGet the facts straight vs. overselling science– Scientific authority fosters hidden agendas that short-circuit debateScientific authority fosters hidden agendas that short-circuit debate– Participatory decision making impeded by science education shortfalls Participatory decision making impeded by science education shortfalls
• Commoner (1971)Commoner (1971)– Illusion of scientific objectivityIllusion of scientific objectivity
• Grant et al. (2004)Grant et al. (2004)– Popper’s vs. psychological vPopper’s vs. psychological v– Benedikter (2004) basic ideologies and mechanisms not fully visible Benedikter (2004) basic ideologies and mechanisms not fully visible
(psychologically) (psychologically)
• Malnes (2006)Malnes (2006)– Mixed messages: duplicity vs. extraneous diversionsMixed messages: duplicity vs. extraneous diversions
Classical, Modern & Post-Normal Classical, Modern & Post-Normal ScienceScience
the Truth!Classical:
•Observations•Sense experiments•Subjective judgments•Past experience
Absolute
Reductionist, “puzzle-solving”
Modern / Normal:•Exclusive, remote•Non-interdisciplinary•Experiments/models•Data analysis/interpretation•Hypothesis testing
•predictions •probabilities•possible explanations •disconnected policy•adversarial•communication gaps
“Post-Normal”•Inclusive•Natural & social sciences•Complexity/risk/urgency•Systems approach•Cost/benefits•Public debate
Precautionary, risk management
•shared decision making•problems solving •confidence/trust building•Anti-science perception
Classical, Modern & Post-Normal Classical, Modern & Post-Normal ScienceScience
the Truth!Classical:
•Observations•Sense experiments•Subjective judgments•Past experience
Absolute
Reductionist, “puzzle-solving”
Modern / Normal:•Exclusive, remote•Non-interdisciplinary•Experiments/models•Data analysis/interpretation•Hypothesis testing
•predictions •probabilities•possible explanations •disconnected policy•adversarial•communication gaps
“Post-Normal”•Inclusive•Natural & social sciences•Complexity/risk/urgency•Systems approach•Cost/benefits•Public debate
Precautionary, risk management
•shared decision making•problems solving •confidence/trust building•Anti-science perception
Perceptions of Perceptions of ScienceScience
God-like? Elitist? Crusading knight? Mad/evil?
Two Opposing Metaphors for Two Opposing Metaphors for Science: Science: God-likeGod-like or or GolemGolem??
• ““Ultimate source of Ultimate source of knowledge/wisdom.knowledge/wisdom.
• Operates in unencumbered, controlled Operates in unencumbered, controlled environment.environment.
• Strives for perfection.Strives for perfection.• Accountable, held to high standard.Accountable, held to high standard.
• A creature of our own design, neither good or A creature of our own design, neither good or bad. bad.
• Powerful, protective, follows orders. Powerful, protective, follows orders. • Clumsy and dangerous, must be controlled. Clumsy and dangerous, must be controlled. • Fallible = low expectations. Fallible = low expectations. • Can’t be blamed for mistakes if it is trying.Can’t be blamed for mistakes if it is trying.
Truth
The Snowball The Snowball EffectEffect
Climate Science Uncertainties
“Other” Uncertainties
Cascading Uncertainties in Climate Cascading Uncertainties in Climate ScienceScience
Emission scenarios
Carbon cycle response
Global climate
sensitivity
Regional climate change
scenarios
Range of possible impacts
Adapted from Schneider 1983
Scientists face important challenges in Scientists face important challenges in communicating science to non-scientistscommunicating science to non-scientists
• The nature of ‘normal’ scientific investigation and The nature of ‘normal’ scientific investigation and debatedebate– logic vs. cognitive processeslogic vs. cognitive processes– adversarial, not focused on consensus developmentadversarial, not focused on consensus development– debate primarily within disciplinesdebate primarily within disciplines
• IsolationismIsolationism– ““too busy” to talk to non-scientists!too busy” to talk to non-scientists!– rift between physical and social scientistsrift between physical and social scientists
• Inadequate training in communication skillsInadequate training in communication skills– dealing with mediadealing with media– addressing misinformationaddressing misinformation– understanding policy development processunderstanding policy development process
Can complex science be understood by the Can complex science be understood by the public?public?
• Yes, many successful examples !Yes, many successful examples !
• Knowledge from Scientific process Knowledge from Scientific process
• ““Step-back”, discuss and debunk science Step-back”, discuss and debunk science mythsmyths– Myth 1: science as a collection of established factsMyth 1: science as a collection of established facts– Myth 2: conflicting science presented in a Myth 2: conflicting science presented in a
balanced waybalanced way– Myth 3: science jargon as chief obstacleMyth 3: science jargon as chief obstacle
Interpretations of Global Climate Interpretations of Global Climate Science UncertaintiesScience Uncertainties• Scientists:Scientists:
intrinsic part of scienceintrinsic part of science too many variables to eliminatetoo many variables to eliminate can be reduced with more scientific informationcan be reduced with more scientific information general support of a general support of a ““precautionary” approach”.precautionary” approach”.
• Policymakers:Policymakers: science is sloppyscience is sloppy ““burden of proof”burden of proof” lack of/incomplete knowledge = bad sciencelack of/incomplete knowledge = bad science must have all the facts: decision making/policy must have all the facts: decision making/policy
implementation implementation little/no support of precautionary stepslittle/no support of precautionary steps
The Climate Uncertainty The Climate Uncertainty “Toolbox”“Toolbox”
Permutation
tests
Bootstrapping
Resampling
Stochastic models
Monte
Carlo
Bayesian
statisticsJackknife
Deterministic
models
Neural
networks
Fisherian statistics
Climate models
Likelihood-based
approaches
Scenario analysis
Communicating Uncertainties of Climate Communicating Uncertainties of Climate ChangeChange
• Increase science literacyIncrease science literacy
• Outreach materials: Hypothetical scientific investigations.Outreach materials: Hypothetical scientific investigations.
• Develop vivid narratives of potential harmDevelop vivid narratives of potential harm
• Address/communicate uncertainties to stakeholder communities.Address/communicate uncertainties to stakeholder communities.
• Understand decision making mechanics, assess values and Understand decision making mechanics, assess values and attitudesattitudes
• Develop an integrative (social-natural science), participatory Develop an integrative (social-natural science), participatory decision-making processdecision-making process
• Psychometric paradigm: people (focus on a range of qualitatively Psychometric paradigm: people (focus on a range of qualitatively distinctive factors that are irreducible by numbers) show a richer distinctive factors that are irreducible by numbers) show a richer rationality than experts (focus on quantity), risk perception in rationality than experts (focus on quantity), risk perception in social sciences, used to explain divergence between risk related social sciences, used to explain divergence between risk related judgmentsjudgments
• People influenced by whether risk is catastrophic , future People influenced by whether risk is catastrophic , future generations, involuntary incurred, , uncontrollable, delayed vs generations, involuntary incurred, , uncontrollable, delayed vs immediate, and particularly dreaded.immediate, and particularly dreaded.
Cass Sustein 2007: Columbia Law Review 107: 503-557
What are the likely climate changes What are the likely climate changes over the next century, or so??over the next century, or so??
• Most global warming projections are for a 4-10 F Most global warming projections are for a 4-10 F increase by 2100increase by 2100
• Virtually certain:Virtually certain: ~ ~ 95 to 100%95 to 100% – Warmer days and nights, fewer cold periods over most land Warmer days and nights, fewer cold periods over most land
areasareas
• Very likely: Very likely: ~ 67-95%~ 67-95%– Warm spells/heat waves, frequency increasing over most land Warm spells/heat waves, frequency increasing over most land
areasareas– Heavy and more frequent precipitation eventsHeavy and more frequent precipitation events
• Likely:Likely: ~ 33-67%~ 33-67%– Area affected by drought increasesArea affected by drought increases– Intense tropical cyclone activity increasesIntense tropical cyclone activity increases– Increased incidence of extreme high sea level (exclude Increased incidence of extreme high sea level (exclude
tsunamis)tsunamis)
Communicating Uncertainty:Communicating Uncertainty:Examples from Weather ForecastsExamples from Weather Forecasts
• Numerical probabilities:Numerical probabilities: – A 30 % chance of rain.A 30 % chance of rain.
• Qualitative or categorical forecastsQualitative or categorical forecasts:: – Today’s weather will be “fine”.Today’s weather will be “fine”.
Handmer et al. 2007
Communicating Uncertainty:Communicating Uncertainty:Examples from Weather Examples from Weather
ForecastsForecasts• Numerical probabilities:Numerical probabilities:
– high likelihood, tangible events high likelihood, tangible events – can be misinterpreted: where? when? how can be misinterpreted: where? when? how
long?long?– example: 30% chance of rainexample: 30% chance of rain
• a 30% chance of rain in the forecast area.a 30% chance of rain in the forecast area.• a 30% chance of rain at a specific location in forecast a 30% chance of rain at a specific location in forecast
area.area.• only 30% of the forecast area will be affected, if it does only 30% of the forecast area will be affected, if it does
rain.rain.• it will rain 30% of the day.it will rain 30% of the day.• it will rain 3 out of 10 days when rain is forecastedit will rain 3 out of 10 days when rain is forecasted
– not useful when:not useful when:• i.e. 0.0001% chance of as a severe event i.e. 0.0001% chance of as a severe event • Abstract, “invisible”, even catastrophic eventsAbstract, “invisible”, even catastrophic events• Public more concerned with issues of control, trust and Public more concerned with issues of control, trust and
equityequityHandmer et al. 2007
Decision-making Under Decision-making Under UncertaintyUncertainty
Decisions:Decisions: • based on likelihood of uncertain eventsbased on likelihood of uncertain events
– Uncertainties expressedUncertainties expressed• numerical form (odds) numerical form (odds) • subjective probabilistic statementssubjective probabilistic statements
• heuristicsheuristics– RepresentativenessRepresentativeness – degree of relationship, causality – degree of relationship, causality– Availability Availability – ease of instances/consequences imagined– ease of instances/consequences imagined– Adjustment/AnchoringAdjustment/Anchoring –initial value adjusted to yield final –initial value adjusted to yield final
answer (problem formulation or partial computation)answer (problem formulation or partial computation)
Tversky, A. and D. Kahneeman. (1974). Judgment under Uncertainty: Heuristics and Biases. Science 185: 1124-1131
Decision-making Under Decision-making Under UncertaintyUncertainty
• Task of choiceTask of choice– Framing Framing
• Relate decision making to similar problemsRelate decision making to similar problems• Used to determine outcome loss or gainsUsed to determine outcome loss or gains
– EvaluationEvaluation• Act to reduce loss probability, maximize gainsAct to reduce loss probability, maximize gains• Adopt risk averse stanceAdopt risk averse stance
• 3 subconscious processes 3 subconscious processes (heuristics)(heuristics):: – RepresentativenessRepresentativeness – degree of relationship, causality – degree of relationship, causality– Availability Availability – ease of instances/consequences imagined– ease of instances/consequences imagined– Adjustment/AnchoringAdjustment/Anchoring –initial value adjusted to yield final –initial value adjusted to yield final
answer (problem formulation or partial computation)answer (problem formulation or partial computation)
Patt, A. and S. Dessai. (2005). Communicating Uncertainty: lessons learned and suggestions for climate change assessment. C. R. Geoscience 337: 425-441
Tversky, A. and D. Kahneeman. (1974). Judgment under Uncertainty: Heuristics and Biases. Science 185: 1124-1131
Decision-making Under Decision-making Under UncertaintyUncertainty
• Stochastic uncertainties Stochastic uncertainties (unpredictability/surprises)(unpredictability/surprises)– Framing: (usually) in frequentist termsFraming: (usually) in frequentist terms– Uncertainty: probability expressed relative frequenciesUncertainty: probability expressed relative frequencies– Heuristic:Heuristic: Availability Availability = analogy = analogy– Evaluation: Less risk averse, under-estimate risk, less prone Evaluation: Less risk averse, under-estimate risk, less prone
to illogical choiceto illogical choice• Epistemic uncertaintiesEpistemic uncertainties (structural/ignorance)(structural/ignorance)
– Framing (often) in Bayesian termsFraming (often) in Bayesian terms– Uncertainties: ambiguous probability estimates, numerical Uncertainties: ambiguous probability estimates, numerical
ranges confidence, expert opinionranges confidence, expert opinion– Heuristic: Heuristic: RepresentativenessRepresentativeness = common, familiarity= common, familiarity – Evaluation: More risk averse, over-estimate risk, more prone Evaluation: More risk averse, over-estimate risk, more prone
to logic errorsto logic errors
Patt, A. and S. Dessai. (2005). Communicating Uncertainty: lessons learned and suggestions for climate change assessment. C. R. Geoscience 337: 425-441
Tversky, A. and D. Kahneeman. (1974). Judgment under Uncertainty: Heuristics and Biases. Science 185: 1124-1131
Decision-making Under Decision-making Under UncertaintyUncertainty
Decisions:Decisions: • based on likelihood of uncertain eventsbased on likelihood of uncertain events
– Uncertainties expressedUncertainties expressed• numerical form (odds) numerical form (odds) • subjective probabilistic statementssubjective probabilistic statements
• heuristicsheuristics– RepresentativenessRepresentativeness – degree of relationship, causality – degree of relationship, causality– Availability Availability – ease of instances/consequences imagined– ease of instances/consequences imagined– Adjustment/AnchoringAdjustment/Anchoring –initial value adjusted to yield final –initial value adjusted to yield final
answer (problem formulation or partial computation)answer (problem formulation or partial computation)
Tversky, A. and D. Kahneeman. (1974). Judgment under Uncertainty: Heuristics and Biases. Science 185: 1124-1131
Graphical
Communication of
Uncertain Quantiti
es
to Non-Technical
People
Risk Analysis 7 (4)
Ibrekk et a
l. 1987
*
9 graphical representations of the same snow fall predictions
*
Communicating Uncertainty:Communicating Uncertainty:Examples from Weather ForecastsExamples from Weather Forecasts
• Qualitative or categorical forecastsQualitative or categorical forecasts:: – ““Fine”Fine”– Also misinterpreted: does it meanAlso misinterpreted: does it mean
• No rain?No rain?
• Sunny/sunshine?Sunny/sunshine?
• Not too hot/moderate temperature?Not too hot/moderate temperature?
• Clear day/ not cloudy or overcast?Clear day/ not cloudy or overcast?
• Lovely weather/a nice day?Lovely weather/a nice day?
• No wind/light winds?No wind/light winds?
• Some cloud/may be overcast?Some cloud/may be overcast?
Handmer et al. 2007
Communicating Uncertainty:Communicating Uncertainty:When Uncertainties are InsurmountableWhen Uncertainties are Insurmountable
• ScenariosScenarios– Coherent, plausible, alternative representations of future Coherent, plausible, alternative representations of future
climateclimate– Projections/modeled responses (not forecasts) from climate Projections/modeled responses (not forecasts) from climate
“drivers”.“drivers”.– Descriptions: current states, drivers, step-wise changes, Descriptions: current states, drivers, step-wise changes,
future images.future images.– Assessments future climate conditions (very high Assessments future climate conditions (very high
uncertainties).uncertainties).– Assist in designing adaptation/mitigation strategiesAssist in designing adaptation/mitigation strategies– Provide better understanding of interactions/dynamicsProvide better understanding of interactions/dynamics
Outreach: Uncertainties of Climate ChangeOutreach: Uncertainties of Climate Change
• Increase science literacyIncrease science literacy
• vivid narratives of potential harm/benefitsvivid narratives of potential harm/benefits
• Communicate uncertainties to stakeholder communities.Communicate uncertainties to stakeholder communities.
• Assess values and attitudesAssess values and attitudes
• Develop an integrative (social-natural science) decision-making Develop an integrative (social-natural science) decision-making processprocess
• Psychometric paradigm: people (focus on a range of Psychometric paradigm: people (focus on a range of qualitatively distinctive factors that are irreducible by qualitatively distinctive factors that are irreducible by numbers) show a richer rationality than experts (focus on numbers) show a richer rationality than experts (focus on quantity), risk perception in social sciences, used to explain quantity), risk perception in social sciences, used to explain divergence between risk related judgmentsdivergence between risk related judgments
• People influenced by whether risk is catastrophic , future People influenced by whether risk is catastrophic , future generations, involuntary incurred, , uncontrollable, delayed vs generations, involuntary incurred, , uncontrollable, delayed vs immediate, and particularly dreaded.immediate, and particularly dreaded.
An Interesting Expert Opinion: An Interesting Expert Opinion: An Essay: Divergent American Reactions to Terrorism An Essay: Divergent American Reactions to Terrorism and Climate Changeand Climate Change
Terrorism:Terrorism:
• low probability, palpable, catastrophiclow probability, palpable, catastrophic• risks are immediate, short term risks are immediate, short term • Concern to US, Britain an allies. Concern to US, Britain an allies. • Perceived high risk recurrence Perceived high risk recurrence • neglect probability visual anger, fear, neglect probability visual anger, fear, • Huge costs justified to protect Huge costs justified to protect
national security benefits unimportant national security benefits unimportant • 2005-2006: $255 $318 billion 2005-2006: $255 $318 billion
committed to war on terror vs $312 committed to war on terror vs $312 billion for entire Kyoto protocol. billion for entire Kyoto protocol.
• Public opinion Public opinion – 2004 48% Britons: top global priority 2004 48% Britons: top global priority – 2006 80% Americans top global 2006 80% Americans top global
prioritypriority
Climate change:Climate change: • high probability, impalpable, high probability, impalpable,
catastrophiccatastrophic• Long-term risk, affect future Long-term risk, affect future
generations. generations. • Concern to other nations only Concern to other nations only • serious mitigative/adaptive action serious mitigative/adaptive action
unlikleyunlikley• climate change causes obscure climate change causes obscure
(uncertainties) (uncertainties) • people lack experience make risks people lack experience make risks
apparent, real or impending, apparent, real or impending, • cost benefits, cost benefits, • Public opinion Public opinion
– 2000 CC: ranked environment as 162000 CC: ranked environment as 16thth most important issue and 12most important issue and 12thth out of 13 out of 13 top environmental problems top environmental problems
– 2004: 63% Britons: top global 2004: 63% Britons: top global environmental issue.environmental issue.
Cass Sustein 2007: Columbia Law Review 107: 503-557
Similarities: potentially catastrophic outcomes, difficulty assigning probabilities to risks
Divergence: simple facts and political responses to each risk:
“We have to deal with this new type of threat [terrorism] in a new way we haven’t yet defined.. With a low-probability, high impact event like this.. if there is a 1% chance that Pakistani nuclear scientists are helping Al Qaeda build or develop a nuclear weapon, we have to treat it as a certainty in terms of our response” -- Dick Cheney, Former Vice-President
“Climate change is the most severe problem we are facing today - more serious than the threat from terrorism” – Sir David King Director, Smith School of Environment, Oxford; Research Director, Dept. of Physical Chemistry, Cambridge; Former Chief Scientific Advisor to Blair Administration.
An Interesting Expert Opinion: An Interesting Expert Opinion: An Essay: Divergent American Reactions to Terrorism An Essay: Divergent American Reactions to Terrorism
and Climate Changeand Climate ChangeCass Sustein 2007: Columbia Law Review 107: 503-557
“Any philosophy that in its quest for certainty ignores the reality of the uncertain in the ongoing processes of nature, denies the conditions out of which it arises.”
John Dewey, The Quest for Certainty, 1929
EpiloguEpiloguee
And now, the punch line(s)And now, the punch line(s)…………
• Climate change uncertainties: tremendous outreach Climate change uncertainties: tremendous outreach challengeschallenges
• Uncertainties are cumulative: science to policy Uncertainties are cumulative: science to policy
• Climate change predictions: probabilistic context where Climate change predictions: probabilistic context where possible.possible.
• Scenarios: address insurmountable uncertainties.Scenarios: address insurmountable uncertainties.
• Integrative natural and social science approach to Integrative natural and social science approach to decision-making.decision-making.
• Outreach: science mechanics, sources of uncertainty, Outreach: science mechanics, sources of uncertainty, restore faith in science, assess/understand heuristics, restore faith in science, assess/understand heuristics, facilitate improved decision-making, craft a responsible, facilitate improved decision-making, craft a responsible, informative and useful message.informative and useful message.