Darren Ruddell

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Scales of Perception Public Awareness of
Regional and Neighborhood Climate Change

• Darren Ruddell
• Arizona State University
• American Meteorological Society
• Urban Implications of Climate Change and
  Population Growth
• 15 January 2009

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Research Themes

• General
• -Changing urban climates and heat-related hazards

• Case Studies
• -Exposure to extreme heat
• -Perceptions of climate change

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Presentation Outline

• Extreme Heat and Health
• Temperature Trends
• Constructing Environmental Perception
• Mixed Method Analysis
• Conclusions about Climate Change

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Extreme Heat and Health
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Global and Local Temperature Composition
Global Trends
Local Trends
2 m Air Temperature Simulations Grossman-Clarke
Temperature Change 1970-2004 IPCC 2007
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Constructing Environmental Perception
Social Frames of Reference
Experience
Aitken et al. 1989 Garcia-Mira et al. 2005
Uzzell 2000
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Heterogeneous Phoenix Heat Island
Temperature (C)
Simulated Air Temperature 1km spatial resolution,
July 17 2005
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Research Questions

• Is the correspondence between social perceptions
  and environmental conditions weaker or stronger
  at finer spatial resolutions in the current
  study?
• What is the relative importance of localized
  temperature experience and broader social frames
  of reference in predicting residents perceptions
  of temperature in the urbanized area?

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Data Sources and Methodology

• Temperature
• Weather Research and Forecast (WRF) climate model
• Social Perceptions
• Phoenix Area Social Survey (PASS) 2006
• N 808
• Demographics
• Census Block Group (2000)

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Weak Association between Perceptions and Physical
Conditions at Regional Scale
Spearmans rho 0.262 Sig 0.102
Average Perceived Temp in Valley Over Time
Aggregated by Nhood
Source PASS 2006 WRF Simulation Scale 1) Not
hotter 2) A little hotter 3) A lot hotter
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Strong Association between Perceptions and
Physical Conditions at Local Scale
Spearmans rho 0.606 Sig 0.001
Average Perceived Temp in Nhood Compared to
Other Valley Nhoods
Source PASS 2006 WRF Simulation Scale 1) A lot
cooler . . . 5) A lot hotter
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Social Variables Explain Perceived Temperature at
Metropolitan Scale
Perceived Temp in Region Over Time
Independent Variables B Wald Sig
Age 0.095 4.936 0.026
Ethnicity (minority) 0.650 4.605 0.032
Gender (female) 0.790 10.297 0.001
Politically Moderate -0.307 0.883 0.347
Politically Conservative -0.694 4.917 0.027
Income (log) -0.734 2.476 0.116
Time Away summer 2005 0.056 0.059 0.808
Illness (yes) 0.664 6.006 0.014
Residency 0.014 3.206 0.073
Mean Low Nhood Temp -0.005 0.002 0.963
Results Multinomial Logistic Regression Reference
Category Not hotter Output A lot hotter
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Exposure Overwhelms Social Variables at Local
Scale
Perceived Nhood Temp Relative to Others
Independent Variables Est Wald Sig
Age 0.028 1.007 0.316
Ethnicity (minority) -0.278 1.970 0.160
Gender (female) 0.089 0.317 0.573
Politically Moderate 0.212 1.122 0.289
Politically Conservative 0.028 0.022 0.883
Income (log) -0.371 1.558 0.212
Time Away summer 2005 0.393 6.817 0.009
Illness (yes) 0.092 0.281 0.596
Residency -0.007 2.127 0.145
Mean Low Nhood Temp 0.457 41.912 0.000
Results Ordinal Regression
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Conclusion of Study

• Significant differences in perceived and
  simulated temperatures among study sites
• Public perceptions of temperature vary by spatial
  scale
• People can perceive climate change when they
  experience it in their daily lives
• Perceptions become increasingly distorted as
  spatial scales broadens

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Future Research

• Heat Warning Systems
• Human Health and Extreme Heat
• Water Resource Management
• Policy Initiatives

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Collaborators

• Sharon Harlan, Susanne Grossman-Clarke, Gerardo
  Chowell
• NSF Grants
• SES 0216281, DEB 0423704, DGE 9987612

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Questions?