December 17, 2010
Extreme Heat and Human Health
Richard B. Rood and Marie S. O’Neill
Richard B. Rood
734-647-3530
rbrood@umich.edu
http://aoss.engin.umich.edu/people/rbrood
Funding Acknowledgments
• Reducing social disparities of heatwaves impacts in a
changing climate
– Grant from Centers for Disease Control and Prevention (Sept. 2008August 2011), Grant R18 EH000348-01
– Investigators: M. O’Neill, E. Parker, R. Rood (U of Michigan); S.
McCormick (George Washington U.); M. Stults, X. Manarolla (ICLEI:
Local Governments for Sustainability); J. Schwartz and A. Zanobetti
(Harvard U); K. Ebi (ESS/LLC)
• Climate change, heatwaves, and health: Local tools for
sustainability, equity, and prevention
– Grant from Graham Environmental Sustainability Institute, University
of Michigan, (2008-2010)
http://www.provost.umich.edu/gesi/funding/esmrt_2008-1.html
– Investigators: M. O’Neill, R. Rood, E. Parker, D. Brown
Approach of this study
• A team of people with a range of skill sets
and interests
– Epidemiology
– Environmental health
– Health behavior and social science
– Geographical information
– Statistical analysis
– Meteorology
– Systems analysis
What do we want to tell a union of geophysicists?
• What does the problem-solving space look
like?
• Where does physical climate sit in relation
to other elements of the problem?
Background: Extreme heat is already a problem
• Extreme heat impacts human health, and more
deaths are attributed to heat than any other
environmental parameter.
• Relation between heat and impact on health is
difficult to quantify.
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Physics of heating and cooling
Attributes of local environment
Physiology of individuals / acclimation
Attributes of personal environment
• In fact, extreme heat that impacts health is hard
to define.
– Sheridan and Kalkstein (2004)
– EPA Guidebook
Extreme Heat and Climate Change
• There is observational evidence of increasing
episodes of extreme heat (for example, Gaffen
and Ross, Nature, 1998)
• There are predictions of increases in extreme
heat events by climate change projections (for
example, Meehl and Tebaldi, 2004)
• See IPCC, 2007 for a more complete
assessment.
• Climate projections do not necessarily link to
human health.
How do we use this information in a public
health application?
• Consider another form of model study (Diffenbaugh and
Ashfaq, 2010)
– Using a regional climate model resolving North America they
focus on the next 30 years.
– This period is expected to be well below the putative dangerous
climate change threshold of a 2° C
– What is the change in events that look like historical heat waves
in the next 30 years?
– Result: In 2030-2039 see 6 extreme events per decade as
compared with ~ 1 per decade in 1950-1990. Heat risk, potential
danger to human health increases, even if there is aggressive
adoption of mitigation policies.
See Philo. Trans. Roy. Soc., Jan 2011 (4 degrees warming)
Schematic of System
Ability to Cool
SUN
HEAT STRESS
WATER
Schematic of System
Ability to Cool
SUN
HEAT
WATER
STRESS
Built Environment
Amplification
Accumulation
Rational Paths of Using this Information
Calculation of parameters that link heat to human health.
Persistent Daily Highs
Persistent Daily Lows
Incorporation of humidity (apparent T)
Incorporation of clouds, wind, etc.
Paths of better defining “heat extremes”
Persistent Daily Highs
Strenuous exertion
Regional
Acclimation
Persistent Daily Lows
Accumulated Heat
Built Environment
Incorporation of humidity (apparent T)
Ability to cool
Sultriness
Dehydration
Incorporation of clouds, wind, etc.
Information?
Improved representations of heat and humans
• Can we do better than just saying that it is going
to get hotter?
• What is value of nuanced calculations of heat
extremes and stress? Is it usable information?
• What is the balance between having to study
each case and the ability to aggregate
information and develop general strategies?
• What is the minimal level of complexity that must
be accommodated?
Rational Paths of Using this Information
Consideration of people who get in trouble when it is hot.
Exertion
Exposure
Urban Heat
Compromised Health
Paths of considering how people get in trouble
Exertion (August football)
High temperature
Exposure (Crossing the border)
High temperature
Low temperature
Urban Heat
Built environment
Accumulated heat
Hot buildings
Compromised Health
High temperature
Accumulated heat
Inability to cool
Quantitative Analysis Detroit
Imperviousness 
built environment 
best predictor
Oswald et al. (2010) J. Appl. Meteor. Clim. (submitted)
Zhang et al. (2010) Environmental Research (submitted)
Rational Paths of Using this Information
Identification of vulnerable people and reducing the risk
Population Characterization
Warning
Education of Public/First Providers
Adaptive Capacity/Design
Summary: Heat, Humans, Climate Change
• Extreme heat is already an important public
health risk.
• Projections of future heat events that are similar
to dangerous heat events of the past suggest
increased risk.
• Increase in temperature does not easily transfer
over to actionable information by public health
officials.
Summary: Heat, Humans, Climate Change
• Important considerations for making climate information more
relevant to human health
– Persistence of hot spells
• Daily lows and highs
• Accumulation of heat
– Overlap with cities and built environment
– Thresholds related to physiology
– Extension of heat threats to cities and regions where heat-related risk is
unexpected.
• Responses:
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Education of at risk public \ What to do
Education of first responders
City planning
Materials
Summary: Take Away Message
• Responses to address extreme heat de-correlates the
details of the physical science from solution.
• It is important to identify regions, hence cities, where
heat is likely to become a risk.
• The cogeneration of knowledge by all disciplines
represented on the team contribute to successful
solutions.
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Learning the language
Learning the priorities
Learning the compromises
Learning the possibilities