Extreme Heat and Human Health

Richard B. Rood and Marie S. O’Neill

Richard B. Rood734-647-3530

rbrood@umich.eduhttp://aoss.engin.umich.edu/people/rbrood

December 17, 2010

Funding Acknowledgments

• Reducing social disparities of heatwaves impacts in a changing climate– Grant from Centers for Disease Control and Prevention (Sept. 2008-

August 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.– 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

SUN

WATER

Ability to Cool

HEAT STRESS

Schematic of System

SUN

WATER

Ability to Cool

HEAT STRESS

Built EnvironmentAmplificationAccumulation

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

Persistent Daily Lows

Incorporation of humidity (apparent T)

Incorporation of clouds, wind, etc.

Strenuous exertionRegionalAcclimation

Accumulated HeatBuilt Environment

Ability to coolSultrinessDehydration

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)

Exposure (Crossing the border)

Urban Heat

Compromised Health

High temperature

High temperatureLow temperature

Built environmentAccumulated heatHot buildings

High temperatureAccumulated heatInability to cool

Urban HeatBuilt environmentAccumulated heatHot buildings

Compromised HealthHigh temperatureAccumulated heatInability to cool

Quantitative Analysis Detroit

Oswald et al. (2010) J. Appl. Meteor. Clim. (submitted)Zhang et al. (2010) Environmental Research (submitted)

Imperviousness built environment best predictor

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:– 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.– Learning the language– Learning the priorities– Learning the compromises– Learning the possibilities