Global Climate ChanGe and extreme Weather events Understanding the Contributions to infectious disease emergence

Global Climate Change and Extreme Weather
Events: Understanding the Contributions to
Infectious Disease Emergence: Workshop Summary
David A. Relman, Margaret A. Hamburg, Eileen R.
Choffnes, and Alison Mack, Rapporteurs, Forum on
Global Health
ISBN: 0-309-12403-4, 304 pages, 6 x 9, (2008)
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Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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Global Climate Change and
Extreme Weather Events
Understanding the Contributions to Infectious Disease Emergence
W o r k s h o p Su m m a r y

Rapporteurs: David A. Relman, Margaret A. Hamburg,
Eileen R. Choffnes, and Alison Mack

Forum on Microbial Threats
Board on Global Health

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Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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Suggested citation: IOM (Institute of Medicine). 2008. Global climate change and extreme
weather events: understanding the contributions to infectious disease emergence. Washington, DC: The National Academies Press.

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Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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FORUM ON MICROBIAL THREATS
DAVID A. RELMAN (Chair), Stanford University, Palo Alto, California
MARGARET A. HAMBURG (Vice Chair), Nuclear Threat Initiative/Global
Health & Security Initiative, Washington, DC
DAVID W. K. ACHESON, Center for Food Safety and Applied Nutrition, Food
and Drug Administration, Rockville, Maryland
RUTH L. BERKELMAN, Emory University, Center for Public Health
Preparedness and Research, Rollins School of Public Health, Atlanta, Georgia
ENRIQUETA C. BOND, Burroughs Wellcome Fund, Research Triangle Park,

North Carolina
ROGER G. BREEZE, Centaur Science Group, Washington, DC
STEVEN J. BRICKNER, Pfizer Global Research and Development, Pfizer Inc.,
Groton, Connecticut
GAIL H. CASSELL, Eli Lilly & Company, Indianapolis, Indiana
BILL COLSTON, Lawrence Livermore National Laboratory, Livermore,
California
RALPH L. ERICKSON, Global Emerging Infections Surveillance and
Response System, Department of Defense, Silver Spring, Maryland
MARK B. FEINBERG, Merck Vaccine Division, Merck & Co., West Point,
Pennsylvania
J. PATRICK FITCH, National Biodefense Analysis and Countermeasures
Center, Frederick, Maryland
DARRELL R. GALLOWAY, Medical S&T Division, Defense Threat
Reduction Agency, Fort Belvoir, Virginia
S. ELIZABETH GEORGE, Biological and Chemical Countermeasures
Program, Department of Homeland Security, Washington, DC
JESSE L. GOODMAN, Center for Biologics Evaluation and Research, Food
and Drug Administration, Rockville, Maryland
EDUARDO GOTUZZO, Instituto de Medicina Tropical–Alexander von
Humbolt, Universidad Peruana Cayetano Heredia, Lima, Peru
JO HANDELSMAN, College of Agricultural and Life Sciences, University of
Wisconsin, Madison
CAROLE A. HEILMAN, Division of Microbiology and Infectious Diseases,
National Institute of Allergy and Infectious Diseases, National Institutes of
Health, Bethesda, Maryland
DAVID L. HEYMANN, Polio Eradication, World Health Organization,
Geneva, Switzerland
PHIL HOSBACH, New Products and Immunization Policy, Sanofi Pasteur,
Swiftwater, Pennsylvania

IOM Forums and Roundtables do not issue, review, or approve individual documents. The responsibility for the published workshop summary rests with the workshop rapporteur(s) and the institution.



Copyright © National Academy of Sciences. All rights reserved.


Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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JAMES M. HUGHES, Global Infectious Diseases Program, Emory
University, Atlanta, Georgia
STEPHEN A. JOHNSTON, Arizona BioDesign Institute, Arizona State
University, Tempe
GERALD T. KEUSCH, Boston University School of Medicine and Boston
University School of Public Health, Massachusetts
RIMA F. KHABBAZ, National Center for Preparedness, Detection and Control
of Infectious Diseases, Centers for Disease Control and Prevention, Atlanta,
Georgia
LONNIE J. KING, Center for Zoonotic, Vectorborne, and Enteric Diseases,
Centers for Disease Control and Prevention, Atlanta, Georgia
GEORGE W. KORCH, U.S. Army Medical Research Institute for Infectious
Diseases, Fort Detrick, Maryland
JOSHUA LEDERBERG,* The Rockefeller University, New York
STANLEY M. LEMON, School of Medicine, University of Texas Medical
Branch, Galveston
LYNN G. MARKS, Medicine Development Center, GlaxoSmithKline,
Collegeville, Pennsylvania
EDWARD MCSWEEGAN, National Institute of Allergy and Infectious
Diseases, National Institutes of Health, Bethesda, Maryland

STEPHEN S. MORSE, Center for Public Health Preparedness, Columbia
University, New York
MICHAEL T. OSTERHOLM, Center for Infectious Disease Research and
Policy, School of Public Health, University of Minnesota, Minneapolis
GEORGE POSTE, Arizona BioDesign Institute, Arizona State University, Tempe
GARY A. ROSELLE, Central Office, Veterans Health Administration,
Department of Veterans Affairs, Washington, DC
JANET SHOEMAKER, Office of Public Affairs, American Society for
Microbiology, Washington, DC
P. FREDERICK SPARLING, University of North Carolina, Chapel Hill
BRIAN J. STASKAWICZ, Department of Plant and Microbial Biology,
University of California, Berkeley
TERENCE TAYLOR, International Council for the Life Sciences,
Washington, DC
MURRAY TROSTLE, U.S. Agency for International Development,
Washington, DC
Staff
EILEEN CHOFFNES, Director
KATE SKOCZDOPOLE, Senior Program Associate
SARAH BRONKO, Senior Program Assistant
ALISON MACK, Science Writer
*Deceased February 2, 2008.

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Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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BOARD ON GLOBAL HEALTH
Margaret Hamburg (chair), Consultant, Nuclear Threat Initiative,
Washington, DC
George Alleyne, Director Emeritus, Pan American Health Organization,
Washington, DC
Donald Berwick, Clinical Professor of Pediatrics and Health Care Policy,
Harvard Medical School, and President and Chief Executive Officer,
Institute of Healthcare Improvement, Boston, Massachusetts
Jo Ivey Boufford (IOM Foreign Secretary), President, New York Academy of
Medicine, New York
David R. Challoner, Vice President for Health Affairs, Emeritus, University of
Florida, Gainesville
Ciro de Quadros, Albert B. Sabin Vaccine Institute, Washington, DC
Sue Goldie, Associate Professor of Health Decision Science, Department
of Health Policy and Management, Center for Risk Analysis, Harvard
University School of Public Health, Boston, Massachusetts
Richard Guerrant, Thomas H. Hunter Professor of International Medicine
and Director, Center for Global Health, University of Virginia School of
Medicine, Charlottesville
Gerald T. Keusch, Assistant Provost for Global Health, Boston University
School of Medicine, and Associate Dean for Global Health, Boston
University School of Public Health, Massachusetts
Jeffrey Koplan, Vice President for Academic Health Affairs, Emory
University, Atlanta, Georgia
Sheila Leatherman, Research Professor, University of North Carolina School of
Public Health, Chapel Hill
Michael Merson, Director, Duke Global Health Institute, Duke University,
Durham, North Carolina
Mark L. Rosenberg, Executive Director, Task Force for Child Survival and
Development, Emory University, Decatur, Georgia

Philip Russell, Professor Emeritus, Bloomberg School of Public Health, Johns
Hopkins University, Baltimore, Maryland
Staff
Patrick Kelley, Director
Allison Brantley, Senior Program Assistant
IOM boards do not review or approve individual reports and are not asked to endorse conclusions
and recommendations. The responsibility for the content of the report rests with the authors and the
institution.

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Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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Copyright © National Academy of Sciences. All rights reserved.


Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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Reviewers

This report has been reviewed in draft form by individuals chosen for their
diverse perspectives and technical expertise, in accordance with procedures
approved by the National Research Council’s Report Review Committee. The
purpose of this independent review is to provide candid and critical comments
that will assist the institution in making its published report as sound as possible
and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The review comments and draft
manuscript remain confidential to protect the integrity of the deliberative process.

We wish to thank the following individuals for their review of this report:
Ralph L. Erickson, DoD-Global Emerging Infections Surveillance and
Response System, Walter Reed Army Institute of Research
Jonathan Patz, Center for Sustainability and the Global Environment,
University of Wisconsin-Madison
Jeffrey Shaman, College of Oceanic and Atmospheric Sciences, Oregon
State University
Mark Wilson, Department of Epidemiology, The University of Michigan
Mary Wilson, Department of Population and International Health, Harvard
University
Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the final draft of the report
before its release. The review of this report was overseen by Dr. Melvin Worth.
Appointed by the Institute of Medicine, he was responsible for making certain
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Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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REVIEWERS

that an independent examination of this report was carried out in accordance with
institutional procedures and that all review comments were carefully considered.
Responsibility for the final content of this report rests entirely with the authoring
committee and the institution.

Copyright © National Academy of Sciences. All rights reserved.

Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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Preface

The Forum on Emerging Infections was created by the Institute of Medicine
(IOM) in 1996 in response to a request from the Centers for Disease Control and
Prevention (CDC) and the National Institutes of Health (NIH). The purpose of
the Forum is to provide structured opportunities for leaders from government,
academia, and industry to meet and examine issues of shared concern regarding
research, prevention, detection, and management of emerging or reemerging
infectious diseases. In pursuing this task, the Forum provides a venue to foster
the exchange of information and ideas, to identify areas in need of greater attention, to clarify policy issues by enhancing knowledge and identifying points of
agreement, and to inform decision makers about science and policy issues. The
Forum seeks to illuminate issues rather than resolve them; for this reason, it does
not provide advice or recommendations on any specific policy initiative pending
before any agency or organization. Its value derives instead from the diversity
of its membership and from the contributions that individual members make
throughout the activities of the Forum. In September 2003, the Forum changed
its name to the Forum on Microbial Threats.
ABOUT THE WORKSHOP
Long before the “germ theory” of disease was described, late in the nineteenth century, humans have known that climatic conditions influence the appear Pasteur, L. 1878. Germ theory and its applications to medicine and surgery. Read before the
French Academy of Sciences, April 29, 1878. Published in Comptes rendus de l’Academie des Sciences, lxxxvi, pp. 1037-1043. Taken from Scientific papers (physiology, medicine, surgery, geology).
New York: P. F. Collier and Son [c1910]. The Harvard classics v. 38. Modern History Sourcebook;
(accessed October 31, 2007).

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Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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xii

PREFACE

ance and spread of epidemic diseases. As was pointed out in the report Under
the Weather: Climate, Ecosystems, and Infectious Disease, “Since the dawn of
medical science, people have recognized connections between a change in the
weather and the appearance of epidemic disease. Roman aristocrats retreated to
hill resorts each summer to avoid malaria. South Asians learned early that, in high
summer, strongly curried foods were less likely to cause diarrhea.” 
Ancient notions about the effects of weather and climate on disease remain in
the medical and colloquial lexicon, in terms such as “cold” for rhinovirus infections; “malaria,” derived from the Latin for “bad air”; and the common complaint
of feeling “under the weather.” Today, the evidence is mounting that Earth’s
climate is changing, leading researchers to view the long-standing relationships
between climate and disease from a global perspective.
Variations in climate may affect the health of humans, animals, and plants
through direct impacts such as extreme heat or cold, or indirectly, by changing
environments—in ways that may, for example, alter the geographic distribution or transmission dynamics of infectious diseases. The most recent report of
the IPCC’s Working Group II, whose members studied the influence of climate
change on biological and social systems, stated with “very high confidence” that
“climate change currently contributes to the global burden of disease and premature deaths.” However, “at this early stage the effects are small but are projected
to progressively increase in all countries and regions.”
The warming of the Earth is already contributing to the worldwide burden
of disease and premature deaths, and is anticipated to influence the transmission
dynamics and geographic distribution of malaria, dengue, tick-borne diseases,
cholera, and other diarrheal diseases. In the specific case of the relationship

between climate and infectious diseases, it is important to recognize that a complex “web of causation” determines the distribution and transmission of infectious disease agents. In addition to climate, factors influencing the geographic
distribution and transmission of disease agents include: land-use patterns; a
variety of social, demographic, and geographical variables; trade and transportation; human and animal migration; and public health interventions. Some of these
factors are closely interrelated and influenced—directly or indirectly—by local,
regional, or global variations in climate.
 NRC

(National Research Council). 2001. Under the weather: climate, ecosystems, and infectious
disease. Washington, DC: National Academy Press.
 IPCC (Intergovernmental Panel on Climate Change). 2007a. Climate change 2007: the physical
science basis. Working Group I contribution to the Fourth Assessment Report of the IPCC. Cambridge, UK: Cambridge University Press.
 IPCC. 2007b. Climate change 2007: climate change impacts, adaptation, and vulnerability.
Contribution of Working Group II to the Fourth Assessment Report of the IPCC. Cambridge, UK:
Cambridge University Press.
 IPCC (2007b).
 NRC (2001).

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Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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xiii

PREFACE

The heating of the planet is also accelerating the hydrological cycle, increasing the likelihood of extreme weather events such as droughts, heavy precipitation, heat waves, hurricanes, typhoons, and cyclones. The projected health
impacts of climate change and extreme weather events are predominately negative, with the most severe impacts in low-income countries where the capacity to
adapt is weakest. Developed countries are also vulnerable to the health effects of
extreme temperatures, as was demonstrated in 2003 when tens of thousands of

Europeans died as a result of record-setting summer heat waves. Climate change
is expected to converge with, and intensify, additional contributors to infectious
disease emergence and reemergence including global trade and transportation,
land use, and human migration.
The Forum on Microbial Threats hosted a public workshop in Washington,
DC, on December 4 and 5, 2007, to consider the possible infectious disease
impacts of global climate change and extreme weather events on human, animal,
and plant health, as well as their implications for global and national security.
Through invited presentations and discussions, participants explored a range of
topics related to climate change and infectious diseases, including the ecological
and environmental contexts of climate and infectious diseases; direct and indirect
influences of extreme weather events and climate change on infectious diseases;
environmental trends and their influence on the emergence, reemergence, and
movement of vector- and non-vector-borne infectious diseases; opportunities and
challenges for the surveillance, prediction, and early detection of climate-related
outbreaks of infectious diseases; and the international policy implications of the
potentially far-reaching health impacts of climate change.
ACKNOWLEDGMENTS
The Forum on Microbial Threats and the IOM wish to express their warmest
appreciation to the individuals and organizations that gave their valuable time to
provide information and advice to the Forum through their participation in this
workshop. A full list of presenters can be found in Appendix A.
The Forum is indebted to the IOM staff who contributed during the course
of the workshop and the production of this workshop summary. On behalf of the
Forum, we gratefully acknowledge the efforts led by Eileen Choffnes, director
of the Forum, Kate Skoczdopole, senior program associate, and Sarah Bronko,
senior program assistant, for dedicating much effort and time to developing this
workshop’s agenda and for their thoughtful and insightful approach and skill
in planning for the workshop and translating the workshop’s proceedings and
 Kovats,

R. S., and A. Haines. 2005. Global climate change and health: recent findings and future
steps. Canadian Medical Association Journal 172(4):501-502.
 IOM (Institute of Medicine). 2003. Microbial threats to health: emergence, detection, and response. Washington, DC: The National Academies Press.

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Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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xiv

PREFACE

discussion into this workshop summary. We would also like to thank Dr. Assaf
Anyamba of the NASA Goddard Space Flight Center and the University of
Maryland Baltimore County for his invaluable contributions to this volume.
Special thanks to the following IOM staff and consultants for their valuable
contributions to this activity: Alison Mack, Bronwyn Schrecker, Lara Andersen,
and Florence Poillon.
Finally, the Forum wishes to recognize the sponsors that supported this activity. Financial support for this project was provided by the U.S. Department of
Health and Human Services: National Institutes of Health, National Institute of
Allergy and Infectious Diseases, Centers for Disease Control and Prevention, and
Food and Drug Administration; U.S. Department of Defense, Department of the
Army: Global Emerging Infections Surveillance and Response System, Medical
Research and Materiel Command, and Defense Threat Reduction Agency; U.S.
Department of Veterans Affairs; U.S. Department of Homeland Security; U.S.
Agency for International Development; Lawrence Livermore National Laboratory; American Society for Microbiology; Sanofi Pasteur; Burroughs Wellcome
Fund; Pfizer; GlaxoSmithKline; Infectious Diseases Society of America; and the
Merck Company Foundation. The views presented in this workshop summary

report are those of the workshop participants and rapporteurs and are not necessarily those of the Forum on Microbial Threats or its sponsors.
David A. Relman, Chair
Margaret A. Hamburg, Vice Chair
Forum on Microbial Threats

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Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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Contents

Summary and Assessment

1

1 Climate Change Challenges
54

Overview, 54

Climate Change, Extreme Events, and Human Health, 57
Andy Haines, M.B.B.S., M.D.

Climate Change and Human Health, 74
Paul R. Epstein, M.D., M.P.H.

Climate Change Futures: Health, Ecological, and Economic

Dimensions, 79

The Center for Health and the Global Environment, Harvard Medical
School

Impacts of Global Climate Change on Infectious Diseases, 90
Donald S. Burke, M.D.

References, 99
2 Climate, Ecology, and Infectious Disease
104

Overview, 104

The Marine Environment and Human Health: The Cholera Model, 109
Rita Colwell, Ph.D.
Extreme Weather and Epidemics: Rift Valley Fever and Chikungunya
Fever, 116
Jean-Paul Chretien, M.D., Ph.D.; Assaf Anyamba, Ph.D.; Jennifer
Small, M.A.; Compton J. Tucker, Ph.D.; Seth C. Britch, Ph.D.; and
Kenneth J. Linthicum, Ph.D.
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Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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xvi

CONTENTS

Plague and Climate, 128
Nils Chr. Stenseth, Dr.philos.

Climate Change and Plant Disease Risk, 143
Karen A. Garrett, Ph.D.
Climate Change and Infectious Disease: Impact on Human Populations in
the Arctic, 155
Alan J. Parkinson, Ph.D.

References, 168
3 Historical, Scientific, and Technological Approaches to
Studying the Climate-Disease Connection
179

Overview, 179
Drought, Epidemic Disease, and Massive Population Loss: 1,000 Years of
Record in Mexico, 183
Rodolfo Acuña-Soto, M.D., M.Sc., D.Sc.; David W. Stahle, Ph.D.;
Matthew D. Therrell, Ph.D.; and José Villanueva Diaz, Ph.D.

Wildlife Health as an Indicator of Climate Change, 192
Pablo M. Beldomenico, M.V., M.P.V.M., Ph.D.; Damien O. Joly, Ph.D.;
Marcela M. Uhart, M.V.; and William B. Karesh, D.V.M.
Use of Climate Variation in Vector-Borne Disease Decision Support
Systems, 198
William K. Reisen, Ph.D., and Christopher M. Barker, M.S.

References, 212
4 Policy Implications of the Health Effects of Climate

Change and Extreme Weather Events

Overview, 219

Influences of Migration and Population Mobility, 222
Douglas W. MacPherson, M.D., M.Sc. (CTM), F.R.C.P.C., and
Brian D. Gushulak, M.D.
Climate Change, Infectious Disease, and International Public Health
Policy, 230
Diarmid Campbell-Lendrum, D.Phil.

References, 238

219

Appendixes
A
B
C
D

Agenda
Acronyms
Glossary
Forum Member Biographies

Copyright © National Academy of Sciences. All rights reserved.

245
250

253
258


Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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Tables, Figures, and Boxes

Tables
SA-1Observed Changes in North American Extreme Events, Assessment of
Human Influence for the Observed Changes, and Likelihood That the
Changes Will Continue Through the Twenty-first Century, 7
SA-2Examples of Diseases Influenced by Environmental Conditions, 12
1-1Examples of Environmental Factors Known to Be Strongly Associated
with Certain Specific Infectious Diseases, 92
2-1Cholera Cases Officially Reported to WHO, 2004—Selected
Countries, 110
2-2Factors in Emergence and Spread of Rift Valley Fever and
Chikungunya Fever, 126
3-1
Famines in the Valley of Mexico, 185
3-2
Major Epidemics in the Valley of Mexico, 186
3-3
Deadliest Epidemics in Central Mexico, 187
3-4
Epidemics of Hemorrhagic Fevers in the Valley of Mexico, 190
3-5California Mosquito-Borne Virus Surveillance and Response Plan
Model Scores for Each Surveillance Parameter, 206
4-1Mobile Population Characteristics and Estimated Annual

Magnitudes, 223

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Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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TABLES, FIGURES, AND BOXES

Figures
SA-1 People affected by hydrometeorological disaster (millions per year), 8
SA-2 Potential health effects of climate variability and change, 11
SA-3 The epidemiological triad, 13
SA-4 The Convergence Model, 14
SA-5 Progression of bluetongue viruses emergence in Europe, 16
SA-6Hot spots of potential elevated risk for disease outbreaks under El
Niño conditions, 2006-2007, 17
SA-7(A) Using satellites to track Rift Valley fever; (B) January 2007
combined global Normalized Difference Vegetation Index (NDVI)
(depicted over land surfaces) and sea surface temperature (SST)
(depicted over oceans) anomaly mosaic, 19
SA-8 Interconnectedness of terrestrial, aquatic, and marine food webs, 25
SA-9 Ranavirus-associated disease in frogs, 26
SA-10Viral hemorrhagic septicemia (VHS) Rhabdoviridae
novirhabdovirus, 26
SA-11Chytridiomycosis (Batrachochytrium dendrobatidis) in Chiricahua

leopard frog (New Mexico), 27
SA-12Perkinsus—wood frog (Rana sylvatica) tadpole with massively
enlarged yellow liver, 27
SA-13The Arctic ice cap, September 2001 (Top) and September 2007
(Bottom), 29
SA-14 Arctic shipping shortcuts, 31
SA-15Global distribution of relative risk of an emerging infectious disease
(EID) event, 37
SA-16 Variation in Earth’s average surface temperature over the past 20,000
years, 44
SA-17 The Arctic is experiencing the fastest rate of warming as its reflective
covering of ice and snow shrinks, 45
SA-18 Observed changes in (A) global average surface temperature; (B)
global average sea level rise from tide gauge (blue) and satellite (red)
data; and (C) Northern Hemisphere snow cover for March-April, 46
SA-19 Drought is seizing more territory in the wake of mounting
temperatures, 47
1-1Observed changes in (A) global average surface temperature; (B)
global average sea level rise from tide gauge (blue) and satellite (red)
data; and (C) Northern Hemisphere snow cover for March-April, 59
1-2Multimodel averages and assessed ranges for surface warming
(compared to the 1980-1999 base period) for the SRES scenarios
A2 (red), A1B (green), and B1 (blue), shown as continuations of the
twentieth-century simulation, 60

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TABLES, FIGURES, AND BOXES

xix

1-3Pathways by which climate change may affect human health, including
infectious diseases, 63
1-4
ENSO teleconnections and risk map for malaria, 65
1-5Relative vulnerability of coastal deltas as indicated by estimates of the
population potentially displaced by current sea-level trends to 2050
(extreme >1 million; high 1 million to 50,000; medium 50,000 to
5,000), 68
1-6
Potential health effects of drought in developing countries, 68
1-7
Hurricane Katrina passing over the Gulf of Mexico, 75
1-8Increase from 1992 (left) to 2002 (right) in the amount of the
Greenland ice sheet melted in the summer, 78
1-9
Warm ocean waters fuel hurricanes, 81
1-10These data are taken from EMDAT (Emergency Events Database)
from 1975 to 2002, 84
1-11Transmission of influenza from infected guinea pigs to uninfected
exposed guinea pigs under different experimental conditions in which
ambient temperature and relative humidity were varied, 94
1-12Graph showing the amplitude of oscillations (y axis, peak-trough
ratio) as a function of the endogenous oscillation period (x axis) in a
stochastic forced S-I-R-S epidemic model for 2,000 sets of randomly
chosen parameters, 96
1-13Influenza virus types isolated in the United States between 1997 and

2007, 97
1-14Multiyear time series of incidence of dengue hemorrhagic fever cases
in Bangkok decomposed using the Empirical Mode Decomposition
method into three modes of different approximate frequencies, 98
2-1Bangladesh border, barrier islands, and location of Dacca, Matlab,
Mathbaria, and Bakerganj, 111
2-2Environmental parameters (top) and predicted versus actual cholera
incidence rate (bottom), 115
2-3
Global SST anomalies, September 2006, 119
2-4Seasonal rainfall anomalies in the Horn of Africa, SeptemberNovember 2006, 120
2-5NDVI anomalies (A) and RVF calculated risk (B) in the Horn of
Africa, December 2006, 121
2-6USAMRU-K mosquito collection sites (blue dots) and RVF risk
assessment, December 2006, 122
2-7Cumulative monthly rainfall (dotted line) and long-term mean
cumulative monthly rainfall (solid line) in Lamu and Mombasa, 124
2-8Outgoing longwave radiation (OLR) anomalies, July 2007, for the
Mediterranean region, 125

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TABLES, FIGURES, AND BOXES

2-9

The Convergence Model�����
, 127
2-10
The global distribution of plague, 129
2-11The global distribution of plague: (A) cumulative number of countries
that reported plague to WHO per continent, from 1954-1998; (B) the
temporal distribution of plague cases by continent, from 1954-1998,
also from WHO, 130
2-12Routes followed by the three plague pandemic waves (labeled 1, 2,
and 3), 131
2-13Possible transmission pathways for the plague bacterium, Yersinia
pestis, 133
2-14The field data used in Stenseth et al. (2006) were collected in a natural
plague focus in Kazakhstan, 135
2-15Relationship between the likelihood of detecting plague (solid line)
in gerbils and past burrow occupancy rates together with data on
presence or absence of plague at two sites, 137
2-16Tree-ring data suggesting that conditions during the Black Death and
the Third Pandemic were similar, 139
2-17
The modified trophic cascade model of Parmenter et al. (1999), 141
2-18Estimated potato late blight severity in the Altiplano area of Peru and
Bolivia based on weather measures during 2001-2004 used in a late
blight forecasting model, 147
2-19The plant disease triangle, illustrating the relationship between host,
pathogen, and environment necessary for disease to occur, 151
2-20
The circumpolar region showing administrative jurisdictions, 157
2-21The circumpolar region showing indigenous and nonindigenous
population distributions, 158

2-22The Arctic ice cap, September 2001 (Top) and September 2007
(Bottom), 159
2-23Proposed northwest and northeast shipping lanes through the Arctic
Ocean joining the Atlantic and Pacific Oceans, 160
3-1Sequence of surveillance data collected during seasonal virus
amplification, 182
3-2
West Nile virus transmission cycle, 199
3-3TOPS system brings ground and remote measures of climate into
ecological models to monitor and forecast risk, 201
3-4Incidence of human West Nile virus cases per million population and
temperature anomalies for the United States, 2003-2007, 203
3-5Sequence of surveillance data collected during seasonal virus
amplification, 205
3-6
Data flow through the Surveillance Gateway© system, 205
3-7
California mosquito district risk levels 1-5 for WNV transmission, 208

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TABLES, FIGURES, AND BOXES

3-8Intervention options for WNV shown in relation to (A) the
amplification curve and (B) the transmission cycle, 210

4-1������������������������������������������������������������������
Number of publications in PubMed referring to “health” and either
“climate ��������������������������������������������������
change” or “global warming” from 1990 to 2007, 234
Boxes
SA-1Under the Weather Key Findings: Linkages Between Climate and
Infectious Diseases, 4
SA-2 Emerging Infectious Diseases in the Aquatic-Marine Continuum, 26
SA-3Under the Weather Recommendations for Future Research and
Surveillance, 43
1-1
1-2
1-3
1-4

Regional-Scale Changes, 61
Key Points, 85
Vulnerabilities in the Energy Sector, 86
Case Studies in Brief, 88

4-1��������������������������������������������������������������������
The International Mandate for Stronger Action on Health and Climate
Change,����
235

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Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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Summary and Assessment

Global Climate Change and Extreme Weather Events:
Understanding the Contributions to
Infectious Disease Emergence
Humans have long recognized that climatic conditions influence the appearance and spread of epidemic diseases (NRC, 2001). Hippocrates’ observations
of seasonal illnesses, in the fifth century B.C.E., formed the basis for his treatise
on epidemics. Hippocratic medicine, which attempted to predict the course and
outcome of an illness according to its symptoms, also considered winds, waters,
and seasons as diagnostic factors. Ancient notions about the effects of weather
and climate on disease remain in the medical and colloquial lexicon, in terms
such as “cold” for rhinovirus infections; “malaria,” derived from the Latin for
“bad air”; and the common complaint of feeling “under the weather.”
Today, evidence that the Earth’s climate is changing (IPCC, 2007b) is leading
researchers to view the long-standing relationships between climate and disease
from a global perspective. Increased atmospheric and surface temperatures are
already contributing to the worldwide burden of disease and premature deaths,
and are anticipated to influence the transmission dynamics and geographic distribution of malaria, dengue fever, tick-borne diseases, and diarrheal diseases such
as cholera (IPCC, 2007a). Global warming is also accelerating the worldwide

The Forum’s role was limited to planning the workshop, and the workshop summary has been prepared by the workshop rapporteurs as a factual summary of what occurred at the workshop.



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Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence
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GLOBAL CLIMATE CHANGE AND EXTREME WEATHER EVENTS

hydrological cycle, increasing the intensity, frequency, and duration of droughts;
heavy precipitation events; and flooding (IPCC, 2007a). Such extreme weather
events have been increasing (IPCC, 2007a) and have been linked to global warming (Hoyos et al., 2006). These weather events may, in turn, contribute to and
increase the risk for a wide range of vector- and non-vector-borne diseases in
humans, plants, and animals (IPCC, 2007b).
The projected health consequences of future climate change and extreme
weather events are predominantly negative. The most severe impacts are expected
to occur in low-income countries where adaptive capacity is weakest. Developed
countries are also vulnerable to the health effects of weather extremes, as was
demonstrated in 2003 when tens of thousands of Europeans died as a result of
record-setting summer heat waves (Kovats and Haines, 2005). Climate change
is expected to reinforce additional contributors to infectious disease emergence
including global trade and transportation, land use, and human migration (IOM,
2003).
The Forum on Microbial Threats of the Institute of Medicine (IOM) held
a public workshop in Washington, DC, on December 4 and 5, 2007, to explore
the anticipated direct and indirect effects of global climate change and extreme
weather events on infectious diseases of humans, animals, and plants and the
implications of these health impacts for global and national security. Through
invited presentations and discussions, invited speakers considered a range of
topics related to climate change and infectious diseases, including the ecological
and environmental contexts of climate and infectious diseases; direct and indirect

influences of extreme weather events and climate change on infectious diseases;
environmental trends and their influence on the transmission and geographic
range of vector- and non-vector-borne infectious diseases; opportunities and
challenges for the surveillance, prediction, and early detection of climate-related
outbreaks of infectious diseases; and the international policy implications of the
potentially far-reaching impacts of climate change on infectious disease.
Organization of the Workshop Summary
This workshop summary report was prepared for the Forum membership in
the name of the rapporteurs and includes a collection of individually-authored
 In a personal communication on June 11, 2008, Diarmid Campbell-Lendrum (WHO) stated:
“Some benefits undoubtedly exist, for some populations. But I don’t know of any papers in the health
literature, WHO, or otherwise that specifically focus on reviewing the benefits separate from the
damages. These are usually referred to in reviews that look at the health effects overall. The health
chapter of the IPCC refers to both harms and benefits, and I think this would be the best citation, and
source for other studies. In IPCC (2007a), Confalonieri et al. note that the most important benefits
are likely to be reduced deaths in winter at high latitudes, increased food production in high latitudes
(for moderate climate change), and disruption of transmission cycles of some infectious disease in
some places (e.g., where it may become too hot or dry for malaria transmission in some locations).”

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