Heatwaves and Health: Guidance on Warning-System Development WMO-No. 1142 WORLD METEOROLOGICAL ORGANIZATION WORLD HEALTH ORGANIZATION Heatwaves and Health: Guidance on Warning-System Development G.R. McGregor, lead editor P. Bessemoulin, K. Ebi and B. Menne, editors WMO-No. 1142 WMO-No. 1142 © World Meteorological Organization and World Health Organization, 2015 The right of publication in print, electronic and any other form and in any language is reserved by WMO and WHO. Short extracts from WMO publications may be reproduced without authorization, provided that the complete source is clearly indicated. Editorial correspondence and requests to publish, reproduce or translate this publication in part or in whole should be addressed to: Chair, Publications Board World Meteorological Organization (WMO) 7 bis, avenue de la Paix Tel.: +41 (0) 22 730 84 03 P.O. Box 2300 Fax: +41 (0) 22 730 80 40 CH-1211 Geneva 2, Switzerland E-mail: [email protected] ISBN 978-92-63-11142-5 Cover illustration: AP photo/Rajesh Kumar Singh NOTE The designations employed in WMO publications and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of WMO and WHO concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or products does not imply that they are endorsed or recommended by WMO in preference to others of a similar nature which are not mentioned or advertised. The findings, interpretations and conclusions expressed in WMO publications with named authors are those of the authors alone and do not necessarily reflect those of WMO or its Members. CONTENTS Page CHAPTER AUTHORS ...................................................................................................................... v FOREWORD ................................................................................................................................... vii ACKNOWLEDGEMENTS ............................................................................................................. viii PREFACE.. ...................................................................................................................................... ix EXECUTIVE SUMMARY ................................................................................................................. xi CHAPTER 1: INTRODUCTION ........................................................................................................ 2 1.1 HEATWAVES: THEIR PHYSICAL CHARACTERISTICS ............................................................................. 2 1.2 SOCIETAL IMPACTS OF HEATWAVES ................................................................................................. 3 1.3 CLIMATE VARIABILITY, CLIMATE CHANGE, HEATWAVES AND ADAPTATION ............................................. 4 1.4 PURPOSE OF THE GUIDANCE .......................................................................................................... 4 CHAPTER 2: HEAT AND HEALTH ................................................................................................. 5 2.1 INTRODUCTION .............................................................................................................................. 5 2.1.1 Human physiology and heat ........................................................................................................ 5 2.1.2 Acclimatization ............................................................................................................................ 6 2.2 HEAT, ILLNESS AND DEATH ............................................................................................................. 6 2.3 OBSERVED IMPACTS OF HEATWAVES ON HEALTH .............................................................................. 8 2.3.1 Mortality ...................................................................................................................................... 8 2.3.2 Morbidity ..................................................................................................................................... 9 2.4 FACTORS THAT INCREASE THE RISK OF HEAT-RELATED ILLNESS AND DEATH ........................................ 9 2.4.1 Adaptation ................................................................................................................................. 10 2.4.2 Socioeconomic factors .............................................................................................................. 10 2.4.3 Physiological factors and age ................................................................................................... 10 2.4.4 Medical conditions .................................................................................................................... 11 2.4.5 Gender ...................................................................................................................................... 11 2.4.6 Medication ................................................................................................................................ 12 2.4.7 Behaviour .................................................................................................................................. 12 2.5 SUMMARY ................................................................................................................................... 13 CHAPTER 3: ASSESSMENT OF HEAT STRESS ........................................................................ 14 3.1 HEATWAVES ................................................................................................................................ 14 3.2 EXPOSURE .................................................................................................................................. 15 3.3 THERMAL ASSESSMENT PROCEDURES ........................................................................................... 16 3.3.1 Simplified biometeorological indices ......................................................................................... 17 3.3.2 Heat-budget models .................................................................................................................. 19 3.3.3 Holistic approaches ................................................................................................................... 22 3.3.4 Adaptation considerations ......................................................................................................... 22 3.4 SUMMARY ................................................................................................................................... 24 CHAPTER 4: HEAT–HEALTH WARNING SYSTEMS: DEFINITION AND METHODOLOGY ..... 25 4.1 WHAT IS A HEAT–HEALTH WARNING SYSTEM? .............................................................................. 25 4.2 THE FRAMEWORK FOR DEVELOPMENT ........................................................................................... 26 4.3 METRICS OF HEAT-EVENT DETERMINATION IN HEAT-HEALTH WARNING SYSTEMS ............................... 27 4.3.1 Single- or few-parameter methods ............................................................................................ 27 4.3.2 Heat budget .............................................................................................................................. 30 4.3.3 Synoptic-based systems ........................................................................................................... 30 4.3.4 Other methodologies ................................................................................................................. 31 4.4 HOW WARNING THRESHOLDS ARE DETERMINED .............................................................................. 31 4.4.1 Determining thresholds ............................................................................................................. 31 4.4.2 Defining and determining different levels of warnings ............................................................... 32 4.4.3 Other considerations with warnings .......................................................................................... 33 4.5 ISSUANCE OF WARNINGS .............................................................................................................. 34 4.6 THE FUTURE OF PRESENT-DAY HEAT–HEALTH WARNING SYSTEMS ................................................. 36 4.7 SUMMARY ................................................................................................................................... 38 iv HEATWAVES AND HEALTH: GUIDANCE ON WARNING-SYSTEM DEVELOPMENT Page CHAPTER 5: COMMUNICATING HEAT–HEALTH WARNINGS AND HEAT-RELATED INFORMATION TO STAKEHOLDERS AND THE PUBLIC ........................................ 39 5.1 ELEMENTS OF WARNINGS ............................................................................................................. 39 5.1.1 The need to warn ...................................................................................................................... 39 5.1.2 The decision to warn ................................................................................................................ 40 5.1.3 Content of a warning ................................................................................................................. 40 5.1.4 Language 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