OIT - Climate-Related Heat Stress and Occupational Mortality in Colombia

X Climate-Related Heat Stress and Occupational Mortality in Colombia Authors / Sévane Ananian, Sergei Suarez Dillon Soares, Tahmina Karimova

August / 2026 ILO Working Paper 178© International Labour Organization 2026 Attribution 4.0 International (CC BY 4.0) This work is licensed under the Creative Commons Attribution 4.0 International. See: https:// creativecommons.org/licenses/by/4.0/. The user is allowed to reuse, share (copy and redistribute), adapt (remix, transform and build upon the original work) as detailed in the licence. The user must clearly credit the ILO as the source of the material and indicate if changes were made to the original content. Use of the emblem, name and logo of the ILO is not permitted in connection with translations, adaptations or other derivative works. Attribution – The user must indicate if changes were made and must cite the work as follows: Ananian, S., Suarez Dillon Soares, S., Karimova, T. Climate-Related Heat Stress and Occupational Mortality in Colombia. ILO Working Paper 178. Geneva: International Labour Office, 2026.© ILO. Translations – In case of a translation of this work, the following disclaimer must be added along with the attribution: This is a translation of a copyrighted work of the International Labour Organization (ILO). This translation has not been prepared, reviewed or endorsed by the ILO and should not be considered an official ILO translation. The ILO disclaims all responsibility for its content and accuracy. Responsibility rests solely with the author(s) of the translation. Adaptations – In case of an adaptation of this work, the following disclaimer must be added along with the attribution: This is an adaptation of a copyrighted work of the International Labour Organization (ILO). This adaptation has not been prepared, reviewed or endorsed by the ILO and should

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ISBN 9789220436516 (print), ISBN 9789220436523 (web PDF), ISBN 9789220436530 (epub), ISBN 9789220436547 (html). ISSN 2708-3438 (print), ISSN 2708-3446 (digital) Also available in: Spanish ISBN 9789220436554 (print); 9789220436561 (web PDF); 9789220436578 (epub); 9789220436585 (html); ISSN 2708-4248 (print), ISSN 2708-4256 (digital); DOI https://doi.org/10.54394/00034732 https://doi.org/10.54394/00034736The designations employed in ILO publications, which are in conformity with United Nations practice, and the presentation of material therein do not imply the expression of any opinion whatsoever on the part of the ILO concerning the legal status of any country, area or territory or of its authorities, or concerning the delimitation of its frontiers or boundaries. See: www.ilo. org/disclaimer. The opinions and views expressed in this publication are those of the author(s) and do not necwhatsoever on the part of the ILO concerning the legal status of any country, area or territory or of its authorities, or concerning the delimitation of its frontiers or boundaries. See: www.ilo. org/disclaimer. The opinions and views expressed in this publication are those of the author(s) and do not necessarily reflect the opinions, views or policies of the ILO. Reference to names of firms and commercial products and processes does not imply their endorsement by the ILO, and any failure to mention a particular firm, commercial product or process is not a sign of disapproval. Information on ILO publications and digital products can be found at: www.ilo.org/researchand-publications ILO Working Papers summarize the results of ILO research in progress, and seek to stimulate discussion of a range of issues related to the world of work. Comments on this ILO Working Paper are welcome and can be sent to research@ilo.org.

Authorization for publication: Caroline Fredrickson, Director, Research Department ILO Working Papers can be found at: www.ilo.org/research-and-publications/working-papers Suggested citation: Ananian, S., Suarez Dillon Soares, S., Karimova, T. 2026. Climate-Related Heat Stress and Occupational Mortality in Colombia , ILO Working Paper 178 (Geneva, ILO). https://doi.

org/10.54394/0003473601 ILO Working Paper 178 Abstract Using death certificate data recorded in the Colombian vital statistics system for 2017–2021, together with temperature data from meteorological stations, this study examines mortality associated with air temperatures above 26°C across occupations classified at the 2-digit level of the International Standard Classification of Occupations (ISCO-08). The findings highlight that agricultural workers, assemblers, and health and teaching professionals face the highest mortality risk associated with exposure to high temperature in Colombia. Overall, male workers are more affected by the consequences of high temperatures. However, women appear to be particularly vulnerable in occupations such as health associate professionals, where they account for a large

cultural workers, assemblers, and health and teaching professionals face the highest mortality risk associated with exposure to high temperature in Colombia. Overall, male workers are more affected by the consequences of high temperatures. However, women appear to be particularly vulnerable in occupations such as health associate professionals, where they account for a large majority of workers. Preventive measures, including risk assessment, should therefore be reinforced, especially for these occupations in the context of global climate warming. Regarding remediation, the coverage of common health insurance has expanded significantly in recent decades and now reaches almost 99 per cent of the entire population, but only around half of the working population is covered by social protection schemes for occupational risks. About the authors Sévane Ananian joined the Research Department of the International Labour Organization (ILO) in September 2021 as a Senior Economist. His research focuses on wages, working conditions, and inequalities. Prior to joining the Research Department, he served as a Wage and Social Dialogue Specialist at the ILO Office in Cairo. Before joining the ILO, he worked in the statistical services of the French Ministries of Labour and Health, where he also served as rapporteur to the French Minimum Wage Expert Group. Sergei Suarez Dillon Soares has worked at the Institute for Applied Economic Studies (Ipea) in Brasília since 1998 and has been at the IPC-IG since 2015. His work has been on inequality, poverty, education, racial discrimination, social protection, and the labour market. He has been at the ILO since 2020 and is now in the Research Department. Tahmina Karimova is a lawyer specialised in public international law, sustainable development, international labour standards, human rights law, and arms control. She is a Law Research Specialist at the RESEARCH Department, ILO. Previously, she has worked as a Human Rights Officer in the Office of the High Commissioner for Human Rights, and prior to that as a Research Fellow at the Geneva Academy of the International Humanitarian Law and Human Rights/Law Faculty of the University of Geneva. She holds an LL.M from the University of Essex and a PhD

Officer in the Office of the High Commissioner for Human Rights, and prior to that as a Research Fellow at the Geneva Academy of the International Humanitarian Law and Human Rights/Law Faculty of the University of Geneva. She holds an LL.M from the University of Essex and a PhD in International Law from the University of Geneva and the Graduate Institute of International and Development Studies.02 ILO Working Paper 178 Abstract 01 About the authors 01 X Introduction 05 X 1 Background on the exposure of Colombian workers to extreme temperatures 08 X 2 Data and methodology 09 Vital statistics 09 Temperature data 10 Gran Encuesta Integrada de Hogares (GEIH) 12 Econometric model 12 X 3 Results 15 Agricultural workers, assemblers, and health and teaching professionals are among the occupations most affected by the deadly consequences of elevated temperatures 15 Overall, men are at greater risk than women when it comes to the fatal consequences of high temperatures 18 X 4 Possible policies to tackle the effects of elevated temperatures on Colombian workers 21 X Conclusion 25

Annex I: Complementary statistics 26

Annex II: Results from a Poisson regression model 35

References 36 Acknowledgements 40 Table of contents03 ILO Working Paper 178 List of Figures Figure 1: Distribution of the Colombian population by department 11 Figure 2: Distribution of the IDEAM meteorological stations 11 Figure A1: Distribution of employed individuals across broad occupational categories by year (percentage) 26 Figure A2: Kernel density of monthly deaths by monthly maximum temperature (average for 2017–2021) 29 Figure A3: Number of months per year with maximum temperature between 26°C and 32°C and above 32°C, and with minimum temperatures below 7°C, and between 7°C and 20°C (average per municipality, 2017–2021) 3004 ILO Working Paper 178 List of Tables

and above 32°C, and with minimum temperatures below 7°C, and between 7°C and 20°C (average per municipality, 2017–2021) 3004 ILO Working Paper 178 List of Tables Table 1: Number of deaths per 1,000 workers associated with temperature between 26°C and 32°C and above 32°C 16 Table 2: Number of deaths per 1,000 male and female workers associated with temperature between 26°C and 32°C and above 32°C 19 Table A1: Distributions of deaths across occupations for the whole country and in the sample studied (percentage) 27 Table A2: Distribution of workers across occupations according to the ISCO-08 classification (percentage) 31 Table A3: Number of deaths per 1,000 workers associated with temperature below 7°C, between 7°C and 20°C, between 26°C and 32°C and above 32°C 33 Table A4: Multiplicative increase in the number of deaths in each occupation associated with temperature below 7°C, between 7°C and 20°C, between 26°C and 32°C and above 32°C (results from a Poisson regression) 3505 ILO Working Paper 178 X Introduction Without adequate mitigation efforts, temperatures are expected to increase with human-induced climate change, making heat stress and heat waves more common (IPCC 2023). In this context, workers will increasingly be exposed to excessive heat, which constitutes an occupational health danger– with high body temperature or dehydration potentially causing heat exhaustion, heat stroke, and, in extreme cases, death (ILO 2022a; UNDP et al. 2016; ILO 2024a). Also, by slowing down the body and increasing the necessity of breaks, heat stress reduces the productivity of workers, with a decrease estimated at 2.2 per cent by 2030 (ILO 2019). A decrease in productivity affects the activity of businesses and for the worse-affected countries, this could also have an impact on their development path.

workers, with a decrease estimated at 2.2 per cent by 2030 (ILO 2019). A decrease in productivity affects the activity of businesses and for the worse-affected countries, this could also have an impact on their development path. While the existing scientific literature highlights the impact of elevated temperatures and investigates the consequences of extreme heat in terms of morbidity and mortality for the general population, relatively few analyses have looked at these dimensions for the population of workers specifically. Yet it is known that certain categories of workers are at greater risk of heat stress and that actors in the world of work have a role to play in the design of both preventive measures against heat stress in the workplace and measures aiming at mitigating the rise of temperatures (ILO 2019). With regard to mortality in the general population, a statistical study conducted across 13 countries (Australia, Brazil, Canada, China, Italy, Japan, South Korea, Spain, Sweden, Taiwan, Thailand, the United Kingdom and the United States of America) has for instance shown that extreme temperature (hot and cold) are responsible for 0.86 per cent of total mortality, with more deaths attributable to cold than to heat (Gasparrini et al. 2015). More recently, a meta-analysis on various cardiovascular health outcomes has highlighted that a 1°C temperature rise is associated with an increase in the risk of cardiovascular-related morbidity by 2.1 per cent, and an increase in morbidity due to arrhythmias, cardiac arrest and coronary heart disease (Liu et al. 2022). Elevated risks of morbidity and mortality linked to heat exposure are found for women, people 65 or older, and individuals living in tropical climates. Specifically in Colombia, evidence shows an increase in mortality linked to elevated temperature. An additional day with a mean temperature above 27°C leads to about 0.24 deaths per 100,000, or 0.7 per cent of the monthly death rate (Helo Sarmiento 2023). Recently, the International Labour Organization (ILO) has calculated global estimates of the

a mean temperature above 27°C leads to about 0.24 deaths per 100,000, or 0.7 per cent of the monthly death rate (Helo Sarmiento 2023). Recently, the International Labour Organization (ILO) has calculated global estimates of the work-related health impact of heat, using global climate models and assumptions on the impact of increased temperatures on occupational injuries based on data from the existing literature. Using this framework, the study calculates that 22.85 million occupational injuries and 18,970 deaths per year are directly related to exposure to excessive heat at work (ILO 2024a). However, to design responsive policies, the global estimates must be complemented by more granular data at the country and occupational levels. Furthermore, beyond model-based predictions, empirical analyses through observational data on mortality across occupations are necessary to confirm the predictions and assess the impacts in specific contexts. Quantitative empirical studies that have aimed at measuring the impact of elevated temperatures on workers in terms of health consequences have mainly focused on specific occupations, often in developed countries where data collection may be more systematic. A 2014 review of the literature on heat exposure in the workplace, which included 55 studies from 1997 to 2012, found that 20 per cent of the articles focused on manufacturing workers in the steel and foundry industries, 18 per cent on miners, 16 per cent on mixed manual workers, 13 per cent on construction workers, 13 per cent on farmers, and 5 per cent on the armed forces (Xiang et al. 2014).06 ILO Working Paper 178 The results highlight in particular that manual workers exposed to extreme heat or in hot environments may be at risk of heat stress. The article also points to imbalances between the data available for developed and developing countries. Beyond specific occupational categories, some studies have focused on the characteristics of the work performed, including working conditions and the work environment. For example, a more recent attempt to study the relationship between health and heat exposure on Californian data suggests that outdoor work affects heat-related morbidity at the community level (Riley et al. 2018).

studies have focused on the characteristics of the work performed, including working conditions and the work environment. For example, a more recent attempt to study the relationship between health and heat exposure on Californian data suggests that outdoor work affects heat-related morbidity at the community level (Riley et al. 2018). With regard to mortality specifically, a relatively limited number of studies have sought to analyse the impact of elevated temperature on the number of deaths in each occupation. In particular, using an industry sector approach, an analysis conducted on data from 2000-2010 in the United States found higher rates of heat-related deaths in the agriculture and construction industries (Gubernot et al. 2015). In more recent research developments, a study on Nepalese migrant workers in the construction trade in Qatar has pointed to an increased cardiovascular mortality during hot periods most likely due to severe heat stress (Pradhan et al. 2019). Surveys on Korean workers covering 2002 to 2015 have also shown that the maximum daily temperature was associated with the risk of death and outdoor mortality (Yoon et al. 2021). Hence, existing observational literature on heat-related mortality and morbidity in the world of work has focused primarily on specific occupations or on limited geographical areas, often within high-income countries. Comprehensive empirical studies measuring the risk of heat-related health effects across various occupations are rare, especially regarding mortality. In Colombia, such an analysis however is warranted by virtue of the framework set out in the National Adaptation Plan (NAP) on Climate Change, particularly its Objective 1, which seeks greater knowledge about potential risks and current impacts of climate change, including their economic valuation and effect on people and ecosystems (Colombia 2016). This objective is also consistent with the principles of a just transition as articulated in the ILO Guidelines for a just transition towards environmentally sustainable economies and societies for all, which call for integrating business and labour considerations — including occupational safety and health, and resilience to the impacts of climate change — into adaptation and mitigation frameworks (ILO 2015). Improving the evidence base on workers' vulnerability to heat stress

Guidelines for a just transition towards environmentally sustainable economies and societies for all, which call for integrating business and labour considerations — including occupational safety and health, and resilience to the impacts of climate change — into adaptation and mitigation frameworks (ILO 2015). Improving the evidence base on workers' vulnerability to heat stress could inform climate-sensitive sectors and occupations, as well as worker-centred adaptation measures, supporting Colombia’s implementation of national schemes such as the NAP and the Nationally Determined Contribution (NDC)1. The present paper will aim at providing empirical evidence of the relationship between workers’ mortality and air temperature in Colombia. This analysis could have several practical applications. In particular, it will highlight occupations that are most exposed to the dreadful health consequences of elevated air temperatures and can therefore assist labour administration, the occupational safety and health (OSH) system and social partners in identifying the most vulnerable workers. The analysis also takes into account cold temperatures levels and deaths related to cold over the period of observation. However, the study focuses on hot temperatures, as their prevalence is likely to increase substantially in the context of climate change and global warming. The paper is divided according to the following outline. The first section will describe the data and methodology used to estimate the impact of elevated temperature on Colombian mortality 1 This is the official and legally binding commitment the country has made under the Paris Agreement to address climate change.07 ILO Working Paper 178 per occupation. The second section will delve into the analysis of the estimates, while the third will offer some concluding remarks.08 ILO Working Paper 178 X 1 Background on the exposure of Colombian workers to extreme temperatures

Colombia's climate ranges from tropical conditions in the coastal and eastern lowland regions to cooler conditions in the highlands and the Andes. The country can be broadly divided into three climatic zones: the tropical lowlands, below 1,000 metres above sea level, are characterized by high temperatures throughout the year; the temperate zone, between 1,000 and 2,000 metres,

cooler conditions in the highlands and the Andes. The country can be broadly divided into three climatic zones: the tropical lowlands, below 1,000 metres above sea level, are characterized by high temperatures throughout the year; the temperate zone, between 1,000 and 2,000 metres, has milder temperatures; and the cold highland zone, above 2,000 metres, with mean annual temperatures ranging between 13°C and 17°C. Precipitation patterns vary considerably across regions, with two rainy seasons in much of the Andean region and one in the Caribbean region (UNEP/GRID-Geneva, n.d.). In addition to climate-related dimensions, other factors linked to the environment may impact the exposure of Colombian workers to extreme temperatures. These include for instance factors related to urbanisation and the presence of heat islands. Urban heat island refers to the relative warmth of a city in comparison with rural areas, which may result from several factors, such as reduced ventilation and heat trapping stemming from the close proximity of tall buildings, heat generated from human activities, heat-related properties of concrete or limited vegetation (Doblas-Reyes et al. 2023). In this regard, it has been highlighted that Colombia has undergone a fast and rapid urbanisation process, with the share of the population living in urban areas almost doubling between 1950 and 2018 (OECD 2022). In a context of global warming, this trend is likely to have exacerbated the increase in the temperatures experienced by the Colombian population. Furthermore, work-related factors are also likely to influence and compound the effects that elevated temperatures may have on workers. In addition to the metabolic heat generated by the physical intensity of work, other elements related to the working conditions can shape the exposure to heat stress. These include excessive heat resulting for instance from limited air flow at the workplace, and thermal insulation linked to clothing and personal protective equipment (ILO 2024b). Such factors are partly determined by existing regulatory guidelines, which may include for instance regulations concerning the rest breaks in cases of extreme heat as adopted

posure to heat stress. These include excessive heat resulting for instance from limited air flow at the workplace, and thermal insulation linked to clothing and personal protective equipment (ILO 2024b). Such factors are partly determined by existing regulatory guidelines, which may include for instance regulations concerning the rest breaks in cases of extreme heat as adopted in certain countries (see section 2.4 below). But as Colombia has a high level of informality – estimated at 56 per cent by the ILO in 20242 –, a relatively large share of the working population might not be optimally covered by occupational safety and health systems and measures aiming at reducing the impact of heat stress on health. The potential impact of heat stress on workers in Colombia has already been highlighted by the ILO in its evaluation of the effect of heat on productivity and working hours. According to ILO (2019), Colombia appeared to be among the three South American countries with the highest productivity losses due to heat stress in 1995 (0.55 per cent), together with Guyana (1.56 per cent) and Suriname (0.64 per cent). This calls for further investigation of the impact of elevated temperature on workers, including on outcomes such as workers’ mortality and morbidity, to complement previous results related to the effect on working hours. 2 ILOSTAT Indicator Catalog (accessed on 30/07/2025).09 ILO Working Paper 178 X 2 Data and methodology

The methodology is based on a comparison of monthly mortality data by occupations with monthly recorded maximum and minimum air temperatures at the local level. Since both air temperature and mortality are recorded at local levels across several years, geographical and time variations in the data allow the effects to be identified. For this purpose, the Colombian vital statistics are compared with the temperature data from the Colombian Institute of Hydrology, Meteorology and Environmental Studies (IDEAM). Vital statistics Colombian vital statistics microdata was retrieved from the National Administrative Department of Statistics (DANE) in order to get the information on each registered death for years 2017–20213.

compared with the temperature data from the Colombian Institute of Hydrology, Meteorology and Environmental Studies (IDEAM). Vital statistics Colombian vital statistics microdata was retrieved from the National Administrative Department of Statistics (DANE) in order to get the information on each registered death for years 2017–20213. These data include the date of each death that occurred during the considered years, and a set of variables describing characteristics of the deceased person. These latter include information such as the age category of the deceased person (e.g., variable GRU_ED1), their gender (variable SEXO) and occupation (variable OCUPACION), as well as codes defining the geographical area (“departamento”) and municipality (“municipio”) where the death occurred (variables COD_DPTO and COD_MUNIC). The variable OCUPACION provides a short plain language description of the occupation of each deceased individual but not directly the code of the occupation according to the International Standard Classification of Occupations (ISCO). Furthermore, the text of the provided descriptions sometimes slightly differs for individuals with the same occupation. In this context, in order to build a consistent codification for the occupation of each individual in the database, a correspondence table between the OCUPACION variable and the 2-digit ISCO-08 code was built manually, partly with the assistance of “fuzzy matching” techniques and large language models to find common elements of language between the two classifications of occupations.4 This step was key to be able to provide statistics on the impact of heat stress on broad occupational categories, which is the subject of Section 3 of the paper.5 Finally, using these various pieces of information, it was possible to calculate the number of deaths in each Colombian municipality, for each occupation at the 2-digit ISCO-08 level and each month of the period 2017– 2021.6 In order to focus on the population that is most likely to participate in the labour force, deaths of persons under 15 years old and over 60 years old are not taken into account, as well as those of persons whose occupation is missing or reported as “household” or

of the period 2017– 2021.6 In order to focus on the population that is most likely to participate in the labour force, deaths of persons under 15 years old and over 60 years old are not taken into account, as well as those of persons whose occupation is missing or reported as “household” or “retired” in the database.7 These calculations were also made separately for men and women, to be able to see if the effect of high temperatures on mortality differed according to gender. 3 These are continuous statistics that collect data on births, fetal and non-fetal deaths, providing information that reveals changes in mortality and fertility rates and patterns, and offering a dynamic view of the population. 4 “Fuzzy matching” techniques (or “approximate string matching”) allow researchers to find approximate matches to a specific string of characters. 5 The correspondence table between the OCUPACION variable and the ISCO-08 classification is available upon request. 6 The municipalities ("municipios") refer to an administrative subdivision of Colombia. Grouping of municipalities form departments (32 departments in total in Colombia). 7 Referred to as « HOGAR » and « PENSIONADO » in the original database.10 ILO Working Paper 178 Temperature data For the purpose of the analysis, the detailed daily dry-air temperature data were provided by the IDEAM and measured across 648 meteorological stations distributed in the country. For each municipality covered by this network, the data were aggregated to obtain for each month of the 2017–2021 period the minimum and the maximum of the daily temperatures.8 For data availability reasons, dry air temperatures were used instead of alternative indices that may reflect more comprehensively the environmental conditions, such as Wet Bulb Globe Temperatures (WBGT)9 The use of WBGT would have reduced substantially the geographical coverage of the temperature data, since not all meteorological stations can provide the necessary information to estimate it even though adding humidity would have allowed more fine-tuning of estimates because the Colombian climate is diverse and includes tropical and humid areas. In each municipality with a meteorological station, the minimum and maximum monthly temture data, since not all meteorological stations can provide the necessary information to estimate it even though adding humidity would have allowed more fine-tuning of estimates because the Colombian climate is diverse and includes tropical and humid areas. In each municipality with a meteorol