Climate Change & Health
To coincide with global climate change summit – the 16th session of the Conference of the Parties to the UNFCCC (COP 16) – in Cancun, Mexico in early December, the international peer reviewed journal Global Health Action published a thematic series of papers focusing on a hitherto unrecognised consequence of climate change – impacts upon working people due to heat exposure and non-heat related risks.
Global Health Action is an open-access journal and the series of papers is available online.
Professor Kjellstrom, one of the Guest Editors for the series explains: “The impact of increasing heat exposure on millions of working people, particularly in low and middle income countries, has been a ‘forgotten effect' of climate change.” He further stresses the need to carry out research that “quantifies the impacts of heat on the health and work capacity of people in a variety of occupations as these impacts may undermine economic development and the efforts to achieve the Millennium Development Goals.”
The researchers behind this series of articles report that billions of people – particularly agricultural workers in lowand middle income countries – are already exposed to health risks associated with occupational heat exposures and heat stress. In addition to the direct effects of heat, such workers are also more at risk of non-heat related problems such as exposure to various infectious diseases, extreme weather events, stress and mental health issues, and malnutrition. Charmian M. Bennett and Anthony J. McMichael of the National Centre for Epidemiology and Population Health at the Australian National University point out, for example, that “most microbial pathogens are sensitive to climatic conditions. Climate thus determines where and when a particular infectious disease could occur. Outdoor workers are especially at risk of vector-borne disease and, as the global climate changes, they may be exposed to vector-borne diseases in areas and at times where transmission was previously not possible.” Workers may also be placed at risk as they move working hours to cooler periods of the day, which also coincide with times when insects carrying disease are more active.
Workers’ possibilities for protecting themselves, and a lack of systematic measures by management to protect them, look to be common. The sugar cane workers that Jennifer Crowe and her colleagues at the Regional Institute for Studies on Toxic Substances at the National University of Costa Rica investigate are all too familiar with this description. Although they start their workday during the early morning hours to take advantage of cooler temperatures, these workers toil under heat and humidity during most of the work day with few efforts being made to accommodate their situation. Angela Mathee, the African Medical Research Council, Johannesburg, South Africa and School of Public Health, at the University of the Witwatersrand, found similar results when investigating agricultural and construction workers in South Africa. Mathee shows that “where daily maximum temperatures may reach +40oC workers reported a wide range of heat-related effects, including sunburn, sleeplessness, irritability and exhaustion leading to difficulty in maintaining work levels and output during very hot weather. Few if any measures were being undertaken by employers to protect health or improve worker comfort.” In Thailand workers face similar risks. Uma Langkulsen and colleagues at the Faculty of Public Health, Thammasat University, report that at four of the five worksites they investigated in Thailand, workers faced extreme conditions – and at one site dangerous conditions – in which heat cramp and exhaustion may be possible and sunstroke and heat exhaustion are likely and prolonged exposure may lead to heatstroke. Nonetheless, precautions to protect health rested with the workers themselves.
One reason for the lack of measures to support workers might be related to different perceptions of heat stress between management and front line workers. Researchers from the Department of Environmental Health Engineering, at Sri Ramachandra University in India found precisely this in the case studies they conducted at 10 different industrial units in a city in Southern India. Researcher Kalpana Balakrishnan states that “there was a noticeable disconnect between worker’s perceptions and their ability to secure workplace improvements related to heat stress from the management. Given the potential implications of future climate change related increases in ambient heat stress that are likely to translate into workplace exposures in developing country settings, concerted efforts are needed to integrate exposure assessments with assessments of productivity as well as health impacts.”
The next generation of workers is already beginning to suffer according to Léonie Dapi, Department of Epidemiology and Global Health at Umeå University. A study she and her colleagues from several countries conducted with school children in Cameroon revealed a significant correlation between daily indoor temperature and the percentages of schoolchildren who felt very hot, had fatigue and headache.
The situation is expected to grow worse. The fourth assessment report from the Inter-governmental Panel on Climate Change determined in 2007 that the global average surface temperature increased by about 0.74oC over the last 100 years with greater changes in extreme temperatures and weather occurring during the past 50 years. As the planet continues to heat up, workers in a growing number of regions around the world will experience high risk to extreme high risk conditions, as Olivia Hyatt and her colleagues demonstrate through a modelling tool that allows us to glimpse future scenarios. Australia, India and the Southern United States and Central America can experience high and – in some areas – extreme risks in the future.
As with other areas of climate change, these impacts are unevenly distributed between low- and middle income countries and the richer nations of the world. There is also an important gender perspective to be taken into account with respect to female biology as well as social divisions of labour and other complex factors. However, as researchers Preet, Nilsson, Schumann and Evengård of Umeå University report, a review of the literature in the field of climate change and health reveals that such a gender perspective is non-existent.
Impacts upon workers translate into both public health and economic issues that need to be addressed at multiple levels: family, community, employer, region and country. Guest Editors Tord Kjellstrom and Maria Nilsson argue that “preventive policies, oriented to both mitigation and adaptation will need to be strengthened or initiated Particularly vulnerable sectors and populations need to be identified and protected from future adverse effects.”
Dr Nilsson states: “Just imagining more use of air conditioning as a solution to the current and future heat problems is not enough as many jobs are carried out in places where air conditioning cannot be applied. In addition, air conditioning contributes to the greenhouse emissions and future climate change. Policies encouraging other means to create cooler work environments are needed, including building design that creates ‘natural cooling’ and urban design that takes advantage of shading trees, water features, etc. to reduce the local ‘heat island effect’.”
The WHO is an important actor in providing guidelines and support programmes in this area. Dr Nilsson and Kjellstrom recommend that in addition to the adoption of a Global Plan of Action on Workers’ Health, more should be done to highlight occupational health as a part of the protection of people from direct health hazards due to climate change. They call upon organisations like the International Labour Organization, the World Meteorological Organization and the International Organization for Standardization to act as partners in developing policies to combat and prevent the effects of climate change for workers.
What is also needed, according the researchers, is more research. Dilia Rizpah Hollowell, an anthropologist with the Institute for Global health at the University College of London, reveals that much of what we know today about the effects of heat on workers can be derived from military concerns about effects on soldiers, going back to the 1800s. Over time, she argues, there has been a shift from an identification of common symptoms behind heat stroke, to understanding the physiological processes behind the pathogenesis of heat stroke. Only recently has research been conducted to investigate techniques for mitigating effects, such as specially designed clothing.
Hollowell’s work, and that of several other authors in this series, is part of a larger research programme known as the high occupational temperature health and productivity suppression (HOTHAPS) programme. According to the group’s Principal Investigator Tord Kjellstrom, HOTHAPS is a multi-centre health research and prevention programme aimed at characterising and quantifying the extent to which working people are affected by, or adapt to, heat exposure while working. In addition to empirical research, the programme also involves developing new tools and methods for calculating such things as heat stress, exemplified by a contribution from Ingvar Holmér, of the Thermal Environment Laboratory, Faculty of Engineering at Lund University, Sweden, who also points out that, “In order to assess and evaluate conditions, heat stress must be described correctly and measured according to internationally recognised methods”.
Given the lack of research in this area, particularly the lack of research on workers outside the military, “climate change impacts on working people” makes an important contribution to the climate change discourse.
Global Health Action is an international peer-reviewed Open Access journal affiliated with the Umeå Centre for Global Health Research (UCGHR) at Umeå University, Sweden. www.globalhealthaction.net
The Umeå Centre for Global Health
Research is associated with the Division of
Epidemiology and Global Health at Umeå
University, Sweden, and is a Centre of
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