by Jasmine Kaur
One big factor of climate change that is reducing human performance and work capacity is heat exposure. Currently, in hot areas, 10% of daylight hours are too hot for work to be performed and by 2085, the loss of productivity working hours will have increased to 30-40%. The hot areas are Africa, Asia, Latin America, and at moderate risk are southeast and southwest United States. In these hot atmospheres the heat transfer of the intrabody to the external environment and away from the body is limited. The influence of heat exposure is causing the core body temperature to rise that leads to serious physiological risks. Mainly affected are the cardiovascular system with limitations of blood flow, increased heart rate, and conspicuous sweating. As climate change progresses the incidences of occupational health problems will rise, and labor productivity and work capacity will fall.
The impacts of these losses vary depending on job intensity, environment, and general location. An instrument that is helpful to assess the heat exposure is the WBGT. The WBGT (wet bulb globe temperature) is a measure of temperature, humidity, wind speed, and heat radiation combined to directly assess the heat transfer rate from the body. In an hourly WBGT of 79°F, heavy labor work capacity is reduced, and a WBGT higher than 90°F, means work productivity is extremely demanding. Excessive heat exposure affects the individual’s performance and productivity, and further adversely affect the community and economy. Farmers carry out 80% of the physical labor needed to sustain agriculture resources for low- and middle-income countries. There have been suggestions to limit worker’s heat exposure by implementing machinery to substitute for human labor. However, the solution offered ignores the lack of financial resources of the developing countries where these problems are arising.
Effects of heat exposure on work activity are most vulnerable to the low-income populations of tropical and subtropical areas. Workplace heat for outdoor occupations, which include construction work, open cast mining, transportation, and community services lead to the problems caused by heat exhaustion. Similarly, indoor occupations that lack air-conditioning such as factory and work-shop buildings, face extreme heat exposure on a daily basis in these hot low-income countries. Often heat strain is ignored, as work productivity is seen as more important than the physiological conditions of the workers. The duration of heat exposure may vary health outcomes from a minimum of heat exhaustion kicking in within an hour of working to a maximum of undernutrition and mental stresses showing up years after the labor was performed. Kjellstrom et al. (2016) made estimates of the increasing workplace heat on global and regional areas based on climate change using the WBGT index. They estimated a total global gross domestic product (GDP) loss of US$2.1 trillion in 2030 and a second loss of 23% of global GDP in 2100, with low-income tropical regions being the most affected. To improve the community adaptations to the increased heat levels in hot low-income areas, the next step is to expand the field studies on the physiological impacts that climate change has on occupational health issues.
Kjellstrom, T., Briggs, D., Freyberg, C., Lemke, B., Otto, M., & Hyatt, O. (2016). Heat, human performance, and occupational health: a key issue for the assessment of global climate change impacts. Annual review of public health, 37, 97-112.