Lemke B

The WBGT heat stress index has been well tested under a variety of climatic conditions and quantitative links have been established between WBGT and the work-rest cycles needed to prevent heat stress effects at the workplace. While there are more specific methods based on individual physiological measurements to determine heat strain in an individual worker, the WBGT index is used in international and national standards to specify workplace heat stress risks.

Climate conditions in workplaces are occupational health hazards that need to be taken into account when assessing population vulnerability to climate conditions and climate changes. Very cold as well as very hot work environments can create thermal stress beyond what human physiology can cope with. All human populations have a normal core body temperature in the range 36–37 °C, and even a few degrees higher or lower body temperature, due to surrounding climate conditions, can lead to serious health effects.

While climate change continues to increase ambient temperatures, the resulting heat stress exposure to workers in non-climate controlled settings is not well characterized, particularly in low and middle income countries. This preliminary report describes current heat stress in Nicaraguan work places and estimates occupational heat stress in 2050. From over 400 measurements of heat exposure using wet bulb globe temperature, more than 10% of all measurements exceeded the safety threshold for the combination of light work and rest at the ratio of 25:75.

A feature of climate impacts on occupational health and safety are physiological limits to carrying out physical work at high heat exposure. Heat stress reduces a workers work capacity, leading to lower hourly labour productivity and economic output. We used existing weather station data and climate modeling grid cell data to describe heat conditions (calculated as Wet Bulb Globe Temperature, WBGT) in South-East Asia.

This chapter describes the 5 components of heat exposure and effect studies in workplace settings: a descriptive pilot study; heat monitoring studies; exploratory interview surveys; quantitative studies of heat exposure-response relationships; and occupational health and economic impact assessment for local climate change. These components can be carried out separately or in combination and the results of local studies can be used to improve occupational health protection actions and can contribute to the global assessments of climate change impacts.

This chapter discusses the role of climate change in increasing workplace heat exposures and the association of human physiology and performance with ambient heat exposure. The clinical effects of heat exposure as well as its economic and well-being impacts are described. Preventive actions are suggested.

A number of aspects of human health are caused by, or associated with, local climate conditions, such as heat and cold, rainfall, wind and cloudiness. Any of these aspects of health can also be affected by climate change, and the predicted higher temperatures, changes in rainfall, and more frequent extreme weather conditions will create increased health risks in many workplaces. Important occupational health risks include heat stress effects, injuries due to extreme weather, increased chemical exposures, vector-borne diseases and under-nutrition.

Summary Extreme heat induced by climate change will cause profound adverse consequences for work, human performance, daily life, and the economy in large parts of the world. The increasing temperatures are the most predictable effects of climate change, and all models of future trends show significant increase this century. The heat problems will become even worse in the next one or two centuries, depending on the global climate policies established this year. The global areas worst affected by extreme heat will be tropical countries,

First paragraph of book chapter: The human body has behavioural and physical mechanisms that work to maintain its core temperature at about 37°C. If the body’s internal temperature rises above this level, then body systems and vital physiological functions are compromised, and in severe cases, death can result. The climatic conditions relevant to such heat stress may be measured in terms of the Wet Bulb Globe Temperature (WBGT), which takes account of temperature, humidity, wind speed, and solar radiation.1 We calculate WBGT for in-shade (no

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