Climate Change Effects on the Predicted Heat Strain and Labour Capacity of Outdoor Workers in Australia

Abstract

Global heating is subjecting more of the planet to longer periods of higher heat stress categories commonly employed to determine safe work durations. This study compared predicted worker heat strain and labour capacity for a recent normal climate (1986–2005) and under commonly applied climate scenarios for the 2041–2080 period for selected Australian locations. Recently published heat indices for northern (Darwin, Townsville, and Tom Price) and south-eastern coastal and inland Australia locations (Griffith, Port Macquarie, and Clare) under four projected climate scenarios, comprising two representative concentration pathways (RCPs), RCP4.5 and RCP8.5, and two time periods, 2041–2060 and 2061–2080, were used. Safe work durations, before the threshold for core temperature (38.0 °C) or sweat loss (5% body mass) are attained, were then estimated for each scenario using the predicted heat strain model (ISO7933). The modelled time to threshold core temperature varied with location, climate scenario, and metabolic rate. Relative to the baseline (1986–2005), safe work durations (labour capacity) were reduced by >50% in Port Macquarie and Griffith and by 20–50% in northern Australia. Reaching the sweat loss limit restricted safe work durations in Clare and Griffith. Projected future climatic conditions will adversely impact the predicted heat strain and labour capacity of outdoor workers in Australia. Risk management strategies must adapt to warming conditions to protect outdoor workers from the deleterious effects of heat.

Broad Scale Spatial Modelling of Wet Bulb Globe Temperature to Investigate Impact of Shade and Airflow on Heat Injury Risk and Labour Capacity in Warm to Hot Climates

“…Modelled low summer daytime labour capacities across much of the continent for the baseline 1986-2005 period in conjunction with projected future WBGTs under climate change scenarios indicate that labour capacities across much of Australia are expected to decline for larger areas and greater proportions of the year, which is concomitant with physiological modelling for future Australian heat-exposure conditions determined by Hunt, Brearley, Hall and Pope [11]. This outcome is similar to that demonstrated for population centres of Brazil, which are subject to increasing heat categories comparable to Australia, increasing probability of heat stress across Brazil in coming decades with distinct spatial variation in rates of change [16,38].…”

“…The International Standards Organisation adopted WBGT as the metric to describe heat exposure in 1982 [9,10], and it is applied in many outdoor work situations to assess heat exposure risk for persons conducting physical 2 of 17 activity outdoors. Both the level of physical activity and WBGT are used to determine limits on physical work time and maintain a safe internal body temperature [11].…”

Climate change and heat stress resilient outdoor workers: findings from systematic literature review

“… 32 28 Butt et al, 2022 [ 48 ] Pakistan Review Different jobs N N Adaptation policies are required to acclimatize the workers in hot climate conditions. 23 29 Hunt et al, 2023 [ 13 ] Australia Cross-sectional Different jobs N WBGT Risk management strategies must adapt to hot climate conditions to protect outdoor workers from the effects of thermal stress. 32 WBGT = Wet Bulb Globe Temperature; Tc = Core Temperature; HR = Heart Rate; LCG = Liquid Cooling Garments; Tsk = skin temperature; Ta = Dry Temperature; PSI = Physiological Strain Index; RPE = Ratings of perceived exertion; RH = Relative Humidity; HRI = heat-related illness; SWreq = Required Sweat Rate; N = Not Mentioned …”

“…Increased exposure to thermal stress among workers in outdoor environments has been documented in tropical and subtropical countries with hot seasons [ 11 ]. Exposure to hot working environments, and the resulting elevated physiological and perceptual responses, can lead to occupational heat stress, reducing safety, health, and work capacity [ 12 ], and increasing the risk of heat-related illnesses (HRI) [ 13 ]. The increment in the levels of ambient temperature, radiation and shifts in the distribution of daily peak temperature can cause indirect and direct effects on outdoor workers [ 14 , 15 ].…”

Impacts of Climate Change on Work Health and Safety in Australia: A Scoping Literature Review

“…Looking ahead to 2041-2080, Hall et al [8] examined the likely impacts of climate change on Wet-Bulb Globe Temperatures (WBGT) in summer and winter across Australia to gauge the extent to which outdoor physical work capacity and risk of heat injury may be affected. Based on that work, a WBGT increase of 2-3 • C is predicted in the tropics and mid-latitudes in the 21st century, and workers are at increased risk of productivity loss and heat illness [14]. In Australia, heat is responsible for over 1100 deaths per year, which presents the highest risk among natural hazards and a risk exceeding the annual road toll [15].…”