Climate change impacts on heat stress in Brazil—Past, present, and future implications for occupational heat exposure

Abstract

Climate change has caused an increased occurrence of heat waves. As a result of rising temperatures, implications for health and the environment have been more frequently reported. Outdoor labour activities deserve special attention, as is the case with agricultural and construction workers exposed to extreme weather conditions, including intense heat. This paper presents an overview of heat stress conditions in Brazil from 1961 to 2010. It also presents computersimulated projections of heat stress conditions up to the late 21st century. The proposed climate analysis drew on historical weather data obtained from national weather stations and on reanalysis data, in addition to future projections with the ETA (regarding the model's unique vertical coordinate) regional forecast model. The projections took into consideration two Representative Concentration Pathways (RCP)-the 4.5 and 8.5 climate scenarios, namely, moderate and high emissions scenarios, respectively. Heat stress was inferred based on the wet-bulb globe temperature (WBGT) index. The results of this climate analysis show that Brazilian outdoor workers have been exposed to an increasing level of heat stress. These results suggest that future changes in the regional climate may increase the probability of heat stress situations in the next decades, with expectations of WBGT values greater than those observed in the baseline period (1961-1990). In terms of spatial distribution, the Brazilian western and northern regions experienced more critical heat stress conditions with higher WBGT values. As a response to the increased frequency trends of hot periods in tropical areas, urgent measures should be taken to review public policies in Brazil. Such policies should include actions towards better working conditions, technological development to improve outdoor labour activities, and employment legislation reviews to mitigate heat impacts on occupational health.

Deforestation and climate change are projected to increase heat stress risk in the Brazilian Amazon

“…Additionally, increased heat stress exposure might impact several areas of the economy via effects on labor productivity, as workers will be exposed to fatal thermal conditions. In Brazil, outdoor workers are already exposed to heat stress, and the projections indicate increasing high-risk exposure over the next decades 34,35 . The 1.5 °C increase in the global average temperature based on the projections of HadGEM2 and GFDL-ESM2M climate models could represent 0.84% of losses in working hours by 2030, the equivalent of 850,000 full-time jobs, especially in the agricultural and construction sectors 36 .…”

The heat wave of October 2020 in central South America

“…Climate projections indicate a continuing intensification of these extreme events in a separate mode and, particularly, in a compound manner, and climate change would make heat waves to be more exacerbated or accentuated in urban areas or mega-cities due to the formation of local heat islands (IPCC, 2013;Hao et al, 2018;Geirinhas et al, 2021). Future projections of heat waves (Feron et al, 2019;Bitencourt et al, 2020) suggest that the number of heat waves per season is expected to increase, particularly in tropical areas where half or more of the days could be extremely warm by mid-century, with a higher probability of heat stress situations in the coming decades, particularly over northern and western regions of Brazil. Vogel et al (2020) use Coupled Model Intercomparison Programme Version 6 (CMIP6) models and show that the risk of 'extreme extremes' (compound events) strongly increases with higher global warming levels.…”

Kidney Function in Factory Workers Exposed to Heat Stress

“…5,6 In Brazil, although this topic has not been explored, it is very likely that CKDu is an important cause of CKD, because workers in our country have been exposed to extreme heat conditions that have increased in the last decades because of climate change. 2 Although the relationship between occupational heat stress and kidney health in outdoor workers has been more fully explored, there is a paucity of data on indoor workers. Millions of them may be at risk worldwide, particularly those working near furnaces, ovens, smelters, and boilers in kitchens, steel plants, foundries, automobile industries, and glass manufacturing units.…”

“…Heat stress is the sum of the heat generated in the body (metabolic heat), plus the heat gained from the environment (environmental heat), minus the heat lost from the body to the environment 1 . Workers exposed to hot environments or those engaged in strenuous physical activities even at mild temperatures may be at risk for heat stress 2 . Occupational heat stress affects both outdoor and indoor workers who perform activities in hot environments 3 and can result in reduced productivity, injuries, disease, and death 1…”

“…Since 1990, CKDu has accounted for tens of thousands of deaths among working-age people in Mesoamerica, Eastern Asia, and other hot regions 5,6 . In Brazil, although this topic has not been explored, it is very likely that CKDu is an important cause of CKD, because workers in our country have been exposed to extreme heat conditions that have increased in the last decades because of climate change 2 …”