Climate change represents an unprecedented global challenge and negatively influences virtually all lives on the planet, affecting it in different proportions and with diverse consequences (HUSSAIN et al., 2020; IPCC, 2014). In human life, the impacts of these changes can be reflected on an environmental, social, economic, and political scale, with direct consequences on the health and safety of the population, on the availability of natural resources, on the existence of different types of labor and even on the diplomatic relationship between countries (ADAM-POUPART et al., 2013b). Workers represent a demographic group quite vulnerable to these changes, both concerning the jobs' availability or the adverse impacts on the population's health. Climate change's harmful effects, often avoidable by the overall population, damage these individuals during their occupational activities (KIEFER et al., 2016; SCHULTE; CHUN, 2009).
The choice to apply the methodology of systematic mapping collaborated to achieve the study's objectives, making it possible to establish a knowledge base on how the subject has been discussed in the global academic sphere and elucidating how, and for what purposes, international publications have been developed. It was possible to distinguish different possible paths from techniques already used successfully and replicable to gaps still little explored.
With 170 analyzed articles, this mapping made it possible to understand some aspects that characterize this topic of research and accomplish two main academic contributions: the first concerns the structure of the articles, discussing the most practiced methodological ways to deal with the issue of effects of climate change on workers, highlighting methods with active use of data collection and field studies; the second contribution, on the other hand, is associated with the most significant impacts of climate change discussed in the literature, identifying which ones represent the primary research concern and what are their consequences for workers. We believe that, by highlighting the main research methods used, this study can guide future research both concerning methodologies that have been scientifically well-founded and successfully applied previously, as well as to techniques little-used with space for more significant contributions. Similarly, by highlighting the significant impacts of climate change on workers, this study contributes to guiding how the literature has been investigating these risks, which methodologies work, and how to obtain success in analyzing this type of impact. It also collaborates in identifying potential risks that are still little explored and with room for research development.
In more detail, the methodological approach most present was the use of secondary data collected from workers' or meteorological databases to base the research. A usual method was to investigate the number of accidents or occupational diseases in a given region or industrial sector during a specific time compared to temperature variations and climatic conditions in the same period, checking for a possible influence of heat in increasing these occupational events. Another approach involved collecting primary data to investigate the increase in workers' accidents or illnesses with climatic conditions. It was the case of temperature measurement in the workplace and even medical examinations to monitor workers' physiological conditions during work activities.
These two categories of methodologies most frequent in this mapping point to a trend in studies with applied research on climate change. And its impacts on workers' health, with a potential for quantitative and qualitative approaches, using secondary databases on a large scale - regional or national - combining occupational information with meteorological data to carry out the analysis. Simultaneously, it is possible to make a primary data collection to improve this analysis closer to reality. In the opposite direction, studies of a more fundamental nature appeared less frequently in this mapping, which can be seen as a potential for expanding the literature, highlighting the absence of systematic mappings within this analysis, which makes this study feasible.
Another gap perceived by this study is related to the countries of application of this type of research. There was a greater quantity of articles for more developed countries, such as Australia, Canada, the United States of America, and an excellent deficiency for less developed countries, mainly African countries, Latin America, the Middle East, and South Asia. In addition to the fact that these countries are mostly less developed - which already indicates that their population can be even more vulnerable to climate change. They are still almost all tropical and sub-tropical countries, located in the world's hottest regions and most susceptible to rising temperatures and other climatic changes.
Therefore, there is a potential for research expansion to these regions.
Regarding the impacts and consequences found in this mapping, what stood out most among the studies, representing about 86% of the articles, was the increase in temperatures, with their effects ranging from increased kidney diseases, increased accidents and injuries, even an increase in the mortality of workers. One of the advantages of this large number of articles aimed at investigating the effects of heat on workers is that. In addition to proving the adverse effects of high temperatures on these individuals, they also contribute by demonstrating ways to carry out this approach successfully. An example of this is the use constant of the globe thermometer wet-bulb index (IBUTG), in English Wet Bulb Globe Temperature (WBGT), to evaluate human heat tolerance limits. On the other hand, a lack of research focused on the different effects of climate change, such as air pollution, increased vector-borne diseases, the greater incidence of extreme weather events, and all the others. This gap opens the door for expanding the literature, with research explicitly focused on these impacts.
It is also possible to argue that there is a greater frequency of studies on the impacts of climate change for workers in sectors considered outdoors, emphasizing this mapping on the sectors of agriculture and civil construction. There was also a focus on industrial activities involving processes that generate heat, such as ceramic production and metallurgy. Although they were the most frequent in this mapping, these sectors can still be expanded in the literature. The agriculture sector, for example, is quite broad and can vary a lot depending on the region being investigated. Being able to investigate the production and harvest of fruits in the United States (QUILLER et al., 2017), the health of sugarcane cutters in El Salvador (BODIN et al., 2016), or even the diseases of cocoa farmers in Nigeria (OYEKALE, 2015). Therefore, while it is possible to affirm that there is a gap in studies investigating the relationship between climate change and other industrial sectors, there is still potential for expansion for those most mentioned in this mapping, especially if combined with the investigation of further climate changes. Other than rising temperatures or in countries that have not yet been studied.
Future research opportunities include more theoretical studies, capable of drawing a comprehensive profile on the issue and serving to guide other research. In this regard, tasks such as the one by Adam-Poupart et al. (2013) and Schulte et al. (2016) are welcome. A framework is created, condensing all the information about the possible impacts caused by climate change to workers. Especially if the study's focus is specific to a region, considering climatic variables, economic and social issues relevant to that part of the world. Systematic studies, such as reviews and mappings, also have a space of opportunity, significantly articles with a more specific focus on a particular problem, such as those that address a particular impact or a different industrial sector. A few pieces in the discussion and synthesis categories dealt with climate change's effects unrelated to the increase in temperatures. Many brought a much more generalized approach to the subject. Research aimed at other impacts, such as extreme weather events, changes in precipitation patterns, or even an increase in vector-borne diseases, are necessary to make the literature and the debate on this health problem even more vast and complete.
It is worth highlighting some limitations found for the production of this mapping. First, even though one of the articles' selection criteria is limited to English and Portuguese, none of the 170 selected articles were written in Portuguese. Only articles in English can define the global analysis of this topic and skew the results towards countries whose native language is English. Many can see this of articles distributed between Australia, Canada, the United States, and India. Simultaneously, regions such as Latin America, mainly composed of countries whose native language is Spanish, had very little representation in the study. This problem can be solved by setting up a research team consisting of researchers fluent in other languages. Also, it is possible that the way the string search was constructed, including keywords for climate change in general, is not able to collect all existing articles on the topic, especially those that specifically address just one impact alone. However, a search strategy that includes keywords for each of the potential effects of climate change represents more and more articles for analysis, making the mapping process long and demanding.
