Climate Change: Impact on Occupational Safety and Health (OSH)

Introduction

Human health has always been influenced by climate and weather. Changes in climate and climate variability lead to extreme weather conditions and affect the environment that provides humans with clean air, food, water, shelter, and security ^[1] .
The influences of climate on human health are significant and varied. The exposure pathways differ over time and according to the location. Moreover, climate change-related exposures may affect different people and different communities to different degrees. Climate change threats may also accumulate over time, leading to longer-term changes in resilience and health ^[1].
Occupational Safety and Health (OSH) is also influenced by climate change through higher ambient temperatures, indoor and outdoor air pollution, ultraviolet radiation exposure, extreme weather effects, etc. leading to effects such as heat disorders, vector-borne and water-borne diseases, accidents, cancer, production losses, etc. Understanding the threats posed by climate change to safety and health at work is necessary in order to assess and manage the risks.

Climate Change

Global climate change

Climate change is one of the most important issues of our time and a challenge facing future generations. The World Health Organisation COP24 Special Report described climate change as “the greatest health challenge of the 21^stcentury, with major threats to life, health and well-being” ^[2]. In 1992, climate change was defined as “a change of climate that is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is an addition to natural climate variability observed over comparable time periods” ^[3]. Climate change, “change in the state of the climate that persists for an extended period”, is part of “global environmental change” ^[4][5]. In 2019, Solomon et al. declared in the journal New England Journal of Medicine climate change “a health emergency”  ^[6].

The International Panel on Climate Change (IPCC),  the United Nations body for assessing the science related to climate change, identified some evidence of actual human health effects directly affected by climate change (e.g. heat stress, death or injury from floods, wildfires and storms), and indirectly through changes in the ranges of disease vectors (e.g. mosquitoes), waterborne pathogens, water quality, air quality, and food availability and quality ^[7][8]. Climate change has the potential to affect human health in several ways, for instance by altering the geographic range and seasonality of certain infectious diseases, disturbing food-producing ecosystems, and increasing the frequency of extreme weather events ^[9]. The changes that climate can cause are in the form of acute weather events or natural disasters that last for days (hurricanes, wildfires, floods, short-duration heat waves), subacute events lasting for months or a few years (droughts) and long-lasting changes, such as higher temperatures, widespread melting of glaciers, rising seas levels and potentially uninhabitable physical environments due to permanent alterations ^[10].

Climate Change in Europe

A significant proportion of Europe lies in the northern latitudes. The relatively warm seas that border the continent give most of Central and Western Europe a temperate climate, with mild winters and summers. The winds from the west bring precipitation throughout most of the year. In the Mediterranean area, the summer months are usually hot and dry, with almost all rainfall occurring in the winter. By contrast, from central Poland eastwards, the moderating effect of the seas is reduced. Meanwhile, north-western Europe is characterised by comparatively mild winters, with high precipitation along the mountainous coasts. The average temperature in Europe has increased continuously since the turn of the twentieth century. However, there are different rates of warming across Europe. Also, since 1950, high-temperature extremes (hot days, tropical nights, heat waves) have become more frequent, whereas the opposite is true of low-temperature extremes. Looking forward, climate models indicate that the climate of the 21^st century will be warmer all over Europe, with the strongest warming projected to occur in Southern Europe in summer and in Northern Europe in winter. It is expected that there will be a marked increase in the incidence of heat waves, droughts, and heavy precipitation events ^[11].

Effects of climate change

Health effects

The scientific literature on climate change has been focused mainly on public, non-occupational, health as well as on the role of natural and anthropogenic factors ^[12][13][14]. Climate change poses serious risks to human health, causing injuries and increasing the risk of both communicable and non-communicable diseases by affecting different systems in the human body, including the respiratory, the cardiovascular and the central nervous system.
The OSH literature mainly refers to heat stroke episodes and occupational accidents due to or promoted by extreme temperatures. However, both climate change and OSH are two complex and multidisciplinary topics, requiring different and complementary expertise.
Workers may serve the function as “canaries in the coal mine” of climate change effects ^[15]. Several studies have highlighted the effects of climate change on workers and workplaces. Outdoor workers are the most vulnerable ^[16]. The main outdoor sectors that are directly affected are agriculture, fishing, and forestry ^[17] . Yet  the climate change effects accumulate across all sectors of industry, such as emergency response (for more information on OSH in emergency services, see EU-OSHA report Emergency services: occupational safety and health risks ^[18]), water supply, energy, transportation, construction, etc. ^[19] [15].

Framework for describing the effects on workers and workplaces

Will the effects on workers be different from the general population? Will work potentiate the health effects of climate change? The effects of climate change on OSH are likely to increase the prevalence, distribution, and severity of exposure to known hazards and result in increased incidence, mortality and injury. In addition, new risks may emerge as a result of the interaction of known hazards with changed conditions. The impact on workers' health is difficult to determine as workers' health status is influenced not only by work-related factors but also by factors such as employment status, income, and access to health services ^[8].

To begin to address these complex questions, Schulte & Chun developed a conceptual framework in 2016 for identifying how climate change could affect the workplace, workers, and occupational morbidity and mortality ^[20]. The review has identified seven categories of climate-related occupational hazards and two additional OSH-related topics based on the published peer reviewed scientific literature from 1988-2016. These are: 1) increased ambient temperatures, 2) air pollution, 3) ozone depletion leading to increased ultraviolet (UV) radiation, 4) extreme weather, 5) vector-borne diseases/expanded habitats, 6) hazards caused by industrial transitions and emerging green industries (solar and wind energy production), 7) hazards caused by changes in the built environment, 8) mental health issues(anxiety, stress, substance abuse), and finally 9) economic burden ^{[20] [8] [21]}. Each of these nine categories are explained further in the paragraphs below.

In addition, the review identified areas where OSH could address occupational risks: adaptation of standards, modification and improvement of risk controls including personal protective equipment (PPE), development of acclimatisation procedures, new research directions, development of new guidance for risk management and risk communication, development of early warning systems and surveillance, and more emphasis on prevention through design ^[20] [8].

Increased ambient temperatures

Heat is an occupational safety and health hazard. Many workers spend their entire work shift in a variety of outdoor and indoor hot environments that may become hotter because of rising ambient temperatures, increases in extreme heat events, or shifting and expanding hot seasons ^[20]. Job conditions such as performing physically demanding tasks or wearing respiratory protective equipment can further increase the risks  ^[16].

Heat stress (i.e., the sum of metabolic heat plus environmental heat, minus the heat lost from the body to the environment) can result in a cascade of discomfort and dehydration, but also many heat-related illnesses such as heat stroke, heat exhaustion, heat syncope, heat cramps, heat rash, or heat-related death ^{[12][13] [20] [22][23][24]}. The risk may be increased through lack of heat acclimatisation, low physical fitness, dehydration, increasing age, high body mass index, underlying health conditions, and certain medications^[25].

Temperature extremes most directly affect health by compromising the body’s ability to regulate its internal temperature. Temperature extremes can also worsen chronic conditions such as cardiovascular disease, respiratory disease, cerebrovascular disease, and diabetes-related conditions ^[24]. More hospital visits and higher mortality caused by coronary heart disease and stroke, the two major cardiovascular diseases, due to increased ambient temperatures have been reported. Workers with pre-existing cardiovascular disease and older workers are at increased cardiovascular risk ^[26]. Individuals with impaired cardiovascular function have a limited ability to increase stroke volume, cardiac output, and blood flow to the skin, increasing the risk of heat stroke. In turn, people whose cardiac condition is already compromised are susceptible to cardiovascular complications of heat stroke, including arrhythmias, myocardial ischemia, heart failure, shock, and sudden death. Indeed, most excess deaths during heat waves are cardiovascular in origin, highlighting the impact the cardiovascular system has on the development of heat stroke, and vice versa ^[27].

Several epidemiological studies have repeatedly demonstrated that hot weather (and particularly heat waves) contributes to excess morbidity and mortality but very little is known about the effect on work related injuries^[28][29]. Heat exposures can increase the risk of workplace injuries, such as those caused by sweaty palms, fogged-up safety glasses, dizziness, and reduced brain function. Excess heat reduces work capacity and productivity in heat-exposed jobs and may result in more accidents. In particular, the reduction of cognitive abilities  (vigilance) and the extension of reaction times results affect work safety in the case of high-risk tasks (e.g. drivers) ^[22].

Meteorological conditions can also affect the physiological response to toxicants through their effects on thermoregulation, including skin blood flow, sweating, and respiration. Warm, wet skin promotes the absorption of chemicals ^[20]. Changes to the body’s core temperature can alter the absorption, distribution, metabolism, and excretion of toxicants, such as pesticides. Increases in respiration can lead to additional toxicant exposure through inhalation and increases in sweat and skin blood flow can lead to more efficient transcutaneous absorption of toxicants. High temperatures may also accelerate dispersion of pesticides and increase the density of airborne particles. Some workers may be more likely to not use PPE, or not use it correctly because of discomfort from the heat. Workers in agriculture, for instance, have potentially increased exposure to pesticides when they are heat stressed. A few studies have indicated an association between high temperature and chemical intolerance, e.g. pesticide poisoning among agricultural workers and military personnel in hot environments ^[20]. Bourbonnais et al. studied the risks of simultaneous exposure according to heat and chemicals and found that workers in metal manufacturing, roofing and firefighters were particularly at risk ^[30].

Increased ambient temperatures not only affect human health but also influence the operations of industrial installations. High ambient temperature increases the risk of fires by fermentation or self-heating of material, products or waste, magnifying glass effects, but also by electrical  equipment overheating or by pressure rises. In France, over the last years, there has been a significant increase of industrial incidents during the summer periods with 64 events recorded for 2019, the year with the greatest impact. These 64 events occurred across all industry sectors but mostly in waste storage areas and waste treatment facilities ^[31].

Heat stress indices are used to assess hot environments and predict likely thermal strain on the body. More than 170 heat stress indices are described in the literature, but it is clear that no perfect index may cover all occupational heat stress scenarios. Within the ‘HEAT-SHIELD’ project ^[32], an EU funded project to increase the thermal resilience of European workers in the context of global warming, a heat stress index has been developed based on a modified ‘Wet Bulb Globe Temperature (WBGT) Index’ calculated from validated formulas, using weather station data from across Europe ^[33].

Air quality: indoor & outdoor pollution – Aeroallergens

Air pollution and climate change have a complex reciprocal relationship: various air pollutants increase global warming, and global warming leads to the formation of various pollutants.
The levels and location of outdoor air pollutants such as ground-level ozone (O₃), sulphates, organic and elemental carbon, and fine particulate matter smaller than 2.5 microns in diameter (PM_2.5), are influenced by climate change ^[34]. Increasing carbon dioxide (CO₂) levels also promote the growth of plants that release airborne allergens (aeroallergens). These changes affect indoor air quality as both pollutants (moulds, Volatile Organic Compounds (VOCs)) and aeroallergens infiltrate buildings^[34]. Most of the air people breathe over their lifetime will be indoors, thus, alterations in indoor air pollutant concentrations may have important health implications.

Ozone (O₃) is formed in the atmosphere as a result of photochemical reactions of VOCs and nitrogen oxides (NO_X) driven by sunlight. Warmer regions with more sunlight therefore tend to have higher ozone concentrations. Ozone concentrations are increasing and the ‘ozone season’, the period in which ground-level ozone typically reaches its highest concentrations in the air, is prolonged. Ground level ozone and rising temperatures trigger a variety of health problems (such as a reduction of lung function parameters, or more asthma development or exacerbation). Higher ozone concentrations may lead to more hospital visits, more acute respiratory symptoms, and premature deaths ^[34] [35].

Particulate Matter is a complex mixture of solid- or liquid-phase substances in the atmosphere that arises from both natural and human sources ^[34] . The principal constituents include sulphate, nitrate, ammonium, organic carbon, elemental carbon, sea salt, and dust. The particles in these aerosols can either be directly emitted or can be formed in the atmosphere from gas-phase precursors. Exposure to PM_2.5, the fraction of tiny particles or droplets in the air that are two- and one-half microns or less in width, is associated with serious acute and chronic health effects, including lung cancer, chronic obstructive pulmonary disease (COPD), cardiovascular disease, and asthma development and exacerbation.
The impact of ambient air pollution on workers has not been assessed comprehensively ^[20]. Outdoor workers in hot environments have increased respiratory rates and thus may be more affected by air pollution than other members of the general population. Temperature increases associated with climate change can also affect indoor workers’ exposure to air pollution during their work in offices or factories, or while travelling to and from work by car, bicycling or walking, and from pollutants in their outdoor work environment.
Outdoor air pollution and climate change have a central role in the aetiology and pathology of occupational allergies, triggered by the increase in length and severity of the pollen season ^[36].

Ultraviolet radiation exposure

The complex interaction of greenhouse gases, climate change, and stratospheric ozone depletion results in increased UV radiation that can affect all people, particularly outdoor workers (e.g., construction workers, fishermen, or farmers, who may develop skin cancer because they are exposed to the sun on a daily basis) ^[37].  Overexposure to UV radiation can also increase the risk of eye damage (e.g., cataracts and photokeratitis), skin and other cancers, sunburn, and even immune suppression.

Extreme weather events and natural disasters

Extreme weather events are expected to become more frequent and intense. Climate change is increasing the frequency and severity of many types of extreme weather such as windstorms, droughts, heatwaves, heavy precipitation and can cause natural disasters such as floods, landslides, avalanches, and wildfires  ^[35]. Both the extreme weather conditions and the natural disasters pose risks for outdoor workers but also for emergency responders and others involved in response, rescue, clean-up, and remediation. Moreover, during extreme weather events or natural disasters, emergency workers often have to work at maximum capacity while wearing personal protective clothing or equipment, which can cause additional mental and physical strain  ^[18]. Firefighters and other natural resource workers can be exposed to naturally occurring asbestos and/or erionite, fibrous mineral fibres that are potent carcinogens associated with high rates of malignant mesothelioma, during trail and forest road maintenance and, timber stand grading, when cutting fire lines, and while fighting wildfires.

Extreme weather events may also force workers to remain at the worksite and prolong work hours until replacements arrive, triggering mental fatigue that increases the risk of accidents.

Flooding with contaminated water, debris and disruptions to essential infrastructure, could result in drowning, injuries, mental health issues, gastrointestinal and other illnesses, and accidents. On the other hand, drier weather may generate soil- and dust-borne (e.g. silica dust exposure) diseases ^[18] [20].

Climate-sensitive vector-borne diseases and other related hazards

Considerable research regarding the impact of climate change on vector-borne diseases and other related hazards (venomous insects and reptiles, water-borne disease, non-vector borne pathogens, and poisonous plants) has been conducted. Some common allergic diseases are climate sensitive because warmer conditions favour airborne allergens (e.g. fungal spores, plant pollen, and moulds). Expanded ranges for poisonous plants may also have significant implications for outdoor workers. Outdoor workers are primarily at risk, including those in construction, landscaping, forestry, brush cleaning, land surveying, farming, oil field and utility work, natural resources management, and wildland firefighters ^[20]. Livestock may act as reservoir of biological agents, potentially resulting in global epidemics of zoonoses (Q-fever, tularemia), particularly relevant to animal-related work. Exposure to vectors such as mosquitoes, ticks and fleas that can transmit parasites, viruses, or bacteria, may cause serious diseases or outbreaks. Climate changes such as higher temperature and higher humidity influence vector-borne (e.g. tick-borne Lyme borreliosis) and water-borne transmission (e.g. leptospirosis during floods) through their effect on range, vector growth cycles, pathogen development within the vector and the introduction of new diseases into Europe ^{[38][39][40][41]}.

Water-borne diseases

Floods combined with abnormally warm sea surface temperatures favour cholera outbreaks caused by the bacteria Vibrio cholerae ^[40] as well as leptospirosis and gastrointestinal diseases. Waterborne diarrheal disease is sensitive to climate variability and can affect workers in occupations such as fishing and natural resource management.

Tick-borne diseases

For the two most important tick-borne diseases in Europe, Lyme borreliosis and tick-borne encephalitis (TBE), Ixodes ricinus (the sheep tick) is the primary vector. Ticks are susceptible to climatic determinants, specifically humidity and temperature. Ixodes ricinus is present throughout a large part of continental Europe, and there has been a documented expansion to higher latitudes and altitudes. There are reports of northerly movement in Sweden, and to higher elevations in Austria and the Czech Republic. Range expansions have also been described in Norway and Germany. Lyme disease risk has been linked to warm winters, elevated summer temperatures, low seasonal temperature variation and high vegetation indices. For TBE, the relative importance of climate change vis a vis other factors varies by location and is a function of immunisation coverage, tourism activity, human exposure, rodent host population density and socio-economic conditions. The future projections for the period 2040-2060 are that I. ricinus will extend to areas in Scandinavian and Baltic countries. In contrast, a contraction is foreseen in the Alps, Pyrenees, north-western Poland and the interior of Italy. TBE incidence is expected to become higher in some parts of northern and central Europe, and lower in the south of Europe ^[39].

Mosquito-borne diseases

Mosquitoes, which carry many diseases, are very sensitive to temperature changes. Warming of their environment boosts their rates of reproduction and the number of blood meals they take prolongs their breeding season and shortens the maturation period for the microbes they disperse. Locally transmitted epidemics of malaria, dengue and chikungunya have occurred in continental Europe over the past decade. Aedes albopictus (Asian tiger mosquito) can transmit dengue, chikungunya and Zika. Anopheles mosquitoes, although malaria was eradicated from Europe in 1975, are still widely established throughout. A. albopticus is expected to become more prominent in wetter and warmer conditions, including the south and east of the United Kingdom, the Balkan Peninsula and central Europe. In contrast, the mosquito is expected to diminish in regions where the climate is projected to become drier, such as in some areas of Portugal and Spain. The arboviruses causing Dengue, Zika, yellow fever, and chikungunya are transmitted by Aedesmosquito species. Aedes albopictus (the Asian tiger mosquito) and Aedes aegypti (the yellow fever mosquito) are thought to be their main competent vectors  ^[40]. Dengue is the most rapidly spreading mosquito-borne disease, with a 30-fold increase in global incidence over the past 50 years.
Human malaria is caused by five species of Plasmodium parasites and is transmitted by female Anopheles mosquitoes. The more temperate form, Plasmodium vivax, used to be prevalent in Europe, but control measures such as drainage of marshes and spraying of diclorodiphenyltrichloroethane (DDT) led to its disappearance following World War II  ^[40]. Anopheles mosquitoes need adequate rainfall to create breeding sites that will not dry up or wash away over a 9 to 12 day period. Replication of the parasite requires a minimum air temperature of about 15-16°C for P. vivax.
Integrated surveillance of human cases and invasive and endemic mosquito species will be a cornerstone for effective prevention and control of vector-borne diseases ^[39]. Preventive measures for outdoor workers that lower the rate of mosquito stings include: eliminating mosquito breeding sites, wearing light-coloured long-sleeved clothes and trousers, tucking pants into socks or boots, and applying insect repellent.

Sandfly-borne diseases

Temperature and relative humidity affect the survival and reproduction rate of sandflies, and parasite development, and thus climate change could shift the range of leishmaniasis in the future. In Europe, leishmaniasis is the most prevalent disease transmitted by phebotomine sandflies, which is caused by two parasites: Leishmania infantum, responsible for visceral leishmaniasis, and Leishmania tropica, responsible for cutaneous leishmaniasis.
L. infantum, responsible for visceral leishmaniasis, is endemic in the Mediterranean area, while L. tropica, responsible for cutaneous leishmanisasis, arises periodically in Greece and neighbouring countries. The transmission of these two parasites is highly influenced by temperature. In Europe, support for contribution of climate change on the distribution of sandflies is limited  ^[39].

Industrial transitions and emerging industries

“Green industries”, the economies striving for a more sustainable pathway of growth, by undertaking green public investments and implementing public policy initiatives that encourage environmentally responsible private investments, will see substantial growth due to the support they receive as climate change mitigation measures. The use of green technologies may lead to exposure to traditional hazards or new combinations of traditional hazards in new occupations and/or industries (e.g. slips, trips and falls, musculoskeletal disorders, chemical exposures), or the emergence of previously unidentified hazards (for more information on OSH and green jobs, see EU-OSHA Workers’ safety and health in green jobs ^[42]). The transition period of adapting to the new economic environment might be associated with job insecurity, job loss, economic migration, and additional training needs ^[43].

Solar and wind energy production

Solar and wind energy production have seen rapid growth, and biofuel production and hydropower also contribute to overall electrical energy generation. New unique occupational hazards have been identified in the construction, operation, and maintenance of the facilities. For instance, wind energy workers may be exposed to risks during different phases of a wind farm project. Many of the tasks involved in erecting, maintaining and possibly dismantling wind turbines involve risks such as working at height or in confined spaces, manual handling or electrical hazards. The working conditions create unique challenges such as working in remote areas, extreme weather conditions or working at sea (for example in offshore wind parks). New technologies or work processes related to wind energy also cause new hazards, which require new combinations of skills to tackle them ^[44].

The ‘circular’ economy

Adapting to climate change is also expected to lead to a growth of the recycling industries since this contributes to the reduction of energy use, which translates into fewer fossil fuels burned and reduced emissions of greenhouse gases.  The circular economy refers to the circular flow and efficient (re)use of resources, materials and products. The life of products and materials is extended and waste is minimised. Products and industrial processes are designed to keep resources in use, and any unavoidable waste or residues are recycled or recovered ^[45] .

A circular economy makes use of various strategies such as reducing, re-using and recycling that together eliminate waste, lower material and resource consumption and reduce greenhouse gas emissions. By its nature, a circular economy will have lower carbon emissions than a linear economy. Producing new materials results in CO₂ emissions, circular economies minimise the need for producing new materials. Therefore, circular economy is crucial for reaching the climate goals. Transitioning to a circular economy is a key driver of the EU goal of achieving carbon neutrality by 2050 while creating sustainable growth and jobs (the Green Deal, see below) ^[46]. It has significant policy and regulatory implications that will affect future jobs. It will also have consequences for workers’ safety and health. For example: its impact on jobs in hazardous sectors, related to maintenance and repair, disassembly and recycling, could have a negative impact on working conditions; changes in organisational processes and/or redesigning tasks could have an impact on job content and satisfaction ^{[45] [47]}. The policy brief from EU-OSHA on the circular economy and the possible implications for future waste sector workplaces uses four scenarios to explore the effects of the implementation of a circular economy on OSH. The scenarios show that the waste sector will play a pivotal role in the future developments of the circular economy. The green transition will be a challenging, complex undertaking requiring the integration of new technologies. This will necessitate the reskilling of workers in the waste and recycling industries providing opportunities to significantly improve OSH practices and outcomes for workers if OSH considerations are made an inherent part of this process from the beginning ^[48]. Integrating OSH considerations into the further evolution of the circular economy is important as the waste and recycling sector is a high-risk sector. Recycling centre workers may be exposed to a wide range of occupational risks: acute injuries, elevated exposure to heavy metals in electronic waste recycling workers, and exposure to biological agents in recycling of domestic waste including plastics, textiles, and paper products ^[20] [49].

Changes in the built environment

Climate change has implications for the built environment and the workers involved with it (construction, forestry, landscaping). To improve the preparedness of buildings to climate change, new standards are applied with regard to energy-efficiency, structural integrity, circular economy principles, etc. (See: Level(s), European framework for sustainable buildings ^[50]). Construction and landscaping workers may be confronted with new techniques and experience new types of settings (e.g. insulation techniques, cooling installations, green roofs), which may increase the risks to their safety and health.

Furthermore, the tendency to improve energy-efficiency levels of buildings (“Green building movement”) can lead to sealed buildings and thus affecting the indoor exposure of workers, especially in offices, to air pollutants (Radon, VOCs, moulds).

Mental health effects of climate-related occupational hazards

The link between extreme weather events and natural disasters such as floods, forest fires, heat waves, cyclones, and extreme anxiety reactions is well established. Climate change may present acute and chronic stressors that may cause severe mental health problems. So, there are both direct and indirect effects of climate change on mental health: mental distress, anxiety, mood disorders, stress, post-traumatic stress disorder (PTSD), substance abuse, domestic violence and depression after acute events. Workers in a drought area may have combined psychological stress from the weather in general as well as from the effects of heat exposure. The loss of workers’ homes and property in floods could affect workers’ ability to concentrate and do work tasks safely. Long periods of high temperatures, heat, and drought put significant stress on communities that will be felt by workers in their jobs. Moreover, the loss of work capacity may result in loss of income that likely causes mental health stress in some workers ^{[20] [10] [51]}. Managing the mental distress caused by climate change, adapting production to the changing temperatures and rainfall patterns and finally coping with heat, new diseases, droughts or natural disasters are future challenges for farmers and foresters.  A wide range of psychological symptoms and disorders among farmers such as anxiety, mood disorders, stress, depression or the feeling of hopelessness, fear, despair, suicide ideation, increased drug abuse and heat-related deaths have been linked to adverse climatic changes. The relationship between climate change and the mental health of farmers is still under-investigated. Weather events together with financial pressures and shame campaigns (blaming farmers for the detrimental effects on health, the environment and animal welfare by doing their jobs) may cause different emotional responses, aggressive behaviour, and even increased suicide rates ^{[17]  [52]}.

Economic burden of climate-related OSH hazards

Based on a literature review, Seppänen et al. concluded that there is on average a 2% decrement in work performanceper degree C temperature rise, when the temperature is above 25 C° ^[53]. Workers engaged in heavy labour or working in humid and poorly ventilated conditions face increased risk of heat stress and are likely to suffer reduced performance and work capacity as consequences. So, there are potentially substantial economic consequences for workers, enterprises and the society as a whole. Many effects of climate change on workers are possible even without disabling health symptoms, especially in work capacity and productivity ^[22]. The physiological basis for the reduction of human performance and work capacity (or labour productivity) is well known, but it is not sufficiently taken into account when assessing the effects of climate change Kjellstrom ^[33]. Limiting working hours to reduce exposure to excessive heat outdoors has great influence on economy. Indoor heat reduction in buildings and cars involves high energy costs (e.g. air conditioning, infrastructure adaptations). Air conditioners do great good, but at high environmental and financial costs (for example, up to 42% more electricity and 6% of all electricity produced in the USA) ^[54].

Geoengineering (climate engineering, climate intervention) and the potential for worker hazards

Geoengineering is the intentional large-scale human manipulation of the environment and it is often referred to as 'climate intervention' or 'climate-altering' technologies. There are two broad categories of geoengineering: Carbon dioxide removal (removing greenhouse gases from the atmosphere) and Solar radiation management (causing the earth to absorb less solar radiation). Geoengineering includes a number of techniques of varying complexity, risk, and costs. Geoengineering is also highly controversial due to the high degree of uncertainties surrounding its methods and the risks it may pose to the transboundary and global environment, with potentially negative unknown economic and social consequences ^[55]. The extent to which geoengineering would create hazards and risks for workers is still unknown ^[20] .

Research needs

Research is needed to increase the knowledge of climate change effects on workers and improve the options for an effective OSH response. A proper surveillance of diseases, injuries, accidents and occupational hazards to track changes in occupational exposures and to support the development of occupational adaptation strategies by occupational sector is necessary. Outdoor workers are often the first to be exposed to the effects of climate change ^{[12][13] [56]}. Extreme weather events can also put emergency, rescue and clean-up workers in situations involving exposure to hazardous agents as well as physical and psychological risks.
The most vulnerable workers need to be identified through a multidisciplinary research approach (atmospheric science, occupational health, environmental health, epidemiology, geography, medicine, etc.). Research in these areas would help to quantify and to forecast workers at risk by hazard, occupation, and geographic location ^[20]. Assessing the interactions of climate, occupational hazards, and worker vulnerability is an important new area of research. Emerging risks need to be identified with the aim to improve workplace prevention, as regards workers in green jobs, outdoor workers, the agricultural sector, and emergency workers, as well as vulnerable groups (e.g. workers with cardiovascular diseases or lung diseases).
Collection of information on good practices to address the effects of climate change and the mitigation policies (energy transition, chemicals policy, digitalisation, waste policy, etc.) will be necessary. The research needs to address a broad range of risks, risks from biological agents, thermal risks, ergonomic risk factors and psychological risks, as well as safety risks. Investigating the effectiveness of mitigation strategies and hazard controls is essential.
OSH should be integrated in environmental considerations and considered in the impact assessment of climate change mitigation and adaptation policies. Any effectiveness assessment of options should include OSH considerations, i.e. the impact on the safety and health of the workforce concerned. Integrating prevention into design is more efficient than retrofitting OSH.
A better cooperation with public health organisations is needed, e.g. regarding the effects from exposure to biological agents, whether from new or well-known microorganisms. The measures to address the resulting infectious diseases and health needs, should also include OSH considerations, i.e. address the specific exposures of workers and their potential health effects.

Policies and programmes

EU strategies

Climate change policies can be divided into two categories: mitigation and adaptation. Mitigation measures are targeted at reducing or preventing the emissions linked to human activities ^[57]. Adaptation measures aim at adapting to the impacts of climate change ^[58].

In the EU, climate change mitigation fits into the European Green Deal, a package of policy initiatives that aims to be climate neutral by 2050. The package not only includes initiatives covering the climate but also the environment, energy, transport, industry, agriculture and sustainable finance ^[59]. The Just Transition Mechanism (JTM) is a key tool to ensure that the transition towards a climate-neutral economy happens in a fair way, leaving no one behind. It provides targeted support to help mobilise around €55 billion over the period 2021-2027 in the most affected regions, to alleviate the socio-economic impact of the transition, e.g. creating new jobs in the green economy, facilitating employment opportunities in new sectors and those in transition, and offering re-skilling opportunities ^[60].

To address the challenges of climate change, the European Commission has published an EU climate change adaptationstrategy in April 2013, that was updated in 2021 by a new strategy ‘Forging a climate-resilient Europe’^[61]. The strategy is based on the long-term vision that in 2050, the EU will be a climate-resilient society, fully adapted to the unavoidable impacts of climate change. The strategy includes actions to work towards this vision by improving knowledge of climate impacts and adaptation solutions and by stepping up adaptation planning, climate risk assessments and implementing actions. This includes for instance:

• addressing gaps in knowledge by further developing the European climate adaptation platform, Climate-ADAPT and establishing a European climate and health observatory under Climate-ADAPT ^[62];
• promoting long-term economic diversification strategies and policies that enable workers to requalify and move towards green growth sectors, while ensuring a sufficient and highly skilled workforce. This will require an improved understanding of the effects of climate change on workers, working conditions, health and safety, and involving social partners;
• reducing climate related risks by investing in resilient, climate-proof infrastructures, e.g. by updating standards governing the safety and performance of infrastructure in a changing climate ^[61].

Addressing climate change is also integrated in the Strategic Framework on Health and Safety at Work 2021-2027. ‘Anticipating change’ is one of the three key objectives and the framework emphasises the need to consider the impacts of climate change on the workplace as well as to improve preparedness for shock effects with potentially significant repercussions in the area of OSH, such as health crises and climate change events ^[63]. Climate change was identified as one of the key challenges that require OSH policy action in the next years ^[64].

Social dialogue

Both workers’ and employers’ organisations must be involved in the design and implementation of climate change mitigation and adaptation policies. Employers and workers are best placed to identify the challenges and risks that climate change consequences pose to their workplaces and take appropriate action at the workplace, such as ensuring compliance with health and safety standards, and finding practical solutions (e.g. solutions to cope with high temperatures and humidity). They should be involved in the design and implementation of adaptation policies at all levels, with special emphasis on working conditions ^[11] [29].

Through social dialogue and collective bargaining agreements, employers’ and workers’ organisations can develop and implement detailed policies (e.g. for dealing with heat stress at the workplace). Social dialogue is also crucial to the development of national OSH policies, which should be drawn up in consultation with the most representative organisations of employers and workers. The implementing infrastructure for national OSH policies should be established, maintained, progressively developed and periodically reviewed in consultation with those organisations. In addition, social dialogue can help to make climate change governance more labour-friendly by promoting policies that take account of both environmental and labour concerns ^[11] .

National policies

National policies are central to addressing climate change whereby coherent policies are developed, linking economic, environmental, sectoral and enterprise policies with social and labour policies. There are potential synergies for decent work policies and climate change policies. Decent work, green jobs and sustainable development are overlapping objectives ^[65]. Governments can support workplaces in developing prevention strategies by taking initiatives such as ^[66][67]:

• introducing labour standards and technical standards for buildings;
• providing social protection and supporting structural economic shifts towards jobs in economic activities less susceptible to the effects of heat stress;
• setting up early warning systems (e.g. concerning extreme weather conditions);
• promoting awareness-raising campaigns and training programmes for employers and OSH professionals;
• strengthening incentives for employers to improve OSH measures;
• strengthening compliance with requirements of OSH, e.g. through labour inspections.

Risk management

Workplace risk management

Employers are responsible for providing a safe and healthy workplace. Employers in the European Union have a moral and legal responsibility to protect their workforce from safety and health threats. Moreover, preventing occupational illnesses, injuries, and deaths can reduce financial losses related to issues such as absenteeism, reduced productivity, and disruptions to business continuity ^[68]. Health and safety regulations such as the Framework Directive (89/391/EEC) ^[69] oblige employers to assess risks in the workplace, and subsequently take adequate prevention measures. Such assessments should be part of an OSH management system implemented by the employer with participation of the workers.

Occupational risks related to climate change should be addressed as an integral part of the risk management policy of each company, but businesses may not be sufficiently prepared, empowered, educated, concerned, or compelled to protect their employees from the health impacts of climate change ^[15] [65].

Workplace preparedness includes:

1. Devoting resources to hazard recognition;
2. Performing vulnerability assessments to determine which workers are vulnerable to climate change-related hazards (and when, how, and why);
3. Implementing a control strategy with policies, procedures, equipment, and work organisation that eliminates or minimises the impact of these hazards ^[70]. These include also emergency planning and business continuity measures in response to natural disasters such as floods.

Risk control measures

For increased ambient temperature, the focus must be on appropriate prevention of potentially deadly heat illnesses (awareness and education of employers and employees) and  UV radiation, which is carcinogenic ^[20]. Workplaces play a crucial role in the implementation of effective adaptation measures to reduce the impact of heat stress. By developing a heat plan tailored to the workplace before hot weather arrives, employers can immediately roll out appropriate measures during periods of extreme ambient temperatures. The website Heat-shield.eu proposes such a plan.

Workplace measures can be divided into technical, organisational and individual measures.

Examples of measures include ^{[17][66] ​​​​​[71][72]}:

Technical measures

• adapting work processes e.g. reducing heat release;
• isolating machinery/processes that generate heat (or separate them from workers);
• providing sustainable cooling systems in indoor workplaces;
• installing canopies to create shade at outdoor work areas;
• providing vehicles equipped with air-conditioned closed cabins (e.g. on tractors, trucks, loaders, cranes);
• providing lifting and handling aids to reduce handling loads;
• setting up water stations in multiple locations, easy accessible for all workers;
• providing dedicated cooling areas (indoor areas equipped with air conditioning);

Organisational measures

• adapting work schedules to reduce exposure to high ambient temperatures;
• planning of work tasks (e.g. planning physically demanding work tasks when it is cooler (early morning/late evening);
• reviewing working arrangements (e.g. temperature-dependent break times, guidelines for working from home);
• implementing a buddy system (pairing of workers to take care of each other and take immediate action in case of early warning signs of heat stress);
• providing cool drinking water;
• providing sufficient breaks in a cool(ed) environment;
• promoting education and training.

Individual measures

• introducing smart monitoring of workers’ conditions, such as hydration (water consumption) and body heat through the use of smart PPE;
• individual coaching e.g. the Heat-Shield alert system ^[73] provides personalised forecasts for workers, advice on hydration and how to minimise heat load based on individual characteristics of the worker, location, the type of clothing worn, the level of physical activity and the work environment.
• providing suitable clothing for hot weather/ UV-radiation: lightweight clothing in light colours (uv standard 801 ^[74] or EN 13758 ^[75]; wide-brimmed hat/helmet, sun barrier cream
• providing PPE with cooling function (e.g. cooling vest ^[76], cooling cap).

The use of PPE in extreme heat conditions is particularly challenging, especially for outdoor workers ^[77]. PPE adds to the effort and stress of the job. The PPE itself can contribute to heat stress. It has been observed that farm and forestry workers remove PPE in excessively hot conditions. When selecting the appropriate PPE, particular attention should be paid to the case where workers must wear PPE in a hot environment. Some types of PPE are more suitable than others for use in warm temperatures (e.g. the use of a powered breathing apparatus instead of filtering respirators (masks)). Additional organisational measures may also be needed, such as providing more frequent breaks for recovery when using respiratory protection ^[77].

Guidance

A number of good practice guides exist on how workplaces can manage heat stress and/or exposure to natural UV-radiation. Examples include:

• Guidance and infographics on the Heat-shield website ^[32];
• Topic Heat stress on the website of the Health and Safety Executive (HSE) ^[78] ; 
• The website Workklimate (in Italian) ^[79] with information on the project set up by INAIL to gather knowledge on the effects of ambient heat on workers;
• Topic Heat stress on the website from INRS (in French) ^[80];
• Guidance for specific sectors such as a guide developed for the paper industry (in German) ^[81] and a leaflet for the agricultural sector (in French) ^[82].
• Leaflets and videos with practical tips:
  - Napo in… Heatstress ^[83];
  - Nine tips to reduce heat stress in the workplace  ^[84] ;
  - video Arbeiten unter der Sonne (working in the sun) ^[85] developed in the framework of the GENESIS-UV project in Germany. The project collects data form exposure measurements of outdoor workers to solar UV radiation ^[86].
  - video Consejos preventivos: Trabajar con calor (Prevention tips: heat stress at work) ^[87].

Conclusions

The progression of climate change implicates new and intensified occupational hazards which prompt the reconsideration of risk levels of certain occupations (e.g. those requiring outdoor work, green jobs). The risks related to climate change, risks related to biological, chemical and physical agents as well as risks to mental health, need to be addressed properly in workplace risk assessments. Knowledge should focus on how climate change, affecting several factors, modulates multiple and interacting occupational exposures. Climate change could exacerbate existing safety and health risks and create new ones. Emerging vector-borne, waterborne diseases and zoonoses, such as Lyme Disease and leptospirosis, are likely to impact OSH. The introduction of new pests and pathogens could change the types and amounts of pesticides, e.g. antimicrobial pesticides, used by agricultural workers and others.  Exposure to chemicals may further be exacerbated due to increased inhalation and absorption and non-use or incorrect use of PPE under heat conditions. The exposure to UV radiation, a recognised cancer risk factor (for the skin) is increasing and so is exposure to heat at work, the cause of the potentially deadly heat illnesses. Because of the increasing frequency, duration and severity of extreme weather events and natural disasters, rescue, emergency and recovery workers are faced with increased health and safety risks, e.g. falls, burns, smoke inhalation, musculoskeletal disorders, and mental distress. Different exposures during emergency, rescue, first response and clean-up activities must be monitored (for example to asbestos, silica dusts, or biological agents), and the mental health effects of regularly working long hours should be assessed.

The variability of climate change has also added a layer of uncertainty on occupational risk assessments. Climate change varies with different geographical regions. Current research tends to focus on heat due to global warming. However, more studies are needed on the occupational impacts associated with other facets of climate change, such as the rising sea level, more frequent floods, more intense storms, and on the measures that are taken to adapt to climate change (e.g. new building techniques, more green jobs, increased recycling in the context of a circular economy). Prevention and economic investments are needed because they may give benefits for occupational safety and health in times of global climate change. Indeed, climate change impacts on work, influencing all economic sectors, even those previously thought to be insensitive to climate. A wider, multidisciplinary approach (including climatology, medicine, epidemiology, etc.), and more research are needed to tackle the upcoming occupational safety and health problems.