Climate Change, Extreme Heat, and Workplace Safety
- Dr Catia Nicodemo
- 55 minutes ago
- 6 min read
Climate change is often framed as a distant or abstract threat, discussed in terms of global temperature targets, future decades, or environmental tipping points. Yet for millions of people, its consequences are already being felt in ordinary, everyday settings. One of the most immediate and overlooked impacts of climate change is its effect on health and safety at work. As temperatures rise and heatwaves become more frequent in the United Kingdom, the risk of workplace accidents, injuries, and even deaths is increasing. This is not simply a matter of discomfort or reduced productivity; it is a growing public health issue that intersects directly with labour rights, occupational safety, and social inequality.
The human body is not designed to function optimally under sustained heat stress. When temperatures rise, the body must divert energy toward cooling itself through sweating and increased blood flow to the skin. This process places strain on the cardiovascular system and accelerates dehydration, particularly during physical activity. In a work context, this physiological stress has clear consequences. Fatigue sets in more quickly, concentration becomes harder to maintain, reaction times slow, and decision-making deteriorates. Tasks that would normally be routine become more error-prone, and the margin for safety narrows.
As climate change pushes temperatures higher, these effects are no longer limited to exceptional heatwaves but are becoming part of the normal working environment. Research consistently shows that workplace injury rates rise on hotter days. Even relatively small increases in ambient temperature are associated with measurable increases in accidents, particularly in physically demanding jobs or roles that require sustained attention. While the increase in risk per degree Celsius may appear modest, the cumulative impact across large populations and repeated hot periods is substantial. When applied to millions of workers over the course of a summer, small percentage increases translate into thousands of additional injuries.
The risk is further amplified during prolonged heat events. Heatwaves do not allow the body adequate time to recover, especially when nights remain warm. Sleep quality declines, compounding fatigue and impairing cognitive function the following day. Over successive days, the likelihood of mistakes and incidents rises steadily. This dynamic is particularly concerning in sectors where a single error can have severe consequences, such as construction, transport, manufacturing, and utilities.
Certain groups of workers are especially vulnerable to these conditions. Outdoor workers face direct exposure to solar radiation and often perform heavy physical labour. Construction workers, agricultural labourers, road crews, and delivery workers frequently lack sufficient shade or cooled rest spaces. Indoor workers are not immune; factories, warehouses, commercial kitchens, and industrial facilities can become dangerously hot, particularly where ventilation is inadequate or machinery generates additional heat. In such environments, temperatures may exceed those outdoors, while workers have little opportunity to escape the heat.
The use of personal protective equipment, while essential for safety, can worsen heat stress. Protective clothing and respirators restrict airflow and reduce the body’s ability to cool itself. Workers wearing such equipment may experience dangerous levels of heat strain even at temperatures that might otherwise be considered moderate. This creates a difficult trade-off between protection from immediate hazards and protection from heat-related illness, one that becomes more acute as the climate warms.
Beyond accidents and injuries, extreme heat also contributes to increased mortality. Heatwaves are associated with spikes in deaths from cardiovascular disease, respiratory illness, kidney failure, and other conditions. For workers, especially those engaged in strenuous activity, the combination of physical exertion and heat exposure can push already stressed bodies beyond safe limits. Heat exhaustion and heat stroke can develop rapidly and can be fatal without prompt treatment. These risks are higher for older workers, people with chronic health conditions, pregnant workers, and those taking medications that affect hydration or temperature regulation.
In the UK, heat-related deaths have historically been underestimated, partly because heat is often recorded as a contributing factor rather than a primary cause. However, public health data increasingly show clear correlations between extreme heat events and increased mortality. Climate change is making such events more frequent, longer-lasting, and more intense. What was once considered exceptional weather is becoming a regular feature of British summers, with profound implications for health and safety.
The policy framework in the UK recognises, at least in principle, that temperature is a workplace hazard. Employers have a legal duty under health and safety law to assess risks and protect workers from harm, including risks associated with heat. The Health and Safety Executive provides guidance on managing thermal comfort and heat stress, emphasising the need for risk assessments, adequate hydration, rest breaks, and appropriate ventilation. Unlike cold environments, however, there is no legally defined maximum working temperature. Responsibility is placed on employers to judge what is “reasonable” in a given context.
At the same time, public health policy has begun to adapt to the realities of climate change. The UK government’s Adverse Weather and Health Plan, which incorporates heat-health alerts, acknowledges extreme heat as a serious risk to population health. These alerts are designed to prompt coordinated action across health and social care services, local authorities, and community organisations. Yet the translation of these warnings into concrete workplace protections remains inconsistent. Many workers continue to rely on employer goodwill rather than enforceable standards.
As climate risks intensify, this reliance on voluntary measures is increasingly questioned. There is a growing argument that workplaces, particularly in high-risk sectors and regions, should be required to implement formal heat action plans. Such plans would move responses from reactive to preventative, ensuring that protections are in place before temperatures become dangerous. Mandatory planning would also help address inequalities, as workers in insecure or low-paid jobs are often least able to advocate for themselves or refuse unsafe work.
A robust heat action plan would not be complex or burdensome. It would involve identifying roles most exposed to heat, adjusting working hours during hot periods, increasing the frequency of breaks, ensuring access to shade and drinking water, and training staff to recognise the signs of heat-related illness. Clear procedures for modifying or stopping work during extreme conditions would provide both workers and managers with certainty and protection. Importantly, such plans would normalise the idea that heat is a legitimate occupational hazard, deserving the same attention as chemical exposure or working at height.
Climate adaptation is often discussed in terms of infrastructure, such as flood defences or energy systems, but it is equally a workplace issue. Many workplaces in the UK were designed for a cooler climate and are poorly suited to higher temperatures. Retrofitting buildings for better ventilation, shading, and cooling is a long-term investment that can improve safety, productivity, and wellbeing. At the same time, integrating climate data into occupational risk assessments can help organisations anticipate and prepare for future conditions rather than responding after harm has occurred.
There is also a broader social dimension to consider. The impacts of heat are not evenly distributed across society. Those most exposed at work are often those with fewer resources, less job security, and greater baseline health risks. Climate change therefore risks deepening existing inequalities unless protective measures are explicitly designed to reach those most at risk. Viewing heat protection as a matter of social justice, as well as health and safety, strengthens the case for stronger regulation and enforcement.
Visualising the relationship between temperature and workplace risk can help make these issues more tangible. Even conservative estimates show that as temperatures rise by just a few degrees, the relative risk of injury increases noticeably. When this increased risk is multiplied across entire workforces and repeated over many hot days, the scale of the problem becomes clear. Climate change does not need to produce extreme, unprecedented temperatures to cause harm; incremental warming alone is sufficient to increase accidents and deaths if no action is taken.
Ultimately, the connection between climate change, health, and workplace safety highlights the need for joined-up thinking. Environmental policy, public health, and labour regulation cannot operate in isolation. Protecting workers in a warming climate requires recognising heat as a systemic risk and responding with coordinated, enforceable measures. The evidence is clear, the tools exist, and the costs of inaction are rising.
Climate change is already reshaping the conditions under which people live and work in the UK. Rising temperatures are increasing workplace accidents, worsening health outcomes, and contributing to preventable deaths. Addressing these risks is not only possible but necessary. By strengthening heat protections, particularly for those most exposed, the UK can reduce harm, save lives, and build a more resilient workforce in the face of a warming future.
