The implications for a warmer climate are many, but perhaps one of the most frequently overlooked is what it could mean for worker safety and productivity in certain sectors of the global economy.

Outdoor laborers and some indoor workers are disproportionately impacted by the changing climate in a variety of ways. A 2009 study published in the Journal of Occupational and Environmental Hygiene categorized seven “climate-related occupational hazards”: extreme weather events, increased temperature, air pollution, ultraviolet radiation exposure, vector-borne illnesses, and changes in the built environment and industrial facilities. Updated and continued research published in 2016 added three more categories: mental health effects, economic losses from reduced labor due to heat, and impacts associated with geoengineering.

Overall, some 1 billion people are currently employed in the global agricultural sector, making up one-third of all workers, and the construction sector is expected to expand significantly in coming decades, especially in sub-Saharan Africa and Asia. Many of these workers will face harsher conditions and difficult choices between reducing workloads (and therefore incomes) or higher health risks, like heat stroke, heart conditions, and infectious diseases. Emergency responders will also face higher risks of injury and death, thanks to more frequent and damaging natural disasters.

Health vs. Income?

Higher temperatures are among the most widely recognized impacts of climate change, but the connection to how such changes might affect the health and productivity of outdoor workers is not always made.

A research program based in New Zealand that includes work from six universities and input from scientists from 21 countries called HOTHAPS (high occupational temperature health and productivity suppression) is looking at the extent to which workers are impacted by heat exposure and how climate change may increase the severity of those impacts.

In field studies in 11 countries the program found there is a reduction of work capacity and economic productivity when workers need to take breaks or pare back their level of physical effort, especially if there is no way to cool off onsite. Outdoor laborers are disproportionately exposed to the effects of higher temperatures, such as heat strain, heat stroke, exhaustion, and dehydration, and the physical nature of their work causes them to create even more heat internally.

By the 2080s, parts of Southeast Asia, Latin America, eastern sub-Saharan Africa, and the Caribbean could see productivity declines between 11 and 27 percent because of higher temperatures according to one estimate published in Archives of Environmental and Occupational Health.

A study in the Journal of Occupational and Environmental Hygiene explains that taking more breaks and exerting less to avoid heat problems may not be an option for some workers, especially outdoor laborers who are paid at a piece rate, payment for units produced instead of hours worked. Many will face tradeoffs between their health and income as a result.

In what might be a preview of conditions to come, construction workers in Qatar have faced problems as they race to complete nine new stadiums and surrounding facilities before the 2022 FIFA World Cup in temperatures as high as 122 degrees Fahrenheit. Amnesty International and other advocacy groups have raised concerns for years over the treatment of construction workers in Qatar, who mostly hail from Nepal, India, and Bangladesh. A Guardian investigation in 2013 found that Nepalese laborers were dying at a rate of almost one a day, many from heart problems.

After a worker died in May 2016 from a heart attack and many others complained of dehydration and heat exhaustion, scientists at Qatar University designed solar-powered cooling hard hats that can reduce skin temperature by up to 50 degrees Fahrenheit by blowing air onto the workers’ faces and operate for up to four hours at a time.

How many workers have access to the technology, however, remains unclear, especially since so many migrant workers face a litany of other abuses, such as small and dirty living spaces, delayed and falsely promised salaries, and bans from leaving their construction sites or the country. For some, the choice between health and income isn’t even one they can exercise. According to an Amnesty International report in 2013, many migrant workers are effectively “trapped” by employers who refuse to grant promised visas or even confiscate passports.

On the Frontlines

Increases in temperatures and frequency of natural disasters also pose threats to medical and emergency response teams.

In the United States alone there are more than 100,000 wildfires each year. Higher temperatures will create the conditions for more frequent and intense wildfires, according to a report by Peter Within, an associate professor of sociology at the University of Virginia’s College at Wise. Though many wildfires are manmade, the changing climate helps fires spread. Additionally, fire seasons are expected to “start earlier, end later, and burn hotter.” Fires are increasing in the western United States and also in high-latitude areas such as Alaska, Canada, and Siberia. The fire season in Alaska has already increased from less than 45 days in 2000 to about five months today, according to Within.

Heat exhaustion directly affects firefighters, and there are other physical dangers from burnovers – when a wildfire overtakes firefighters and equipment – and tree hazards. The 2014 Intergovernmental Panel on Climate Change assessment report, which synthesized the best available scientific data from around the world, found there is a “greater risk of injury, disease, and death due to more intense heat waves and fires.”

Climate change is also increasing the frequency and severity of hurricanes, flooding, drought, and other natural disasters. There are “dramatic surges in demand” during and after these extreme weather events for workers in the emergency response and medical aid sectors, and in cleanup and restoration, according to a 2010 study published in Global Health Action. People in these roles are expected to “work harder, for extended periods, in difficult (often dangerous) circumstances, and with limited resources.” They may also be exposed to new and different kinds of health threats, like diarrheal disease from overloaded sewage systems, as was seen in responders across five different states after Hurricane Katrina.

There are also concerns about the long-term wellbeing of emergency workers. Continuous treatment of victims of intense natural disasters can cause physical and emotional fatigue in the responders, akin to the kind of “climate trauma” being observed by psychologists among farmers and other communities.

A Cascading Challenge

Developing countries will bear the brunt of changes to worker safety and productivity, Bennett and McMichael found in Global Health Action. The agricultural sector – the largest employer of outdoor workers – accounts for a much larger percentage of the labor force and economy in developing countries, and it is also harder for those economies to adapt to climate change generally given the relative lack of resources.

But the climate impacts on occupational safety and productivity will ultimately affect “all economic levels,” the report found. Declines in productivity will ripple across the global economy, affecting investors and consumer prices.

As well, even if developed countries are better equipped to respond to new shocks and stresses, the higher burden on first responders will be felt by the broader community. “The removal of emergency response personnel from the workforce in emergency situations may have strong detrimental effects on the health and wellbeing of all residents and also increase the demand on public health sectors at a critical time,” according to Bennett and McMichael.

Meanwhile, increased temperatures and changes in rainfall and humidity are expanding the range of mosquitoes, ticks, and other species that act as vectors of disease. As a result, many outdoor workers in regions where such diseases have not historically been a problem are now at higher risk of contracting malaria, dengue, yellow fever, and Lyme disease, which already cause more than a million deaths a year globally.