Climate and health expert Madeleine Thomson warns of heart disease, kidney failure, and pregnancy complications linked to workplace heat exposure as global temperatures rise
When most people think about the dangers of working in extreme heat, heat stroke comes to mind. But according to Dr. Madeleine Thomson, Head of Climate Impacts & Adaptation at Wellcome, the real threat to workers runs much deeper—and we’re dangerously unprepared for what’s coming.
Responding to a new joint report from the World Health Organisation (WHO) and World Meteorological Organisation (WMO) on climate change-driven heat stress affecting workers, Thomson delivered a stark warning that should concern employers, policymakers, and workers worldwide.
“The health and wellbeing threat to workers from extreme heat goes far beyond heat stress,” Thomson said. “Rising temperatures are linked to heart disease, kidney failure, pregnancy complications, and poor mental health. And these health impacts affect economies and healthcare systems, and yet we remain dangerously unprepared.”
The Expert Behind the Warning
Thomson’s alarm bells carry weight. With over 25 years of research experience focused on climate-sensitive health interventions, she has witnessed firsthand how rising temperatures reshape public health landscapes across the globe. Her career has taken her from field research in Africa to directing the WHO Collaborating Centre on Malaria Early Warning Systems at Columbia University’s International Research Institute for Climate and Society, where she served as a Senior Research Scientist.
Now at Wellcome, one of the world’s leading health research foundations, Thomson leads work on climate adaptation strategies—making her uniquely positioned to understand how climate change cascades through human health systems in ways most people never consider.
Beyond the Obvious: Heat’s Hidden Health Toll
While heat stroke makes headlines, Thomson points to a constellation of serious health conditions that develop more insidiously in workers exposed to prolonged high temperatures:
Cardiovascular Disease: Extreme heat forces the heart to work harder to cool the body, increasing cardiovascular strain. For workers with existing heart conditions or those performing physically demanding jobs, this added stress can trigger heart attacks and other cardiac events.
Kidney Failure: Repeated exposure to heat, especially when combined with dehydration, can cause chronic kidney disease. This is particularly concerning for agricultural workers, construction crews, and others who spend long hours in hot environments with inadequate access to water.
Pregnancy Complications: Pregnant workers face elevated risks, as their bodies already struggle with temperature regulation. Heat exposure has been linked to preterm birth, low birth weight, and pregnancy loss—complications that affect not just individual families but healthcare systems and workforces.
Mental Health Impacts: The psychological toll of working in extreme heat is often overlooked. Heat exposure has been associated with increased rates of anxiety, depression, and even suicide, compounding the physical health challenges workers face.
The Economic Reality No One Wants to Face
Thomson emphasises that these health impacts ripple far beyond individual suffering. “These health impacts affect economies and healthcare systems,” she notes, highlighting a reality that businesses and governments are only beginning to reckon with.
When workers develop chronic conditions from heat exposure, productivity declines, healthcare costs surge, and workforce participation drops. The economic burden extends across multiple sectors—from increased insurance claims and workers’ compensation costs to lost labour hours and reduced economic output.
Yet despite these mounting costs, Thomson’s assessment is blunt: “We remain dangerously unprepared.”
What Must Happen Now
Fortunately, Thomson doesn’t just sound the alarm—she offers a roadmap. Her call to action targets both the root cause and immediate adaptations:
Cut Greenhouse Gas Emissions: “Governments and employers must act now by cutting greenhouse gas emissions,” Thomson insists. Without addressing the underlying driver of rising temperatures, adaptation measures will only go so far.
Implement Workplace Protections: Thomson outlines practical interventions that employers can implement immediately:
- Adapting work schedules to avoid the hottest parts of the day
- Ensuring regular access to shaded areas
- Providing consistent rehydration opportunities
- Establishing clear protocols for monitoring worker wellbeing in hot conditions
Act With Urgency: Perhaps most importantly, Thomson underscores the time-sensitive nature of this crisis. “The longer we delay action, the greater the threat to lives and livelihoods.”
The Research-Policy Connection
Thomson’s response to the WHO-WMO report also highlights how her work at Wellcome bridges cutting-edge research with urgent policy needs. “Innovative research that brings together climate science and health is increasingly revealing how significantly climate change affects our health and wellbeing, and provides the critical evidence that underpins this important new WHO-WMO report,” she explained.
This integration of climate science and health research represents Thomson’s career-long commitment. From her early work developing malaria early warning systems to her current focus on climate adaptation, she has consistently championed the use of robust scientific evidence to inform health interventions.
A Crisis Unfolding in Real Time
The timing of Thomson’s statement couldn’t be more critical. As global temperatures continue to break records and extreme heat events become more frequent and severe, the health threats to workers intensify. The 2024 summer saw record-breaking heat across Europe and other regions, offering a preview of the conditions workers will increasingly face without decisive action.
For Thomson, the path forward is clear but requires immediate commitment from multiple stakeholders. Employers must prioritise worker safety over short-term productivity gains. Governments must enact and enforce protective regulations whilst pursuing aggressive emissions reductions. And healthcare systems must prepare for the surge in heat-related conditions that will strain resources in the coming years.
The Bottom Line
Dr. Madeleine Thomson’s response to the WHO-WMO report serves as both a wake-up call and a practical guide. The hidden health crisis facing workers in extreme heat extends far beyond what most people understand, touching cardiovascular health, kidney function, pregnancy outcomes, and mental wellbeing.
But this isn’t a problem without solutions. As Thomson makes clear, we have the knowledge and tools to protect workers—what we need now is the will to act. The question is whether governments and employers will heed her warning before the toll on lives, livelihoods, and economies becomes even more severe.
In Thomson’s own words: the threat is real, the evidence is clear, and the time to act is now.