The Worker Heat Crisis: Why Climate Expert Madeleine Thomson Says We’re ‘Dangerously Unprepared’
Wellcome’s Head of Climate Impacts & Adaptation responds to new WHO-WMO report with urgent call for workplace protections and emissions cuts
“We remain dangerously unprepared.”
It’s not a phrase Dr. Madeleine Thomson uses lightly. And when someone with more than 25 years of experience studying climate-sensitive health threats delivers such a stark assessment, the world should listen.
Thomson, Head of Climate Impacts & Adaptation at the Wellcome Trust, recently responded to a landmark joint report from the World Health Organization (WHO) and World Meteorological Organization (WMO) examining the health impact of climate change-driven heat stress on workers. Her reaction was unequivocal: we’re facing a worker health crisis that extends far beyond what most people understand, and our current preparations fall dangerously short of what’s needed.
From Field Entomologist to Climate Health Leader
Thomson’s journey to becoming one of the world’s leading voices on climate and health began in an unexpected place—studying insects in the field. Originally trained as a field entomologist, she spent her early career conducting operational research to support large-scale health interventions in Africa, including work on The
Gambia’s national impregnated bednet programme.
That hands-on experience with vector-borne diseases gave Thomson a unique perspective: she saw firsthand how environmental factors—temperature, rainfall, climate patterns—directly influenced disease transmission and public health outcomes.
“I spent much of my early career undertaking operational research to support large-scale health interventions in Africa,” Thomson has said, reflecting on work that would shape her understanding of the intricate connections between climate and human health.
This foundation led her to Columbia University’s International Research Institute for Climate and Society, where she served as a Senior Research Scientist and directed the WHO Collaborating Centre on Early Warning Systems for Malaria and Other Climate-Sensitive Diseases. There, she pioneered methodologies for integrating climate data with health information—work that became increasingly urgent as global temperatures began their steady climb.
A Career Built on Connection
What distinguishes Thomson’s approach is her ability to bridge multiple disciplines. She holds degrees from the University of Sheffield (BSc), Imperial College London (MSc), and the University of Liverpool (PhD), but it’s her practical experience connecting climate science with public health that has defined her career.
At Columbia, Thomson didn’t just study climate-sensitive diseases—she developed tools that health officials could actually use. Her work on malaria early warning systems, for instance, helped communities prepare for disease outbreaks before they spiraled out of control. She applied similar thinking to meningococcal meningitis in Africa’s Sahel region and later to emerging threats like Zika virus.
“We look at how knowledge and information about the climate can improve health decision-making, particularly in developing countries,” Thomson explained in a 2016 interview, articulating a mission that has remained consistent throughout her career.
Now, as Head of Climate Impacts & Adaptation at Wellcome, one of the world’s most influential health research foundations, Thomson oversees initiatives that span from infectious disease control to the health impacts of extreme weather events and nutrition challenges in low- and middle-income countries.
Why “Dangerously Unprepared” Matters
When Thomson says we’re “dangerously unprepared” for the worker heat crisis, she’s drawing on decades of watching health systems struggle to adapt to changing climate realities. Her warning about workplace heat stress isn’t speculation—it’s pattern recognition from someone who has studied how environmental changes cascade through human populations.
In her response to the WHO-WMO report, Thomson emphasized that the threat extends far beyond the heat stroke that typically dominates public discussion: “The health and wellbeing threat to workers from extreme heat goes far beyond heat stress—rising temperatures are linked to heart disease, kidney failure, pregnancy complications, and poor mental health.”
This comprehensive view reflects Thomson’s career-long insistence on looking at the full picture. Just as she recognized that malaria wasn’t just about mosquitoes but about climate patterns, early warning systems, and community preparedness, she now sees worker heat stress as a complex challenge requiring multiple interventions.
The Economic Dimension
Thomson also brings a clear-eyed understanding of how health impacts ripple through economic systems—a perspective honed through years of working with governments and international organizations trying to protect both people and economies.
“These health impacts affect economies and healthcare systems,” she noted in her statement, pointing to a reality that policymakers can’t ignore. When workers develop chronic conditions from heat exposure, the costs compound: lost productivity, increased healthcare spending, reduced workforce participation, and strained social safety nets.
This economic framing isn’t incidental—it’s strategic. Thomson understands that protecting worker health isn’t just a moral imperative; it’s an economic necessity that governments and employers must address.
A Roadmap Born from Experience
Thomson’s call to action reflects lessons learned across her career working in some of the world’s most climate-vulnerable regions:
Immediate Workplace Protections: Drawing on her experience developing practical health interventions, Thomson outlines actionable steps employers can take now—adapting work schedules, providing regular access to shaded areas, and ensuring consistent rehydration opportunities.
Long-term Emissions Reductions: But Thomson knows that adaptation alone won’t suffice. “Governments and employers must act now by cutting greenhouse gas emissions,” she insists, recognizing that without addressing root causes, the problem will only intensify.
The Urgency Factor: Perhaps most tellingly, Thomson emphasizes timing: “The longer we delay action, the greater the threat to lives and livelihoods.” It’s a message she’s delivered before, watching as delayed action on climate-sensitive diseases led to preventable suffering.
Bridging Research and Policy
One aspect of Thomson’s response particularly reflects her current role at Wellcome: the connection between research and policy action. She highlighted how “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.”
This isn’t abstract advocacy. At Wellcome, Thomson has helped fund and guide research teams developing digital tools to predict and respond to climate-sensitive health threats. It’s work that builds directly on her years directing the WHO Collaborating Centre, where she saw how good data and smart tools could save lives.
Thomson also serves as a Visiting Professor at Lancaster University Medical School, ensuring that the next generation of health professionals understands the climate-health connection—another investment in long-term preparedness.
Learning from Vector-Borne Diseases
Thomson’s background in infectious disease research offers valuable lessons for addressing worker heat stress. When she worked on malaria early warning systems, the challenge wasn’t just predicting where mosquitoes would breed—it was building systems that health officials could use to mobilize resources and target interventions effectively.
The same principle applies to protecting workers from heat. It’s not enough to know that heat is dangerous; we need systems that identify at-risk workers, trigger protective measures, and ensure accountability.
In a 2016 interview about Zika virus, Thomson noted: “We have to expect more of this type of emergence: new diseases that were historically isolated (and therefore didn’t have a big impact) which can spread very rapidly and have a huge impact on a large community. Zika is not the last. There’ll be others, but predicting exactly what, where and when is really difficult. Instead we need to prepare ourselves t
o be able to respond rapidly to a broad range of possible threats.”
Replace “diseases” with “health crises” and the same wisdom applies to worker heat stress. We can’t predict every heat wave, but we can build systems and protections that respond effectively when they occur.
The Credibility Factor
What makes Thomson’s “dangerously unprepared” assessment so compelling is that it comes from someone who has spent her career preparing communities for health threats. She has developed early warning systems, directed WHO collaborating centres, advised governments, and led research initiatives across multiple continents.
She has also been consistently ahead of the curve. Her work on climate-sensitive infectious diseases positioned her to understand emerging threats like Zika before they exploded into international headlines. Her focus on climate adaptation came years before it became a mainstream concern.
When someone with that track record says we’re dangerously unprepared, it’s worth taking seriously.
What Comes Next
Thomson’s response to the WHO-WMO report serves as both warning and roadmap. The worker heat crisis is here, the evidence is clear, and the solutions exist. What’s missing is the will to implement them at the scale and speed required.
For Thomson, this is familiar territory. Throughout her career, she has worked to translate scientific evidence into action, whether developing malaria early warning systems in Africa or advising on climate adaptation strategies for vulnerable populations worldwide.
The worker heat stress crisis is just the latest challenge requiring that same approach: robust evidence, practical interventions, and urgent action from governments and employers alike.
As Thomson makes clear, we have the knowledge to protect workers. The question is whether we’ll act before the “dangerously unprepared” assessment becomes a tragic epitaph for preventable suffering.
