Fewer than 1 percent of studies used a One Health framework linking human, animal, and ecosystem health.
Over nearly three decades and across almost 21,000 scientific studies, a picture has emerged that is as sobering as it is clarifying: climate change is not merely an environmental story but a profound reorganization of human health itself. Diseases once confined by geography are crossing new frontiers, mental suffering is deepening alongside physical illness, and the systems meant to protect the most vulnerable are fraying under compounding pressures. The research does not simply document a crisis — it reveals how fragmented our response remains, and how urgently the boundaries between human, animal, and environmental health must be dissolved.
- Mosquitoes and ticks are colonizing regions where they were once unknown, carrying dengue, malaria, Zika, and Chikungunya into communities with no immunity and no warning infrastructure.
- A parallel mental health emergency — marked by anxiety, depression, trauma, and the grief of ecological loss known as solastalgia — is striking hardest at women, children, Indigenous peoples, and coastal communities already stretched to their limits.
- Fewer than one percent of the nearly 6,000 studies on vector-borne disease and health systems applied a One Health framework, exposing a dangerous silo effect where public health, veterinary science, ecology, and climate planning rarely speak to one another.
- Low- and middle-income countries, facing the heaviest disease burden, often lack the early-warning systems, trained workers, and climate-integrated health strategies needed to respond before crises overwhelm them.
- Researchers are calling for a fundamental reorientation — cross-disciplinary partnerships, embedded One Health principles in national and global agendas, and a new generation of professionals trained to work at the intersection of climate, ecosystems, and human wellbeing.
A warming planet is redrawing the map of human disease in real time. Mosquitoes are establishing themselves in cooler regions. Ticks are ascending mountain ranges. Floods are poisoning water supplies. And hospitals, already overstretched, are buckling under heatwaves that arrive with increasing ferocity. A systematic review of nearly 21,000 studies spanning three decades captures this transformation in granular detail.
In the early 1990s, climate-health research focused on a narrow set of diseases — dengue, cholera, malaria, yellow fever. Today the list has expanded to include Ebola, Chagas disease, Zika, Chikungunya, schistosomiasis, and COVID-19. Rising temperatures and shifting rainfall are redrawing the boundaries of where disease-carrying insects can survive. Urban sprawl is pushing people closer to wildlife reservoirs of infection. Seasonal disruptions are catching unprepared health systems off guard.
But physical illness is only part of the story. The research documents a surging mental health crisis running in parallel — communities enduring repeated disasters and watching ecosystems collapse are reporting rising rates of anxiety, depression, and post-traumatic stress. Researchers have even named the specific grief of ecological loss: solastalgia. The burden falls hardest on women, children, older adults, Indigenous populations, smallholder farmers, and coastal residents — those with the fewest resources to adapt or escape.
What the review reveals most starkly is not just the scale of the threat but the inadequacy of the response. Fewer than one percent of studies on vector-borne disease and health systems used a One Health framework — the principle that human, animal, and environmental health are inseparable. Public health specialists, veterinarians, ecologists, and climate scientists continue to work in isolation from one another, producing a patchwork of responses that miss the deeper connections driving disease emergence.
The researchers call for a fundamental reorientation: One Health principles embedded in global and national climate agendas, cross-disciplinary partnerships linking epidemiology with climate modeling and ecology, early-warning systems that anticipate where diseases will move next, and a new generation of health professionals trained to work across these intersections. The knowledge of what must be done exists. What remains in question is whether institutions can reorganize themselves quickly enough to act.
A warming planet is remaking the map of human disease. Mosquitoes are moving into cooler regions where they've never thrived before. Ticks are climbing higher up mountains. Floods are contaminating water supplies. Heatwaves are collapsing the capacity of hospitals already stretched thin. And underneath it all, a quieter crisis is unfolding: people are becoming anxious, depressed, traumatized by the knowledge that the world they knew is disappearing.
A systematic review of nearly 21,000 scientific studies published over the past three decades tells this story in granular detail. Researchers analyzing two decades of climate-and-health research found that the scope of threats has expanded dramatically. In the early 1990s, the focus was narrow: dengue, cholera, malaria, yellow fever. Today the list includes schistosomiasis, leishmaniasis, Ebola, rabies, Chagas disease, Zika, Chikungunya, and COVID-19. The pattern is clear: as the climate shifts, so does the geography of disease. Rising temperatures and changing rainfall patterns are altering where disease-carrying insects can survive. Urban sprawl is bringing people closer to wildlife reservoirs of infection. Seasonal shifts are throwing off the timing of disease transmission in ways that catch unprepared health systems off guard.
But the physical threats are only part of the picture. The research documents a parallel mental health emergency. Communities facing repeated disasters, watching ecosystems collapse, experiencing slow environmental degradation are reporting surging rates of anxiety, depression, and post-traumatic stress. There's even a name for the specific dread of ecological loss: solastalgia. The people bearing this burden most heavily are women, children, older adults, Indigenous populations, smallholder farmers, and residents of coastal and low-lying regions—those with the least capacity to adapt and the fewest resources to escape.
What's striking about this research is not just what it documents but what it reveals about how we're responding to it. Of the nearly 6,000 studies that examined vector-borne diseases, health systems, or disease surveillance, fewer than 1 percent approached the problem using what researchers call a One Health framework—the idea that human health, animal health, and environmental health are inseparable and must be addressed together. Instead, the field remains fragmented. Public health specialists work in isolation from veterinarians. Epidemiologists don't talk to ecologists. Climate scientists operate separately from health planners. The result is a patchwork of responses that miss the deeper connections.
The gaps in preparedness are equally stark. Investment in integrated disease monitoring, citizen-science participation, and climate-linked health system planning accounts for less than 1 percent of the research literature. Low- and middle-income countries, where the health burden will be heaviest, often lack the basic infrastructure to respond: early-warning systems for heatwaves and floods, trained frontline workers, climate risk management embedded in national health strategies. The researchers call for a fundamental reorientation. They want One Health principles embedded in global and national climate agendas. They want cross-disciplinary partnerships linking epidemiological data with climate modeling and ecological research. They want early-warning systems and vector-control programs that anticipate where diseases will move next. They want a new generation of health professionals trained to work at the intersection of climate, ecosystems, and human wellbeing.
The challenge is not a lack of knowledge about what needs to happen. It's a lack of will to reorganize how we work. The review makes clear that climate change is not a future threat—it's reshaping health systems right now. The question is whether institutions can move fast enough to adapt.
Citas Notables
Climate-related hazards threaten human, animal, and environmental health in interconnected ways and call for coordinated One Health responses.— The systematic review published in Climate
Addressing climate-related health threats requires a shift away from fragmented responses toward a holistic One Health approach.— The researchers
La Conversación del Hearth Otra perspectiva de la historia
Why does it matter that less than 1 percent of climate-health research uses a One Health framework? Isn't the research still being done?
The research is being done, but in silos. A malaria researcher studies how temperature affects mosquito breeding. A mental health researcher documents anxiety in flood-affected communities. A water engineer works on contamination. None of them are talking to each other. You miss the whole picture—how a flood doesn't just spread disease, it also traumatizes people and overwhelms hospitals at the same time.
So what would integrated research actually look like?
It would mean epidemiologists, ecologists, veterinarians, and mental health experts designing studies together from the start. Instead of asking "how does climate change affect malaria?" you'd ask "how do climate shifts in this region affect disease vectors, wildlife, water systems, and human communities all at once?" Then you'd design interventions that address all of those at once.
The review mentions vulnerable populations—women, children, Indigenous peoples. Why are they hit harder?
They're hit harder because they have less choice. A smallholder farmer can't just move if floods destroy crops and contaminate water. An older adult in a rural area can't access a hospital if the health system collapses. Indigenous communities often live in ecosystems that are changing fastest. And women often carry the burden of caring for sick family members while having less access to resources themselves.
What's the most concrete gap the research identifies?
Early-warning systems. We can predict where heatwaves will hit, where floods are coming, where disease outbreaks might emerge. But most health systems, especially in poorer countries, don't have the infrastructure to act on that information. You need trained workers, supplies, communication networks. That's not glamorous research, but it's what saves lives.
Is there any reason to think this will actually change?
The research is clear about what needs to happen. Whether institutions move fast enough—whether funding flows toward integrated approaches instead of fragmented ones, whether countries actually embed climate risk into health planning—that's a different question. The science is there. The will is what's uncertain.