Climate-driven changes in temperature, precipitation, and extreme weather are reshaping the ecology of infectious diseases by altering habitats, host and vector biology, and human exposures. Evidence compiled by the Intergovernmental Panel on Climate Change and analyses by public health researchers indicate that these shifts will generally increase the range, seasonality, and unpredictability of many climate-sensitive infections, though impacts will vary by pathogen and place. Jonathan Patz at the University of Wisconsin-Madison and Kristie Ebi at the University of Washington have both documented how warming and changing rainfall patterns influence malaria, dengue, and other vector-borne illnesses, and the World Health Organization highlights the role of extreme events in driving waterborne outbreaks.
Environmental drivers
Warming temperatures and altered precipitation change where and when disease vectors such as mosquitoes and ticks can survive and reproduce. Vector-borne disease risk can expand poleward and upward in elevation as previously unsuitable habitats become hospitable. Changes in rainfall and standing water influence breeding sites for Aedes and Anopheles mosquitoes, affecting transmission of dengue, Zika, chikungunya, and malaria. Sea level rise and coastal flooding can alter mosquito communities and increase exposure to saltwater-adapted vectors in some regions. At the same time, extreme rainfall, floods, and droughts disrupt water and sanitation systems, elevating the risk of waterborne diseases such as cholera and leptospirosis by contaminating drinking water and concentrating pathogens.
Human and social consequences
The health outcomes of these ecological changes are mediated by human factors. Population growth, urbanization, land use change, and migration interact with climate pressures to increase exposure and vulnerability. Zoonotic spillover risk rises where habitat loss and wildlife trade bring people into closer contact with animal reservoirs, a pathway highlighted in work by infectious disease ecologists and public health experts. Health systems with limited surveillance, diagnostics, and surge capacity will face greater difficulty detecting and controlling shifting disease patterns, amplifying risks for marginalized communities. Indigenous peoples and low-income populations often live in environmentally sensitive territories and have fewer resources for adaptation, making consequences both health-related and culturally significant.
Climate-driven changes also reshape territorial and cross-border dynamics. As vectors and pathogens move into new regions, political boundaries become less relevant to transmission, complicating control efforts and requiring transnational surveillance and cooperation. Seasonal shifts in disease windows can disrupt livelihoods, particularly in agricultural communities, and increase economic strain on health services.
Adaptation and evidence-based response
Effective response requires stronger surveillance, climate-informed early warning systems, targeted vector control, investment in water and sanitation infrastructure, and equitable health system strengthening. Integrating climate science with epidemiology, as advocated by the World Health Organization and researchers such as Jonathan Patz at the University of Wisconsin-Madison and Kristie Ebi at the University of Washington, improves forecasting and prioritization of interventions. Addressing underlying social determinants, respecting Indigenous knowledge and territorial rights, and reducing greenhouse gas emissions remain essential to limit long-term increases in infectious disease burdens. Adaptation can reduce but not eliminate risks; proactive, evidence-based public health planning is therefore critical.