Antimicrobial resistance is often described as a crisis of antibiotic misuse. That description is accurate but increasingly incomplete.
A growing body of research suggests that the climate is also influencing how resistant bacteria develop, survive, and travel. Higher temperatures can encourage bacteria to grow and exchange genes, and floods and heavy rains can disperse resistant organisms across farms, sewage systems, rivers, food supplies, and communities.
This changes the way we need to think about antimicrobial resistance, or AMR, as it is commonly known. We can’t just look at prescriptions or hospitals or livestock production anymore in isolation. Climate conditions, animal health, environmental contamination, sanitation, and food safety are all part of the same system.
An editorial in the journal Animal Diseases on 29 June 2026 advocated an integrated One Health approach to climate change and AMR. One Health acknowledges that human health is inextricably linked to the health of animals and the environment they live in.
The argument is particularly relevant to Salmonella, a pathogen capable of circulating among livestock, food products, wastewater, natural waterways, retail environments, and people. Because it moves across so many boundaries, Salmonella can reveal how resistance emerging in one part of the system may spread into another.
A Global Study of Salmonella Resistance
The warning is supported by a large international analysis of 488,232 Salmonella genomes collected from 139 countries and regions between 1940 and 2023.
Researchers reported that the average global abundance of antimicrobial resistance genes in Salmonella increased by 38 percent during the period studied. Climate change was associated with a further 10 percent increase in the abundance of these genes. Increases linked to climate conditions were identified in 82 of the 100 countries included in that part of the analysis.
These findings do not suggest that climate change is the sole cause of antimicrobial resistance. Poor sanitation, weak infection controls, farming practices and limited health infrastructure are still major drivers, as is antibiotic use.
The research shows that climate change may add to those existing pressures.
Higher temperatures may impede bacterial reproduction and survival. Increased temperatures may also promote horizontal gene transfer, a process by which bacteria exchange genetic material, including genes for resistance to antimicrobial therapy.
Extreme rainfall introduces a different risk. Floodwater and runoff can move animal waste, untreated sewage, resistant bacteria, and resistance genes across geographical and institutional boundaries. A contamination problem that begins at a farm or wastewater facility may consequently reach rivers, crops, food-processing systems, or residential areas.
AMR Is Not Confined to Hospitals
The traditional response to antimicrobial resistance has focused heavily on responsible prescribing and reduced antibiotic use. Those measures remain essential. Antibiotics should not be used unnecessarily, and healthcare and veterinary systems need strong stewardship programs.
Yet stewardship alone cannot control resistance that is already moving through water, soil, animals, food chains, and climate-disrupted infrastructure.
This is why the One Health framework matters. It replaces fragmented programs with coordinated monitoring across public health, veterinary medicine, agriculture, environmental management, and food safety.
Climate information could help authorities anticipate increased risk for transmission of resistant infections. Veterinary agencies, for example, could combine temperature and rainfall forecasts with reports of animal disease. Public-health officials could connect genomic sequencing data with wastewater monitoring, livestock movements, flooding events, and records of antimicrobial use.
Food-safety agencies may also need stronger surveillance after heat waves, floods, and severe storms. Such events can disrupt refrigeration, sanitation, transportation, water treatment, and routine disease monitoring at the same time.
The central challenge is anticipation. Governments and health systems have generally responded to AMR after resistant infections have already appeared. Climate-informed surveillance could help predict where risks are increasing before outbreaks become difficult to contain.
Lower Emissions Could Support AMR Control
The research also provides a reason to view climate policy as part of public-health planning.
Future modeling indicated that a low-emissions pathway, combined with stronger antibiotic stewardship, could reduce Salmonella antimicrobial resistance genes by 24 percent compared with a high-emissions scenario.
That projection should be interpreted carefully. Models cannot predict every future outbreak or account perfectly for political, economic, and ecological changes. Still, the finding points to an important policy conclusion: climate mitigation and antimicrobial stewardship may reinforce each other.
Reducing emissions will not replace infection prevention, responsible prescribing, vaccination, sanitation, or veterinary oversight. It may, however, reduce some of the environmental conditions that allow resistance to expand and circulate.
Vulnerable Countries Face the Greatest Pressure
The risks are especially serious for low- and middle-income countries, where climate vulnerability may overlap with high infectious-disease burdens, limited laboratory capacity, inadequate wastewater treatment, and restricted access to effective medicines.
Many health systems still lack affordable genomic sequencing, trained personnel, and reliable mechanisms for sharing surveillance data. Without those resources, resistant pathogens can spread for long periods before they are identified.
International cooperation will therefore be critical. Wealthier countries and global health institutions should treat sequencing capacity, sanitation, veterinary surveillance, and data-sharing infrastructure as investments in collective security, not as isolated development projects.
Pathogens do not respect borders, and neither do resistance genes. A resistant strain emerging in an animal population can move through trade, travel, migration, food distribution, or environmental pathways.
A Wider Definition of Prevention
The connection between climate change and antimicrobial resistance does not reduce the importance of careful antibiotic use. It expands the definition of prevention.
Protecting antimicrobial medicines now requires more than changing behavior inside clinics and farms. It requires resilient wastewater systems, safer agricultural practices, reliable animal-disease monitoring, climate preparedness, genomic surveillance, and rapid communication among sectors that have historically operated separately.
AMR and climate change are often presented as two different global emergencies. The latest evidence suggests that they are increasingly interacting within the same biological and environmental networks.
Public policy must catch up with that reality. The effectiveness of antibiotics may depend not only on how medicines are prescribed today, but also on how societies manage heat, water, livestock, sanitation, and climate risk in the years ahead.
