The study shows that climate conditions also shape how resistance evolves in the environment. Higher temperatures can speed up bacterial growth and gene exchange. Extreme flooding can accelerate antimicrobial-resistance genes, or ARGs, spread in water systems | Photo Credit: lamyai

Climate change is linked to a 10 per cent global increase in antibiotic-resistance genes in Salmonella, according to new research that suggests warming temperatures and shifting rainfall patterns could accelerate the spread of hard-to-treat infections.

The study — conducted by researchers from multiple institutes including the Chinese Academy of Sciences and the University of Cambridge — analysed more than 4,80,000 Salmonella genomes collected from 139 countries between 1940 and 2023. Published this week in The Lancet Planetary Health, it found that temperature and precipitation levels are significantly associated with increases in antimicrobial-resistance genes, or ARGs, worldwide.

While salmonella is one of the leading causes of diarrheal disease in humans, responsible for tens of millions of infections each year, antimcrobial resistance is primarily driven by the overuse and misuse of antibiotics — causing resistant bacteria to survive and spread.

But the study shows that climate conditions also shape how resistance evolves and circulates in the environment. Higher temperatures can speed up bacterial growth and gene exchange. Extreme flooding can accelerate ARG spread in water systems, while drought can concentrate antibiotic residues and resistant bacteria in compromised water sources — all of which amplify AMR transmission.

Globally, the abundance of ARGs in Salmonella has increased by 38 per cent over the study period, with climate change accounting for 10 per cent of the rise. An overwhelming 82 per cent of countries showed rising ARG levels, with the strongest climate-linked surges observed in West Asia, North Africa, South Asia and Sub-Saharan Africa.

Looking ahead, the researchers project that ARG levels in Salmonella will continue to rise by 2100. However, if countries meet low-emission climate targets and strengthen responsible antibiotics use, the level of the ARGs could be 24 per cent lower than in the highest-emission scenario. 

“These findings highlight the importance of mitigating climate change as a strategic intervention to curb the spread of ARGs and ultimately to combat the global challenge of antibiotic resistance,” the authors wrote. Addressing climate change, alongside robust “antimicrobial stewardship” is “essential to safeguard public health and ensure the effectiveness of antimicrobial therapies in the future,” they wrote. 

More stories like this are available on bloomberg.com

©2026 Bloomberg L.P.

Published on May 27, 2026