Overview
- A multi‑institution study published in The Lancet Planetary Health in May 2026 found that climate change was associated with about a 10% global increase in Salmonella antibiotic‑resistance genes between 1940 and 2023 while overall abundance rose by 38%.
- The team analysed more than 480,000 Salmonella genomes from 139 countries covering 1940–2023 to compare trends in resistance genes with changes in temperature and precipitation.
- Researchers report that higher temperatures speed bacterial replication and gene exchange, extreme floods spread resistant genes through water systems, and drought can concentrate antibiotic residues and resistant bacteria in weakened water sources.
- Eighty‑two percent of countries showed rising resistance gene levels with the strongest climate‑linked increases measured in the Middle East, North Africa, South Asia and sub‑Saharan Africa.
- Models project continued growth in resistance genes to 2100 under high‑emission scenarios, but project about 24% lower levels under low emissions plus stronger antibiotic use policies; authors stress these projections are uncertain and that antibiotic misuse remains the main driver of resistance.