As temperatures rise and weather extremes intensify, new evidence reveals how climate stress and weak health systems are accelerating antibiotic-resistant infections across the Western Pacific, and why coordinated climate, AMR action is urgently needed.
Study: Climate change and antimicrobial resistance in the Western Pacific: a mixed-methods systematic analysis. Image credit: Fahroni/Shutterstock.com
A recent study published in The Lancet Regional Health, Western Pacific finds that changing climatic conditions and socioeconomic vulnerabilities jointly shape antimicrobial resistance (AMR) risks in the Western Pacific region, highlighting the urgent need for establishing integrated AMR, climate surveillance networks.
Climate change accelerates AMR through biology and infrastructure
Increasing environmental temperatures have been linked to accelerated bacterial growth, higher mutation rates, and enhanced horizontal gene transfer, thereby increasing the risk of AMR. Similarly, increased rainfall and extreme weather events have been found to increase the expression and spread of certain antibiotic resistance genes in the environment by damaging sanitation and wastewater infrastructure, particularly in settings with limited climate resilience.
Antimicrobial medications that are primarily used to treat infectious diseases face the major challenge of AMR, leading to increased disease burden, particularly in low- and middle-income countries. Recent estimates indicate that bacterial AMR was associated with 4.71 million deaths in 2021, which has been projected to reach more than 8 million deaths annually by 2050.
With the increasing severity of climate change and AMR worldwide, it has become essential to understand the interplay between these two significant public health threats, especially in regions with weak healthcare infrastructure and low economic development.
The Western Pacific Region, one of the six regions of the World Health Organization (WHO), faces unique challenges related to climate variability, high population density, and socioeconomic disparities, which demand targeted analysis. In this 2026 mixed-methods systematic analysis published in The Lancet Regional Health, Western Pacific, researchers aimed to provide comprehensive insights into the climate, AMR interplay in the Western Pacific Region, while accounting for differences in data availability across countries.
Higher temperatures linked to rising AMR-related deaths
The systematic analysis of 18 primary quantitative studies, including epidemiological, environmental, and laboratory-based studies, revealed that increasing environmental temperature is associated with intensified AMR risks in the Western Pacific Region through higher infection rates, increased antibiotic use, and indirect disruption of healthcare and sanitation systems, with chronic warming trends playing a more consistent role than isolated extreme events.
The quantitative analysis revealed that a 1 °C increase in the mean ambient temperature is associated with higher AMR-attributable mortality from carbapenem-resistant Acinetobacter baumannii and carbapenem-resistant Pseudomonas aeruginosa, with pathogen-specific differences in effect size, while associations were weaker or not statistically significant for some other resistant pathogens.
The analysis of environmental and mechanistic evidence revealed that increased temperature primarily contributes to AMR risk by significantly increasing the total abundance of antibiotic resistance genes, particularly multidrug-resistance and high-risk genes, as observed in soil, water, and other environmental reservoirs, although the strength of evidence varied across study designs and ecological settings.
Rainfall events also showed significant associations with the spread of antibiotic resistance genes, facilitating their transmission and proliferation from ambient air to soil. The increasing trend of global warming was also found to be associated with increased soil temperature and moisture, leading to altered microbial composition and increased abundance of antibiotic resistance genes.
The analysis of climatic and socioeconomic factors across Western Pacific countries revealed that increasing temperatures, rainfall, and fine particulate air pollution (PM2.5) are associated with higher mortality from antibiotic-resistant bacterial infections, as indicated by pathogen-specific regression models, although these associations varied across bacterial pathogens.
However, socioeconomic and health system indicators showed heterogeneous effects across pathogens. Better governance, as indicated by improvements in perceived levels of public-sector corruption, was significantly protective against AMR-attributable mortality, particularly for carbapenem-resistant Pseudomonas aeruginosa.
Climate resilience becomes central to AMR prevention
The study highlights the substantial influence of increasing ambient temperature and rainfall on AMR-attributable mortality in the Western Pacific Region. These climatic effects, however, are closely associated with complex socioeconomic conditions, including healthcare capacity, governance quality, and population density, which may either amplify or mitigate their influence.
AMR is a matter of global equity as its burdens disproportionately affect low- and middle-income countries. Mitigation efforts under climate stress, thus, require multi-sector governance.
Being a typical One Health problem, the governance of AMR requires a One Health approach, which is an integrated, collaborative, and multidisciplinary strategy that aims to sustainably balance and optimize the health of humans, animals, and ecosystems.
The WHO, together with other international organizations, has demanded a multi-sector One Health response to recognize the significant human, animal, and planetary health impacts of AMR and to emphasize the need for collaboration, communication, and coordination across relevant sectors.
As observed in the study, socioeconomic vulnerability and distinctive climate have made AMR management more challenging in the Western Pacific Region, where evidence remains unevenly distributed across countries, with a greater concentration of studies from larger economies. Countries with low socioeconomic status often face challenges in sufficiently investing in AMR and climate control strategies.
People living in these countries also experience challenges arising from quality healthcare unavailability or inaccessibility, poor infrastructure and resources, and lack of awareness. These challenges increase their reliance on over-the-counter antibiotics, which contributes to misuse and increased risk of AMR.
These health disparities highlight the urgent need to address the special challenges faced by low- and middle-income countries to reduce the global burden of AMR. Specific measures must also be taken to promote fair and coordinated development.
With approximately 5.2 million projected cumulative AMR-related deaths and around USD 150 billion in economic losses by 2030, the Western Pacific Region is under an alarmingly high threat. The framework proposed by this study may help control these threats through real-time monitoring of AMR spikes during climatic stress, multi-sector governance, implementation of climate-tolerant health systems with strict antimicrobial treatment policies, and regional collaborative efforts on fund sharing and data exchange.
Secondary-treated wastewater still transfers antibiotic resistance to fresh produce