There is increasing recognition of the hazards to human and planetary health posed by both climate change and antimicrobial resistance (AMR) globally. A recent report from the Intergovernmental Panel on Climate Change suggests that climate change may lead to 250,000 excess annual deaths by 2050 due to heat, undernutrition, malaria, and diarrhoeal disease, and the Institute for Health Metrics and Evaluation estimates that 4.95 million infectious disease deaths were associated with AMR in 2019. However, relatively little research has been conducted to characterise the interplay between these two phenomena. In a recent scoping review published in The Lancet Planetary Health, authors assess the strength of published evidence of shared drivers of climate change and AMR, highlight outstanding research gaps, and make the case for integrated and interdisciplinary approaches to addressing these gaps.

Key findings included some published evidence of so-called “harmful synergies” or ways in which the worsening issues of climate change and AMR can have mutually reinforcing effects. Examples included studies of how rising temperatures, increased humidity, and extreme weather events can contribute to the growth and spread of commonly drug-resistant bacteria like Escherichia coli and Staphylococcus aureus. Examples of climate change potentially driving AMR were also cited, including extreme weather events (e.g. floods and hurricanes) that disrupt sanitation infrastructure, leading to outbreaks of waterborne diseases like cholera and typhoid. These drive greater antimicrobial use (AMU), accelerating resistance. In addition, climate-induced migration events may lead to crowding and disruption of health systems and sanitation, which further heightens the risk of infectious disease transmission, leading to additional opportunities for the emergence or acquisition of AMR as well as increased AMU. 

The authors also identified the potential for “positive synergies” in addressing these related threats. Climate mitigation strategies, such as biofuel production and wastewater management, can simultaneously lead to reduced greenhouse gas emissions and lower antibiotic contamination in the environment. However, several key knowledge and research gaps remain. Co-authors noted a lack of comprehensive studies focusing on fungi, helminths, protists, and viruses in the context of climate change, and highlighted the need for additional empirical research on how specific climate hazards influence AMR across different settings and sectors, including healthcare, agriculture, and natural ecosystems. Additional interdisciplinary research and coordinated policies are necessary to address this dual threat, and a One Health approach that integrates environmental, animal, and human health will be essential for controlling the intertwined crises of AMR and climate change. 

There is additional cause for optimism – funders like the Wellcome Trust, the Bill & Melinda Gates Foundation, and the Novo Nordisk Foundation have committed funding to incentivise innovative, cross-disciplinary approaches to jointly tackling the wicked problems of infectious diseases, AMR, and climate change, and new AMR research initiatives like the Climate AMR (CLIMAR) network have recently been established to take on these uniquely complex challenges. These are interrelated problems that we cannot afford to ignore, and that will require all our collective abilities and experiences to solve.