This Working Group focuses on the planetary boundary of Novel Entities.
The group is currently working to expand the following initial statement, which summarises the boundary and its relationship with AMR, into a longer policy brief.
This Working Group is open to new members – please email CLIMAR.Network@exeter.ac.uk to join.
Novel entities are defined in the Planetary Boundaries model as “synthetic chemicals and substances (e.g., microplastics, endocrine disruptors […] anthropogenically mobilized radioactive materials)” [1]; i.e. substances that would not exist in Earth systems without human intervention. The model also considers novel entities to be those that arise due to “human modification of evolution, genetically modified organisms and other direct human interventions in evolutionary processes”. The impacts of these novel entities on Earth systems are understudied, including their interaction with the other planetary boundaries. The need to understand the type and quantity of novel entities the Earth system can safely tolerate is especially pertinent to AMR; where a lack of knowledge transgresses a key planetary health ethic the “right to know the risk” [2]. Antibiotics themselves can be novel entities, as too can their alternatives such as bacteriocins etc. Synthetic chemicals such as biocides and detergents [3], and heavy metals [4] can drive evolution and the emergence of resistance. The use of novel antimicrobials can have unintended consequences, such as the negative impact of early antibiotic exposure on various childhood conditions [5, 6] or the disposal of human waste containing antibiotic residues mixing with other pollutants in watercourses forcing the evolution of resistance [7]; the latter shows seasonal variations in the abundance and diversity of ARGs detected, which may be exacerbated by climate change. Environmental progenitor genes that can transfer to pathogens and evolve to form related groups of resistance gene variants with a clinical signature can also be considered novel biological entities [8]. These novel genes are prevalent in polluted environments, including in environmental bacterial strains, suggesting that bidirectional transmission and gene transfer events are common between human and environmental microbiomes [9]. Skewing microbiomes towards predominately resistant organisms reduces the safe operating space for AMU, necessitating increased use and development of further novel entities (antimicrobials). The use of novel entities is not always well regulated, compounding the challenge. The use and release of chemicals without adequate safety assessment (including the cocktail effects of chemical mixtures under different conditions), thus presents a key challenge to AMR and climate change, yet more than ~80% of chemicals registered in the EU are in use for ~10 years before undergoing safety assessment [10] and safety assessments that do occur rarely consider potential Earth system effects. We know that novel entities such as antimicrobials have accelerated AMR evolution. How climate change will affect AMU across all sectors requires further, systemwide study.