Microbial Inoculants for Climate-Resilient Food Systems: Ecological Limits, Context Dependency, and Evidence Gaps

Climate change, soil degradation, and the disruption of global nutrient cycles are placing unprecedented pressure on agricultural systems and global food security. These challenges are increasingly recognized as central concerns for planetary health, as agriculture simultaneously depends upon and alters critical Earth system processes. Microbe-based agricultural inputs (including biofertilizers, biostimulants, and biocontrol agents) have been widely promoted as climate-smart solutions capable of enhancing productivity, resilience, and environmental sustainability. However, despite rapid scientific and commercial advances, their performance in the field remains highly variable and strongly context-dependent. This review critically examines the evidence base underpinning climate-smart microbial solutions, with a particular focus on their capacity to confer climate resilience across diverse crops, soils, and climatic conditions. We synthesize current knowledge on the functional roles of beneficial microorganisms, including extremophilic and stress-adapted taxa, while highlighting key biological, technological, ecological, and socio-economic constraints that limit predictability and scalability. Special attention is given to evidence gaps related to long-term field performance, ecosystem-level impacts, and the trade-offs associated with widespread microbial deployment. We further assess recent innovations such as synthetic microbial consortia, microbiome engineering, advanced formulations, and data-driven decision tools. Then we highlight how these new technologies may address context dependency but still need validation under real-world conditions. Finally, we discuss policy, regulatory, and capacity-building considerations required to responsibly integrate microbial solutions into climate-smart agriculture frameworks. Overall, this review argues that microbial inoculants should be viewed not as universal inputs but as context-specific tools whose successful deployment depends on robust evidence, ecological sensitivity, and system-level integration. Advancing microbial solutions for agriculture will therefore require aligning technological innovation with broader planetary health objectives, ensuring that efforts to enhance agricultural productivity also support long-term ecosystem stability and resilience.