Assessing impact of climate change on medicinal plants through yield decline, metabolite variability and range shifts

Abstract Climate change is one of the most grave environmental problems of the 21st century faced by organisms on Earth. It adversely impacts organisms including medicinal plants which contribute greatly to the healthcare system. It affects growth, chemistry and distribution of medicinal plants used as a source of medicine by people globally. An increase in the levels of greenhouse gases (GHG) due to anthropogenic activities has led to the warming of the Earth. This has caused a disturbance in the normal weather patterns thus causing fluctuations in a wide range of climate variables. In turn this threatens the survival of various medicinal plants which have been extensively discussed in this review. This comprehensive integrative review discusses how climate variability affects medicinal plants focusing on three key dimensions: growth and yield, secondary metabolites and geographical distribution. Relevant literature was retrieved from Scopus and Google Scholar through a structured search using Boolean logic and analysed to identify common patterns and knowledge gaps. Based on the findings, it was derived that plant phenology, productivity, metabolic pathways and natural habitats are impacted by climate. Besides accumulating existing evidence, the review presents an integrated framework which links plant growth, secondary metabolite variability and therapeutic potential to climatic changes, proposes a vulnerability-based classification of medicinal plants as per climate risk and identifies key research gaps which require further investigation. The review also discusses conservation strategies and emphasises adopting a multidisciplinary approach to ensure sustainability and therapeutic reliability of medicinal resources in a changing global climate.