The article reviews the impacts of changes in climate variability and the frequency of extreme events on biological and food systems, with a focus on developing countries. It highlights that most climate change impact studies focus on mean climate changes, which may underestimate the full impacts on human and biological systems. The authors present new analysis linking increased climate variability to future food insecurity and discuss how people adapt to climate variability and extremes. Key knowledge and data gaps are identified, including the interaction of different climatic stresses on plant growth and the impacts on crops, livestock, and farming systems. The need for improved understanding of the full range of impacts and investment in climate and environmental monitoring is emphasized. The article concludes by discussing research gaps and the need for a reframe of research questions to provide actionable answers for decision-makers in the food system.The article reviews the impacts of changes in climate variability and the frequency of extreme events on biological and food systems, with a focus on developing countries. It highlights that most climate change impact studies focus on mean climate changes, which may underestimate the full impacts on human and biological systems. The authors present new analysis linking increased climate variability to future food insecurity and discuss how people adapt to climate variability and extremes. Key knowledge and data gaps are identified, including the interaction of different climatic stresses on plant growth and the impacts on crops, livestock, and farming systems. The need for improved understanding of the full range of impacts and investment in climate and environmental monitoring is emphasized. The article concludes by discussing research gaps and the need for a reframe of research questions to provide actionable answers for decision-makers in the food system.