Climate change represents one of the most significant threats to global food security, with profound implications for food grain production across different regions. This comprehensive analysis examines the impact of changing climatic conditions on major food grains including wheat, rice, maize, and pulses across various geographical regions. The study synthesizes current research on temperature variations, precipitation changes, extreme weather events, and their effects on crop yields and production systems. Findings indicate that climate change impacts vary significantly by region, with some areas experiencing yield reductions of 10-25% while others may see marginal improvements. Developing countries and tropical regions face the greatest risks, with potential yield losses threatening food security for billions of people. The analysis reveals that adaptive strategies including climate-resilient varieties, modified cropping patterns, and improved water management are essential for maintaining food grain production under changing climatic conditions.