This article provides a long run perspective of climate change impacts mainly due to CO2 emission and subsequent rise of temperature on food security in Bangladesh. The trends of changes in food demand and production was estimated considering five different climatic scenarios (A, B, C, D and E) based on Intergovernmental Panel on Climate Change (IPCC). These scenarios were accounted from the base year of 2008 to 2050, 2070 and 2100. Based on these scenarios the probable yield of winter rice variety BR3 was estimated for the year 2050, 2070 and 2100 using Decision Support System for Agrotechnology Transfer (DSSAT) model. The outcome of DSSAT model reveals that if the present trend of the population expansion and economic development continues, the future food security situation would be aggravated by the end of this century. Besides, the study suggests that the condition of future food security would be more vulnerable under the five climatic changes scenarios. It was estimated that the shortage of rice might be 58 million tons, 55 million tons and 48 million tons for scenarios C, D and E respectively which might lead to the expansion of food seeking (attributed to rice) community up to 45.90%, 43.85% and 38.25% by the year 2100. Furthermore, study suggests some policy recommendations to meet the challenges of future food security under climatic variability considering the gap between demand and supply.