In this study, it has been attempted to quantify model climate change effects of the coming decades on energy demand and carbon dioxide emissions of a dominant building brigade under hot and humid climates on the southern coast of Iran, based on three stations of Bushehr, Bandar Abbas and Chabahar. In this research, the Meteonorm and DesignBuilder software have been used for climate and thermal simulation of building. One of the results of this study is the increase in temperature and relative humidity for the coming decades for all three study stations. The findings of this study showed that the average annual temperature for the 2060s compared to the present decade, will increase by 2.82 °C for Bandar Abbas, by 2.79 °C for Bushehr and for Chabahar it will reach 2.14 °C. This increase in temperature has led to an increase in discomfort warmer days and a decrease in discomfort cold days. But given the climatic type of the area, a decrease in the heating energy demand for the coming decades will not have a significant effect on the pattern of energy consumption inside buildings. Because for two stations of Bandar Abbas and Chabahar, more than 95% of the energy demand for the 2060s is for cooling energy demand, which is about 80% of energy for Bushehr. In total, due to the increased demand for cooling energy in the coming decades, this will further increase carbon dioxide emissions, which is higher in Chabahar than in other study stations.