Based on the fact that the year 2023 was the warmest year on record in the history of the planet (NASA, 12/01/2024), therefore, in fiscal year 2021, total greenhouse gas emissions in Japan amounted to approximately 1.17 billion tons of CO2. This research performed a characterization of the variables CO2 emissions and vehicles in use, a normality test was applied to the data by Shapiro Wilk analysis, a Spearman correlation test resulted in a correlation of r=-0.5823; which means that there is an intermediate correlation between the two variables. Since the value of r is negative, it indicates an inverse relationship between the variables, growth in one variable is associated with a decrease in the other variable. A future projection was made using the least squares model, year by year, from 2024 to 2030, resulting in CO2 emissions of 1123 Mt in 2024 and a decrease in emissions of 1066 Mt by 2030, which continues to jeopardize the global environmental goals of maintaining the global temperature of the planet at less than 1.5 degreesC.