Figure 3: The projected change in the number of very hot days in summer in Japan during the period of 1900 to 2100 (The result in Scenario "A1B" was used for the data from 2001 onward). If the maximum temperature of at least one of grids (approx. 100km X 100km) covering the Japanese archipelago exceeded 30°C, it was counted as one day. Since urbanization is not considered and the data are based on the mean value in a wide area, the absolute value cannot be directly compared to the observed data. Only the relative change should be taken into account.