Precipitation increases by 20% due to global warming; analysis of 6 cases including Chiba heavy rains - Japan Meteorological Agency/Ministry of Education, Culture, Sports, Science and Technology

By the 24th, the Japan Meteorological Agency's Meteorological Research Institute and the Ministry of Education, Culture, Sports, Science and Technology announced the results of a computer-based analysis of the extent to which global warming had an impact on six cases of heavy rain that occurred between August and September, including the Chiba heavy rains. The amount of precipitation has increased by about 20% compared to what would have been had there been no global warming since 1850, indicating that the risk of disasters has increased.

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The six cases occurred in August due to heavy rains in Chiba, as well as heavy rains in Toyama and Ishikawa prefectures and Fukui prefecture due to a front. In September, there was heavy rain in the Tokai region due to a front, heavy rain in eastern and western Japan due to Typhoon No. 24 and a front, and heavy rain in the northern Izu Islands and southern Kanto region due to Typhoon No. 25. Special warnings at Alert Level 5 were announced for both areas, resulting in landslides, river flooding, flooding, and flooding.

Temperatures will rise by 1.3 to 1.6 degrees compared to what they would be without global warming. The amount of water vapor in the atmosphere increased by 9.5 to 11.4%, and the amount of precipitation increased by 15.7 to 22.9%. The reason that the rate of increase in precipitation is about twice the amount of water vapor is because not only does water vapor directly turn into rain, but also because rising air currents have the effect of strengthening the development of cumulonimbus clouds.

Fukui Prefecture had the largest increase in precipitation at 22.9%, followed by Chiba Heavy Rain and Typhoon No. 25 at 22.8%.