Global warming likely linked to heavy rain in Japan | NHK WORLD-JAPAN News - NHKニュース

Japan's Meteorological Research Institute says its analysis has shown it is highly likely that global warming increased the amount of precipitation in parts of the country by about 20 percent, bringing record heavy rainfall to some areas from August to September.

The institute used high-resolution weather models to simulate the amount of rainfall that would have occurred if there had been no rise in temperature due to global warming in six cases, and compared the simulations with actual precipitation data. The cases included the heavy rains in Chiba Prefecture and the Hokuriku region, as well as Typhoon Dujuan.

In the case of Typhoon Dujuan, which caused landslides and flooding triggered by the collapse of levees mainly in Chiba and Kanagawa prefectures, the analysis showed that the amount of rain was 22.8 percent higher than that of the simulation without global warming. The results also suggested that the impact of global warming expanded the areas hit by heavy rain.

The findings indicated global warming likely increased the amount of rain by 22.8 percent in Chiba Prefecture, 22.9 percent in Fukui Prefecture from August 29 to 30, and 15.7 percent in the Tokai region on September 8.

The institute says the rise in temperatures is believed to have led to an increase in the amount of vapor in the air and the development of more rain clouds.

Kawase Hiroaki, who conducted the analysis, said that if global warming advances in the future, the amount of rain could further increase. He also said it is necessary to understand that the rainfall caused by typhoons and fronts is different from what it used to be, and to make preparations.