Photo/Illutration Bullet trains for the Hokuriku Shinkansen Line are swamped in Nagano in October 2019 after Typhoon No. 19 caused the Chikumagawa river to burst its banks. (Asahi Shimbun file photo)

Global warming added nearly 520 billion yen ($4.04 billion) to the economic damage wreaked by Typhoon No. 19 in eastern Japan in 2019, according to an international group of climate scientists.

The World Weather Attribution group said it is the first analysis of an impact of climate change on economic losses from a natural disaster in Japan. Scientists both at home and abroad suspect global warming contributed to the typhoon’s extensive damage in wide areas, including Tokyo.

Typhoon No. 19 brought record-breaking rainfall to more than 100 observation points over the 24 hours from Oct. 12, 2019, causing many rivers to flood. The Chikumagawa river burst its banks, inundating trains for the Hokuriku Shinkansen Line in Nagano. The typhoon left at least 100 people dead or missing.

Munich Re, a German reinsurer that calculates damages from natural disasters across the globe, estimated insured losses from the typhoon at around $10 billion (1.29 trillion yen).

Previous studies by the Meteorological Research Institute of the Japan Meteorological Agency and others found that global warming was responsible for an 11-percent increase in precipitation recorded around the Kanto-Koshin region after Typhoon No. 19 hit the area.

But the impact of global warming on economic damages from the typhoon remained unknown.

The WWA compared rainfall around the Kanto region on Oct. 12, 2019, with that calculated under the scenario that there was no global warming.

The results showed torrential rains, like those brought by Typhoon No. 19, are 1.67 times more likely to fall in the current climate, where the increase in the global average temperature exceeds 1 degree from pre-industrial levels.

That means $4 billion, or 40 percent of insured economic losses from the typhoon, can be blamed on the effect of global warming, according to the WWA.

The group also released a preliminary report that pointed out the impact of global warming in last year’s devastating flooding in Germany and other parts of Europe and record-setting heat waves in North America.

In their analyses, the WWA and the Meteorological Research Institute used a methodology called “event attribution,” which enables researchers to calculate the impact of global warming on the damage inflicted by a natural disaster, thanks to developments in simulation technologies.

More event attribution studies are cited as scientific evidence in reports by the Intergovernmental Panel on Climate Change, according to the WWA.

The latest findings were published on May 18 in the journal Climatic Change: (https://doi.org/10.1007/s10584-022-03344-9).

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