On May 28, the World Meteorological Organization (WMO) and the Met Office, the United Kingdom's national weather service, released a report on global climate forecasts, projecting that global mean temperatures from 2026 to 2030 will range between 1.3°C and 1.9°C above pre-industrial levels. The report also states that there is at least an 86% chance that the warmest year on record will occur within the next five years. In addition, the report predicts that the decline in sea ice and the rise in sea surface temperatures associated with global warming will increase precipitation in high-latitude regions, while reducing precipitation in the Southern Hemisphere, and will also increase the likelihood of El Niño events in the equatorial Pacific.

In fact, Europe is already experiencing heatwaves that seem to anticipate the WMO’s forecast. The United Kingdom has recorded its highest-ever temperature for May; heatwave warnings have been issued in western France; and record-breaking heat continues in Spain and Italy. Meanwhile, Japan experienced its second-warmest spring on record. Some areas of Kyushu even recorded temperatures exceeding 35°C (classified as a heat day in Japan) in mid-May. What was once considered “abnormal” heat is rapidly becoming the global norm and comparisons with historical averages are increasingly losing their meaning.

On May 22, the University of Tsukuba and Hokkaido University jointly announced their findings indicating that atmospheric rivers over Japan—long, narrow bands of intense water vapor transport that move large amounts of moisture through the atmosphere— have intensified by 8.3% over the past 42 years as global warming has progressed. The research concluded that this system has contributed to the occurrence of extreme rainfall events, including the linear rainbands that have caused devastating floods in recent years. If so, one reason localized downpours often described as "unprecedented" occur frequently every year may be attributed to the increasing water vapor transport of these atmospheric rivers, while the goals of the Paris Agreement drift further out of reach.

Over the decade from 2014 to 2023, flood damage in Japan amounted to more than 7.5 trillion yen. According to the Ministry of Land, Infrastructure, Transport and Tourism, about 40 percent of flood-damage incidents were attributable to inland flooding caused by rainwater overwhelming sewer systems, and in urban areas, specifically, the share rises to roughly 70 percent. In response, the government has stepped up efforts to reduce urban flood risks, including projects to expand the drainage capacity of sewer networks. Yet progress remains incomplete: as of 2022, the national average completion rate for these measures stood at only 62 percent.

As I was writing these lines, a Level 4 alert (indicating a high risk of flooding) was issued for the Kanda River, a small urban river running near my office, as Typhoon No. 6 was approaching. The Japan Weather Association forecasts that the number of typhoons heading toward Japan in 2026 will be around or above the seasonal average. I earnestly hope we can get through this summer without suffering serious damage from typhoons and torrential rains.

Takashi Mizukoshi, the President
This Week’s Focus, May 31 - June 4, 2026