In Fukagawa City, Hokkaido, located 100 kilometers northeast of Sapporo, the start time for the annual Fukagawa Summer Festival has been changed from morning to evening this year. Despite being in Japan's northern region, the average high temperature in July last year reached 29.1 degrees Celsius, an increase of 4 degrees over the past decade. A local restaurant owner remarked, "It may be difficult to enjoy the festival under the blazing sun now."
Japan's summer heat has become comparable to that of Southeast Asian cities. An analysis by the Nihon Keizai Shimbun of data from the U.S. National Oceanic and Atmospheric Administration (NOAA) for 2020-2025 revealed that the high temperatures and humidity in Tokyo during July and August are nearing levels seen in Bangkok and Singapore. The newspaper reported on July 5 that both temperature and humidity have risen compared to the 2000s and 2010s, marking a clear trend of 'tropicalization.' Over the past century, Japan's average temperature has increased by 1.44 degrees Celsius. This change prompted the Japanese government to designate days with temperatures exceeding 40 degrees Celsius as 'extreme heat days,' as the previous threshold of 35 degrees was no longer sufficient to describe the rising temperatures.
This heat is also impacting working hours. According to an international study published in the British medical journal The Lancet, the reduction in working hours due to heat in Japan is estimated at 43 hours per worker in 2024, equivalent to more than five days based on an eight-hour workday. For all employed individuals, the total annual loss amounts to 2.89 billion hours, double the average of 1.43 billion hours in the 2010s. The potential income loss due to heat in Japan is estimated at $49.4 billion (approximately 8 trillion yen), exceeding the annual public works budget of about 6 trillion yen. Last year, the number of heatstroke cases in workplaces reached 1,803, marking the highest number for two consecutive years.
In response to the rising temperatures, companies have been using air conditioning and providing work uniforms with fans. However, the increasingly hot summers have made it clear that merely cooling down is no longer sufficient. Major construction firm Obayashi Corporation has shortened work hours at 60 sites nationwide to 7 a.m. to 1 p.m. during July and August. Although they considered halting construction altogether, they recognized that stopping work would disrupt the income of day laborers and the entire supply chain, making a change in work hours more practical, according to Nikkei.
Electrical contractor Toei Electric has implemented a four-day workweek for workers on utility poles, allowing them to take every Wednesday off during July and August. The reduced workdays will be compensated for when the heat subsides. General contractor Konoike has also decided to increase holidays at construction sites from July to September, with plans to make up for lost work on Saturdays starting in October.
Changes are also occurring outside construction sites. Japan Post, responsible for the national postal network, has decided to suspend outdoor deliveries and pickups in areas under special heatstroke warnings. They prioritize employee safety, stating that it is more important than having mail delayed by a day or two. Yakult, which employs 30,000 door-to-door salespeople nationwide, is considering early morning deliveries.
Rising Demand for Heat-Related Products
The heat is also fostering new markets. Household goods company Kao is repeatedly testing the performance of 'cooling towels' designed to cool the neck in a laboratory simulating summer sunlight. When a researcher pedaled an indoor bicycle while wearing a cooling towel, the thermography screen showed a rapid change from red to blue on the neck. In response to requests from construction companies stating that one hour of cooling is insufficient, the goal is to double the duration of cooling. Workwear company Workman has introduced summer work uniforms designed for temperatures up to 45 degrees Celsius. Research firm Global Information predicts that the global market for heat countermeasures will grow from approximately $2.8 billion in 2025 to $4 billion by 2030.
However, there is no way to prevent the heat itself. Takuya Shinohara, a senior researcher at the Nissay Foundation, emphasized the importance of shifting from 'cooling people' measures to reducing the time people are exposed to heat. He suggested adjusting work hours to early mornings or evenings and modifying labor hours throughout the seasons.
* This article has been translated by AI.
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