Lessons from Japan for tackling extreme heat in every day life

As extreme heat becomes the norm, preparing for rising temperatures has become a global imperative. Celeste Saulo, Secretary-General of the World Meteorological Organization (WMO), noted that the past decade has seen record-breaking heat year after year. The WMO has recently warned that there is an 80% chance that the world’s annual average temperature in 2024 will be surpassed by 2029.

Unprecedented heat poses serious health risks across the globe. Over 20,000 heat-related deaths were reported in Western Europe in 2024, with children and older adults particularly vulnerable to extreme temperatures.

Japan also experienced an extraordinarily hot summer in 2024, with more than 10 cities recording over 50 "extremely hot" days, defined as temperatures exceeding 35°C. Between June and September, heat-related fatalities reached a record high of 2,033.

According to the Tokyo Fire Department, over half of those transported for heatstroke in Tokyo were aged 65 and older. Among them, individuals in their eighties comprised the largest group at 1,886 cases, followed by those in their seventies at 1,530 cases.

Data from Japan’s Fire and Disaster Management Agency for June to September 2024 reveals that the most common location for heatstroke incidents was private residences (38%), followed by roads (19%), public outdoor spaces (13%) and workplaces, such as construction sites and factories (10.1%).

To address occupational heat risk, Japan recently strengthened its regulations. A revision to the Ordinance of Industrial Safety and Health came into effect on 1 June 2025. This requires employers to implement preventive measures against heatstroke. This regulatory shift aims to further enhance workplace safety as extreme heat events become more frequent.

As the number of older adults living alone continues to rise, so does the risk of heatstroke at home. According to Japan's Ministry of the Environment, nearly 90% of those who died from heatstroke at home were not using air conditioning. Promoting the appropriate and accessible use of cooling systems in households is, therefore, an urgent priority.

In the past, the Japanese government has called for energy conservation during the summer months, when electricity demand surges. For 2025, Japan’s Minister of the Economy, Trade and Industry announced that the Ministry would not make such a request during the summer months, citing sufficient electricity supply capacity. The reserve margin is expected to exceed 7%, well above the 3% threshold considered necessary for a stable electricity supply. However, the Minister cautioned that extreme weather events and potential power plant failures still pose risks, underscoring the importance of continued monitoring.

To help households preparedness, a number of municipalities, including Tokyo, Osaka, Fukuoka, Yokohama and Nagoya, have introduced subsidies for the purchase of energy-efficient air conditioners, supporting upgrades and new installations.

In May, the Tokyo Metropolitan Government proposed a JPY 36.8 billion ($255 million) supplementary budget proposal to waive the basic water service fee for all households during the four-month summer period. By alleviating financial pressure amid rising living costs, Tokyo aims to encourage air conditioner use and lower the risk of heat-related illnesses.

And, further community-based actions are in place at local level. Tokyo’s Shinagawa Ward has launched a programme to visit the homes of residents aged 75 and older twice between late July and early September. During these visits, staff will distribute free sports drinks and check on residents’ well-being. The initiative aims to prevent heatstroke and strengthen local support networks for vulnerable populations.

While air conditioners remain an essential tool for preventing heatstroke, indoor temperature and humidity levels can vary from room to room, limiting consistent protection. As a result, interest is growing in smart technologies that support real-time monitoring and better heat risk management at home.

Misawa Homes, for example, offers LinkGates, an IoT service that allows users to check room temperatures and control air conditioners remotely using a smartphone. The system includes a heatstroke alert function that notifies users when indoor temperatures exceed a critical threshold, enabling them to manage heat risks in individual rooms.

Smart home device provider, SwitchBot, promotes a solution combining its Hub 2, which monitors temperature and humidity, with its 3MP monitoring camera. This setup allows families to observe the real-time condition of children or older adults in other rooms and detect early signs of heat-related symptoms.

Wearable technology is also emerging as an effective tool for heat protection. The Canaria Heatstroke Prevention Watch is a wrist-worn device that detects increases in core body temperature, which is an early indicator of heat stress. The device alerts users with sound and vibration when risk levels rise. The Tokyo Metropolitan Government is distributing these devices to homebound older adults, teachers and students at public schools and essential outdoor workers as part of a broader public health strategy.

Recent heatwaves have claimed significant loss of life and caused widespread health impacts around the world. The World Economic Forum’s white paper, Insuring Against Extreme Heat: Navigating Risks in a Warming World, highlights that the deaths caused by extreme heat now outnumber those caused by floods, hurricanes, earthquakes and wildfires combined.

Addressing the threat of extreme heat requires long-term, sustained climate action. Equally critical are immediate measures that protect the most vulnerable from heat-related illness. Enhancing preparedness in everyday settings – at home and in the workplace – saves lives and builds societal resilience to the intensifying heatwaves anticipated in the years ahead.