Climate change impacts
In recent years, due to climate change and the heat island effect, ambient temperatures are increasing, especially in urban areas, and many incidents of heat illness have been reported. In addition, annual average temperatures have been rising around the world, including Japan, year on year. In particular, since the 1990s, the number of extremely hot days during the summer, hospitalizations, and fatalities due to heat illness have been on the rise, creating a serious social issue.
Adaptation activity
Since 2006, the Ministry of the Environment has been providing information on heat illness prevention through the "Ministry of the Environment Heat Illness Prevention” website (Fig. 1). This provides information on predicted and actual values of the heat index (WBGT) at 840 locations nationwide (see Note).
- Predicted WBGT values are for every 3 hours on the day, the next day and the day after.
- Actual WGBT values are those currently recorded at different weather stations.
Other basic information about WBGT is also provided.
With the renewal of the website in 2021, information for "Heat Illness Alerts" can also be checked in map or table formats (Fig. 2). Alerts are issued for prefectural districts according to Japan Meteorological Agency forecasts of WBGT values of 33 or higher. Announcements include not only predicted WBGT values and expected maximum temperatures, but also specific advice on how to avoid heat illness.
In addition, the website provides various ways of accessing information. For businesses that have their own ways of sharing information such as websites and e-mail newsletters, a service that provides actual and predicted WBGT data in CSV format is available, and for the general public, a heat illness alert and WBGT e-mail service is being developed.
Also available on the website are weekly summaries of WBGT values and the number of hospitalizations for heat illness, information on heat countermeasures such as the "Revised Guidelines for Heat Mitigation in Towns (Ministry of the Environment, March 2008)" public information material such as the "Heat Illness Environmental Health Manual 2018", and initiatives by relevant government ministries and agencies on heat illness.
Outputs / Expected benefits
The site was accessed about 47 million times in 2020, indicating that many people are using the service. The site is expected to help prevent heat illness through the provision of information in various forms.
Note: Measured values at 11 locations and estimated values at 829 locations
