Study on climate change impact
on human health
The 27 th AIM International Workshop
October 1, 2021 ＠ Online
Kazutaka Oka（NIES）
Collaboration with Phung Vera Ling Hui, Yasuaki Hijioka (NIES)
Yasushi Honda, Kim Satbyul Estella (University of Tsukuba/NIES)CLIMATE CHANGE ADAPTATION PLATFORM

Study team
◼ Background• Climate change is threatening to human health domestically and globally.
• NIES CCCA has been organizing and strengthening a study team to conduct
studies on human health impact by climate change since 2020.

◼ Core member• Kazuatka Oka (NIES)• Phung Vera Ling Hui (NIES)• Hijioka Yasuaki (NIES)• Yasushi Honda (University of Tsukuba/NIES)• Kim Satbyul Estella (University of Tsukuba/NIES)

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Research projects
1. NIES adaptation research program (2021-2025)① Study on combined impacts of climate change and air pollution on humanhealth and projection of their impacts in Asia (PJ1-2a/PJ2-2a)② Study of climate change impact on human health and its future projection inJapan (PJ1-3e/PJ2-3e)

2. Collaborative research with LCCAC (2020; 2021-2023)• Study on climate change impact on human health3. JST e-ASIA Joint Research Program (2021-2023)• Climate change and human Health in Asia: current impacts, future risks, andhealth benefits of mitigation policies

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1-① NIES adaptation research program◼ Temperature increases• In Japan, the temperature is increasing at the rate of 1.24 °C/100 years.
• In Tokyo, the temperature is increasing at the rate of 2.5 °C/100 years.

Source：right：気象庁「気候変動監視レポート2019」；left：気象庁「気候変化レポート 2018 －関東甲信・北陸・東海地方－」

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1-① NIES adaptation research program◼ Heatstroke patients• More than 40,000 people are transported by ambulance each year due toheatstroke.

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1-① NIES adaptation research program◼ Heatstroke patients• The elderly population (>64 years) accounts for 50% of the patients.
• Heatstroke is a very serious issue for Japan’s aging society.
elderly group

Source：総務省消防庁「2019 年(５月から９月)の熱中症による救急搬送状況」

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1-① NIES adaptation research program◼ Description• A “heatstroke alert” isissued when the Wet BulbGlobeTemperature(WBGT) is expected toreach 33 °C or higher on agiven or next day.

• Target region✓In 2020, only KantoKoshin was issued.
✓expandedtootherregions from 2021.

Source：気象庁「熱中症予防対策に資する効果的な情報発信に関する環境省と気象庁の共同検討会の開催」

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1-① NIES adaptation research program◼ Wet Bulb Globe Temperature (WBGT)• The WBGT is a type of apparent temperature used to estimate the effect oftemperature, humidity, wind speed (wind chill), and radiation on humans.
• The WBGT is used by industrial hygienists, athletes, sporting events and themilitary to determine appropriate exposure levels to high temperatures.

Tw: Natural wet-bulb temperature (combined with dry-bulb temperatureindicates humidity)
Tg: Globe thermometer temperature (measured with a globe thermometer,
also known as a black globe thermometer)
Td: Dry-bulb temperature (actual air temperature)

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1-① NIES adaptation research program◼ Why WBGT of 33°C ?
• The numbers of patients and deaths increased significantly when the WBGT
exceeded 33 °C in case of Tokyo → 33 °C is set as the reference value.

出典：気象庁「熱中症予防対策に資する効果的な情報発信に関する環境省と気象庁の共同検討会の開催」

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1-① NIES adaptation research program◼ Background• The incidence of heatstroke when the daily maximum WBGT at 33℃ vary byregion.
• Need to investigate the regional characteristics of heatstroke and to verify thevalidity of this criterion.

◼ Objective① The impact of WBGT of 33℃ on the numbers of patients will be different byregion.
→ Calculate the incidence of heatstroke by prefecturegiven the reference value (WBGT of 33 °C)⚫ Incidence② The WBGT threshold for increases in the numbersof patients may differ by region.
→ Calculate the daily maximum WBGT at whichheatstroke start to increase by prefecture↓Threshold⚫ Daily max WBGT

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1-① NIES adaptation research program◼ Analysis Flow
• The analysis flow is shown below.
➢ Method• Construction of relationship between number of patients and daily max WBGT byprefecture.（quasi-Poisson glm）

Climate data

Calculations

・ Daily max WBGT
Data integration
Heatstroke
patient data

Development ofprediction model① Calculate the incidence ofheatstroke at the WBGT of
33 degree Celsius② Calculate
thedailymaximum WBGT at whichheatstroke occurs (withthe HS method).

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1-② NIES adaptation research program① Association between PM10, smoke haze, and under-5 mortality
in Klang Valley, Malaysia ⇒ Poster (P-28) by Vera-san② Investigating the association between temperature and under-5

mortality in Malaysia: an epidemiological approach
Temperature?

Health effects

What is the health risk if the population is exposed to variation in temperature?

③ Identifying important environmental variables in the association

with under-5 mortality in Malaysia: a random forest approach
Environmental variables

Air pollutant
variables

Weathervariables

Importantenvironmental
variable

Health effects

Other climaticfactors
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Conclusion• NIES CCCA has been organizing and strengthening a study team to conduct
studies on human health impact by climate change since 2020.
• We have been conducting various studies targeting not only for Japan but also
Asia under several projects.
• We welcome collaborative research with researchers in the AIM group!

17Thank you for kind attention