Responses to Health-Related Risks Caused by Rising Heat in the GBA Area

Rising urban temperatures have become a pressing public health issue across the Guangdong-Hong Kong-Macao Greater Bay Area (GBA), a megacity cluster of over 86 million residents. On 10 August 2026, the Hong Kong Observatory posted 36.9 °C at its headquarters, the city's highest official reading in 142 years of record-keeping, while a weather station in Sheung Shui registered 39.8 °C (Agence France-Presse). Because urban density, industrial emissions, and an aging population converge in the GBA, understanding how rising heat affects the GBA is critical for its health policies.

The GBA is warming through two reinforcing mechanisms: global climate change and localized urban heat-island (UHI) intensification. Hong Kong's annual mean temperature has increased at 0.14 °C per decade since 1885, with an all-time high of 24.8 °C in 2024, which is 1.3 °C above the 1991–2020 normal (Hong Kong Observatory). Across the wider region, the area of severe heat islands in the GBA grew 7.13 times between 2000 and 2020, expanding fastest in Zhongshan, Foshan, and Guangzhou (Deng et al. 8–12). The health consequences are also striking, as modelling by the University of Hong Kong estimated 1,455 to 3,238 excess deaths attributable to heat exposure in Hong Kong between 2014 and 2023, with people aged over 85 more than twice as vulnerable as the general population (Liu et al. 2–4). In Shenzhen, ambulance dispatches climb sharply on days above the local 95th-percentile temperature of about 30.2 °C, with elevated risks for cardiovascular, respiratory and mental-health emergencies (Asia-Pacific Adaptation Platform).

Public health responses have advanced quickly but unevenly. The Hong Kong Observatory issues Very Hot Weather Warnings combined with a Hong Kong Heat Index that integrates temperature, humidity, wind, and solar radiation. The Labour Department also operates a three-tier “Heat Stress at Work Warning” (Labour Department). These systems provided guidance on which employers, schools, and welfare agencies provided cooling measures, providing timely assistance to the public. Yet critics argue the system is insufficiently protective. For example, the record 36.9 °C reading in August 2026 triggered only the lowest amber alert, and the red and black tiers which would suspend heavy outdoor work have never been activated (Tse). For mainland cities, The China Meteorological Administration launched China’s first national heat-health risk warning integrated with mortality forecasting in 2025 (Xinhua). These tools can provide earlier risk communications and guide resting and working pensions, while facing challenges such as lack of bindingness and inequitable access to air conditioning across regions.

Rising urban heat is a documented cause of premature mortality that already rivals diabetes in Hong Kong, amongst other health-related issues surging in the greater GBA. Coordinated, health-based warning systems and binding worker-protection rules, applied consistently across the Greater Bay Area, are essential to turn policies into lives saved.

By Timmy Zhang

Bibliography

Agence France-Presse. “Hong Kong Records Hottest Day Ever as Typhoon Dolphin Fuels Heatwave.” The Guardian, 10 Aug. 2026, www.theguardian.com/world/2026/aug/10/hong-kong-heat-record-hottest-day-ever-typhoon-dolphin.

Asia-Pacific Adaptation Platform. “Assessing Heat-Health Risks and Advancing Local Adaptation.” AP-PLAT, National Institute for Environmental Studies, 2026, ap-plat.nies.go.jp/adaptation-database/list/case-study/db1469.html.

Deng, Fan, et al. “Urban Heat Island Intensity Changes in Guangdong-Hong Kong-Macao Greater Bay Area of China Revealed by Downscaling MODIS LST with Deep Learning.” International Journal of Environmental Research and Public Health, vol. 19, no. 24, 2022, article 17001, doi.org/10.3390/ijerph192417001.

Hong Kong Observatory. “The Year’s Weather – 2024.” Government of the Hong Kong SAR, 2025, www.hko.gov.hk/en/wxinfo/pastwx/2024/ywx2024.htm.

Labour Department. “LD Further Enhances Heat Stress at Work Warning System.” Government of the Hong Kong SAR, 27 Aug. 2026, www.info.gov.hk/gia/general/202608/27/P2026082700386.htm.

Liu, Zhenyuan, et al. Modelling the Excess Mortality Associated with Heat Waves in Hong Kong: 2014–2023. School of Public Health, The University of Hong Kong, 2025, phf2025.sph.hku.hk/assets/files/2-LIUZhenyuanRoro2.pdf.

Tse, Hans. “HK Labour Dept. to Revamp Heat Warning System after Record-Breaking Temps.” Hong Kong Free Press, 11 Aug. 2026, hongkongfp.com/2026/08/11/baffling-work-heat-stress-warnings-to-be-revamped-after-record-temperatures-trigger-only-lowest-alerts/.

Xinhua. “China Issues First National Heat-Health Risk Warning.” China Daily, 3 July 2025, www.chinadaily.com.cn/a/202507/03/WS68662f9fa31000e9a5739f80.html