Resilient cities - Hong Kong report: extreme heat


Effects of extreme heat

The rise in temperature does not simply mean a reduction in winter clothing or an increase in demand for air-conditioning units/fans, but also brings about serious health risks and economic repercussions.

The likelihood of these heat-related conditions is increased in Hong Kong where the air temperature and humidity levels are particularly high. Both high temperature and humidity can affect the rate of sweat evaporation and hinder the human body’s ability to cool down. Additionally, climate change increases the rate of transmission and geographical range of various infectious diseases. For example, incidences of dengue fever have risen in Hong Kong as well as some other Asian countries. Dengue fever is an acute mosquito-borne infection caused by the dengue viruses, which leads to symptoms including high fever and severe headache. In serious cases, it may cause circulatory failure, shock and even death. 24 According to experts, dengue fever is becoming more prevalent as a result of climate change because the rise in temperature reduces the time required for mosquitoes to mature, increases their biting activity, shortens their dormancy period and shortens the rate at which the dengue virus matures within them. 25


Heat stress is a condition which occurs when heat causes pressure/discomfort to the human body and is influenced by air temperature,relativehumidity,windspeed as well as solar radiation. 22 The human body generates heat energy and a healthy temperature is maintained through the process of sweating and evaporation. An extreme heat environment is linked to serious health issues such as heat cramps, dizziness, nausea, fainting, as well as deaths from heat exhaustion, stroke, and cardiovascular disease. To highlight the seriousness of extreme heat, research jointly conducted by researchers from the Hong Kong Polytechnic University and the Chinese University of Hong Kong found that in a full week with at least five hot days and nights, there was a 15.6% increase in deaths. 23

22 23 bigger-killers-daytime 24 25

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