Threat 1: Health
Climate change, coupled with the heat island effect, poses a direct threat to human health.
Physicians note that when the human body is placed in a hot environment or under strong solar radiation, heat-related illness results from confusion of the central nervous system and disruption of the body's temperature regulation mechanism. Because Taiwan's summers are often accompanied by high temperatures and humidity, heat dissipation from the body becomes more difficult, and there is a relatively increased risk of illness.
Common heat-related health issues include heat exhaustion and heatstroke. The former refers to a situation when the body is placed in a hot and humid environment, causing excessive perspiration and loss of electrolytes. Symptoms of slight shock may appear, including dizziness, headaches, general weakness, nausea, and sometimes muscle spasms, mainly the result of body salt distribution disorders. Patients' body temperatures usually remain lower than 39oC, and as long as treatment is appropriate (providing additional water and salt, and reducing ambient temperature), the patient will gradually recover.
Heat stroke, which may follow heat exhaustion, is however much more serious. Under this condition, the body temperature may increase to more than 40.5oC. Because the body can no longer dissipate sufficient heat, the patient will have dry and red skin, and perspiration will almost cease. Other symptoms include a rapid pulse, convulsions and unconsciousness. Once the temperature reaches 42oC or above, fatal pulmonary edema, cardiopulmonary dysfunction or permanent brain damage are likely.
According to one study, the occurrence of heatstroke in the elderly is three times more likely than for ordinary adults. Typical contributing factors include poor physical adaptability, or a lack of air-conditioning. In 2003, when a heatwave swept across Europe, for example, the majority of the more than 30,000 deaths were among the elderly. Alcoholics and patients with cardiovascular disease or obesity are at particular risk.
Fig. 2: Days per year with maximum daytime temperatures over 37°C, various Taiwanese locations, 1961-2005 / The number of days with temperatures above 37oC have increased significantly only in Taipei City, from under five to over 12 per year. / source:C.-J. Shiu, S. C. Liu and J.-P. Chen, 2009: Diurnally asymmetric trends of temperature, humidity and precipitation in Taiwan, J. Climate, 22, doi:10.1175/2009JCLI2514.1, No. 21, 5635°V5649