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Chapter II Evidence for Global Climate Change

I. Frequent Occurrence of Heatwaves

In recent years, many regions worldwide have frequently experienced heatwave as-
saults. These extreme high-temperature events not only pose severe threats to human health
but also exert widespread impacts on socio-economic systems. The underlying mechanisms
of heatwaves are complex, involving interactions among multiple meteorological and climat-
ic factors.
Heatwaves are typically caused by abnormal atmospheric circulation patterns, particu-
larly when a high-pressure system persists over a region for an extended period. Such stable
high-pressure systems suppress cloud formation, allowing solar radiation to directly reach
the ground surface and rapidly elevate temperatures. Simultaneously, they prevent the influx
of cooler air masses, further exacerbating the high-temperature conditions. Additionally, the
urban heat island effect formed during urbanization contributes to the intensification and
prolongation of heatwaves. Buildings, roads, and other urban infrastructure absorb and store
thermal energy, releasing it during nighttime hours, resulting in significantly higher tempera-
tures in urban cores compared to surrounding rural areas.
The direct impacts of heatwaves on human health cannot be overlooked. In high-tem-
perature environments, the human body’s heat dissipation mechanisms become impaired,
easily triggering heatstroke, dehydration, and even fatal cardiovascular diseases. Vulnerable
groups such as the elderly, children, and people with chronic illnesses are particularly at
risk. During the 2003 European heatwave, over 70,000 deaths were estimated to be caused
by heat-related illnesses. Beyond direct health risks, heatwaves also intensify the burden on
public health systems and escalate demands for medical resources.
From a socioeconomic perspective, the economic losses caused by heat waves are
equally substantial. Agriculture stands as one of the most severely affected industries, as ex-
treme heat can lead to reduced crop yields or complete harvest failures, damaging farmers’
incomes. For example, India has experienced multiple heat waves in recent years that have
significantly disrupted the growth cycles of staple crops like wheat and rice. Additionally,
electricity demand surges during heat waves, straining energy supplies and potentially caus-
ing blackouts that impact industrial production and residential life. The tourism industry also
suffers, with reduced visitor numbers and declining hotel occupancy rates, subsequently af-
fecting revenues in related service sectors.
To mitigate the impacts of heatwaves, governments and various sectors of society are
implementing a series of measures. In urban planning, promoting green buildings and in-
creasing urban green spaces help alleviate the heat island effect. At the public policy level,
establishing early warning systems can promptly notify residents to take protective measures
and reduce health risks. Strengthening the emergency preparedness of healthcare systems
ensures effective responses to potential emergencies under extreme heat conditions. Interna-
tional cooperation is also crucial, as sharing data and technology to jointly research adapta-
tion strategies can reduce the negative impacts of heatwaves on a broader scale.

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