Cities Closed in a Cage of Heat Waves--Shanghai, Hangzhou, Dubai, and Doha--Mid-21st Century

Cities Closed in a Cage of Heat Waves--Shanghai, Hangzhou, Dubai, and Doha--Mid-21st Century

China's North China Plain and East Coast are becoming one of the hottest and most humid regions in the world during the summer months. Due to future climate change, it is predicted that the number of days when wet-bulb temperatures approach the tolerance limit of the human body will increase. When the wet-bulb temperature exceeds 35°C, the body's thermoregulation by sweating will cease to function, and there is a risk of fatal heat stress in a matter of hours. The combination of high population density and the heat island effect in megacities such as Shanghai and Hangzhou further amplifies this danger. These cities are also economic hubs, where outdoor labor and transportation infrastructure operations are essential, so during a heat wave there will be a real threat of reduced labor productivity and strained medical facilities.

Meanwhile, in Dubai and Doha in the Middle East, air conditioning has already been installed in public spaces to ward off the extreme summer heat, with temperatures approaching 50 degrees Celsius. Pedestrian walkways and outdoor commercial facilities are cooled, and air-conditioned bus stops and sidewalks have been installed. In Qatar, it is even more extreme, with air conditioning throughout stadiums, markets, and major sidewalks, making outdoor events and sporting competitions possible. However, such outdoor cooling entails enormous electricity consumption and greenhouse gas emissions, and has the paradoxical challenge of exacerbating climate change in the long run. It also risks widening the gap between those who can benefit from cooling and those who cannot and becoming a source of social division.