Urban Heat Assessment, Heat Mitigation and Sustainability Promotion in Taiwan Compact Cities.

According to the worst-case scenario of global warming (SSP5-8.5), the temperature in Taiwan is expected to continue to rise in the future. The average annual temperature may rise to more than 1.8 ℃/ 3.4 ℃ by the middle /end of the 21^st century. And the number of days with high temperatures above 36 ℃ will increase 8.5 days/ 48.1 days by the middle /end of the 21^st century at various places in Taiwan. In short, people in Taiwan will have to deal with a really long and extremely hot summer for the future.

Though Taiwan will face more severe conditions in the future, there are no specific urban high temperature implementations and regulations comprehensively settled, and there is a lack of tools and mechanisms to effectively quantify or assess urban high temperature risks. Urban high temperature is not just a simple environmental phenomenon, but an important global issue involving environmental sustainability, human well-being, quality of life, and public health. For further identification of 1) the areas of higher urban heat risks, 2) the factors that affect the most, and 3) the assessment combining "built environment" and "social vulnerability" factors.

This study selected Taichung City as the demonstration target for urban heat risk assessment. By establishing quantitative and specific classification methods, it is possible to 1) comprehensively evaluate the performance of each district under high temperature, 2) identify the high urban heat risk characteristics of each district, which will help to take appropriate heat mitigation responses, and 3) through the classification, it is possible to identify areas with higher urban heat risks and areas with a trend of increasing risks in the future.