Increased heat stress for the population of urbanized areas against the background of global climate change

Abstract

The combination of high temperature and relative humidity of the atmospheric air creates heat stress, which has a serious impact on the environment, society and the health of the population in urban areas. Using the example of the city of Kyiv, the paper investigated long-term changes in heat stress depending on global climate changes. Averaged monthly long-term climate data of the urban environment were studied, starting from 1981, based on monitoring data using the Copernicus Climate Change Service toolkit and data from the Borys Sreznevsky Central Geophysical Observatory. Predictive dynamics of temperature by conventional and wet bulb was investigated using OriginPro8 software. Data on the dependence of the frequency and unevenness of precipitation during the last decades are presented. The dependences of the value of the heat index (NI) on the temperature and air humidity for different observation periods were obtained. Over the past decade, Kyiv has seen a significant increase in average heat stress and the frequency of days and events with extreme heat stress. According to the obtained forecast estimates, in 2050 the heat index should increase by almost 30%, and the risk to the health of the population in the surrounding area and for workers in the open air will be interpreted as "high" levels at a relative humidity of 80%; "moderate" at a relative humidity of 50% and "low" at a relative humidity of 20%. The forecast temperature dynamics according to the conventional and according to the wet thermometer in the month of July at the end of different years is: 2021–2030 – 24.136°С and 26.24°С; 2030–2050 – 26.371°С and 28.918°С, respectively, with other equal conditions of the urban environment. An additional possibility of influence on the thermal dome appears already at the design stage, thanks to the variability of the placement of the projected buildings on the general plan, and the formation of individual buildings, in the correct area ratio green plantings to stone surfaces of facades and paving. The research data will be useful for the possible reduction of the size of the thermal dome over the city during the planning and reconstruction of the housing stock and the development of climate neutrality measures for the cities of Ukraine.