“Greening should make sense”: why cities are overheating and how to deal with it

Due to the peculiarities of the urban environment, the temperature in cities is higher than in the surrounding countryside – road surfaces and dark building surfaces accumulate heat, dense buildings slow down winds, impair air circulation, and lack of vegetation leads to insufficient evaporation. moisture. Automobiles, industrial plants, and other sources of extreme heat contribute to the rise in temperature. Areas that get hotter than their surroundings are called heat islands.

Such heating (and in some large cities the temperature is 10-15 ° C higher than in nearby areas) can be harmful to health, especially on already hot days – the heat often leads to excessive death of the population, which leads to a high load. cardiovascular system and other organs. In cities, heat islands, landscaping and the formation of reservoirs – the creation of “green” and “blue” areas are fought.

However, according to Chinese scientists from the City University of Hong Kong, Xian Jiaotong-Liverpool University and other research centers, such measures are practically useless.

The scientists analyzed meteorological data and data on daily mortality in Hong Kong for the years 2008-2017. As it turned out, with a temperature increase of 1 ° C above 29.61 ° C, the mortality rate increased by 5.7% in areas with low landscape level, by 5.4% in areas with average landscape level, and by high – by 4.6%. landscaping level. For areas near water bodies, mortality rates were 7.5% for areas with little water and 3.5% for areas with lots of water.

“No significant effect of the green and blue zones on the risk of heat-related death was observed in Hong Kong.

“These results question the existing evidence for the important protective role of green and blue areas in reducing the risks of death associated with rising temperatures.”

The results of the study were published in the journal Science of The Total Environment.

However, Boris Revich, head of the laboratory for estimating the quality of the environment and public health at the Institute of Economic Forecasting of the Russian Academy of Sciences, says the results obtained in Hong Kong should not be extended to other regions. Apparently, the point is not in the inefficiency of the approach, but in the peculiarities of the location of the territory itself.

“I was in Hong Kong, this is a totally unique city close to the sea and mountains. It is not an amphitheater like Yalta or Athens, but located close to it. “Therefore, there are such complex circulation processes within the city that I don’t think neither the green spaces nor the water systems help cooling,” he said.

At the same time, in regions with conditions similar to those in Russia, landscaping and the creation of reservoirs bring positive results, Revici said.

“A positive example is Nur-Sultan, the capital of Kazakhstan, where a forest ring has been built around the city. “This has helped reduce extreme anthropogenic warming,” he says.

In Moscow, the city center and its northern part heat up the most, thermal radiation is less in the southwest, and it is maximally reduced near parks and reserves (Losiny Ostrov, Izmailovsky Park).

Revich notes that the establishment of infrastructure in city parks in Moscow and other cities is also a positive initiative. In the park areas, the temperature is lower and there is always the possibility to hide in the shade, and the possibility to spend their free time in various ways encourages residents to spend more time in such green areas.

Revici emphasizes that “Green must be meaningful”. – I want to give an example of how not to do it – this is Leningradsky Prospekt. Starting from Belorussky Station Square to the Third Transport Ring, where it is clear that the creators of this green boulevard did not even think of some kind of protective function, they planted trees just to get a beautiful picture.

There is no solid green veil. If it were at the edge of the sidewalk, the situation would have improved dramatically – the plantings would have kept the polluted and hot air masses away from the large numbers of cars.

If it is not possible to stay near parks and reservoirs in hot weather, you will have to escape on your own.

“Recent reports during the 2022 heat wave in the second half of July in Western Europe – France, Spain, Portugal, the United Kingdom – show that the death rate is increasing in this case. It is an obvious fact that hot weather increases mortality. The same thing happened to us in 2010 – the number of deaths from the heat due to this drought was very high, – the head of the Meteo prognostic center, meteorologist, climatologist Alexander Shuvalov told socialbites.ca. –

Individual means of saving heat are extremely important – air conditioning, plenty of water. This does not provide complete protection against the combined cumulative effects of day and night heat, but reduces the damage.

Calculations of Russian scientists to approveHe said that the reduction of green areas and the increase of residential areas will lead to an increase in temperature in Moscow by 2050, which is 2 degrees above the average today, significantly increasing the probability of this. extremely hot conditions dangerous to health and life against the background of general climate change.

Emphasizing that gardening attracts the attention of scientists not only in terms of climate regulation, but also as a means of protection against pollution, Revich emphasized that gas and dust-resistant tree species are grown for the landscaping of cities in the Donetsk coal basin.

Green spaces and reservoirs not only help regulate the climate in the city, but also have a beneficial effect on the psyche of the inhabitants.

For this reason, a study published in the journal by an international group of scientists Total Environmental ScienceIt showed that people living near forests and lakes during the COVID-19 pandemic were less likely to experience symptoms of anxiety and depression. At the same time, even the opportunity to look out the window only at the trees and the water had a positive effect.