Levon Azizyan, director of "HayHydromet" SNOCwritingis:
"Nights are warming faster than days, increasing the risk to human health
Scientists of the international research group found that global warming increases heat stress faster than conventional temperature measurements show. Even more worrying is the fact that the hottest nights of the year heat up faster than the hottest days, depriving the human body of the opportunity to recover from the daytime heat. The results of the research were published in the scientific journal Nature Climate Change.
Scientists assessed changes in heat stress using the Universal Thermal Climate Index (UTCI), which takes into account not only air temperature, but also air humidity, wind speed and solar radiation. Because of this, UTCI reflects much more accurately the conditions to which the human body is actually exposed.
The study found that heat stress on the 10 hottest nights of each year increased by an average of 0.32 °C per decade, compared to 0.27 °C on the 10 hottest days. This means that nighttime heat builds up faster, increasing the risks of overheating, cardiovascular complications, and death, especially among the elderly and people with chronic illnesses.
The most significant changes were recorded in the subtropical zones. Today, southern North America, southern Europe, northern and southern Africa, and South America have up to 50 additional days of severe or extreme heat stress compared to the 1970s.
The authors of the study also calculated that the share of the Earth's population that is exposed to extreme heat stress at least one day during the year increased from 16% to 22%. This means that over the past decades, approximately one billion more people have been added to the risk group.
According to scientists, the problem has long gone beyond the scope of individual heat waves. Heat stress has become more frequent, longer and more intense on almost all continents. Therefore, they call for the active implementation of early warning systems, the development of heat protection programs, the creation of a cooler urban environment and the widespread use of heat stress indicators in climate risk assessment.
