As the world warms by more than 1.5 degrees Celsius, many parts of the world will experience more severe heat waves, a new study warns. A person cannot survive outdoors for more than a few hours. Catastrophic heat waves can result in mass deaths, especially when people are unaccustomed to high temperatures and buildings are ill-equipped for them.
“We’re talking about extreme heat waves that are significantly different from historical norms and cause significantly higher mortality rates.” – Carter Powis of the University of Oxford tells New Scientist magazine. “Especially in Europe and North America, there will be a huge increase in the incidence of such events as the world warms by 1.5 to 2 degrees Celsius.”
Normally, the human body cools down by producing sweat, which evaporates and dissipates heat. But when humidity is high, sweat evaporation slows down. Experiments show that the sum of heat and humidity, measured using the so-called wet-bulb temperature, is greater than 31.5°C when the human body performs normal, everyday activities outdoors. It can no longer cool itself.
Scientists have named this limit “Unaffected Thermal Stress”, because sweat cannot compensate for extreme conditions. Without cooling measures such as cold water, fans or air conditioning, death occurs within hours. This applies to everyone, including young, healthy people.
A recent study conducted by researchers from the University of Oxford and the Woodwell Climate Research Center in the US analyzed data from thousands of weather stations around the world. The researchers found that 4 percent of them have experienced at least one six-hour extreme heat stress event since 1970, and the frequency of such events has doubled by 2020.
However, such extreme conditions are found in places that have traditionally been considered the warmest – the Persian Gulf, the Middle East, the Red Sea coast and the northern Indian plains. Residents there are aware of the threat of extreme heat and have learned to offset its effects to some extent.
But the days of extreme heat only occurring in the tropics are becoming a thing of the past. The researchers’ analysis based on climate models shows that extreme heat stress is quickly spreading to other regions.
At 2°C above the pre-industrial average, on average a quarter of all the world’s meteorological stations will experience extreme heat stress at least once per decade. The climate crisis has already increased global temperatures by about 1.2 degrees Celsius.
“Even with a moderate increase in global average temperature, the range and frequency of irreversible temperature extremes will increase dramatically. This means In the future, a significant portion of the world’s population will be exposed to these irreversible environmental conditions.“- write the researchers. They warn that this is a real danger A catastrophic event can affect hundreds of millions of peoplebefore they are sufficiently adapted to the new conditions.
Scientists point out that the conditions prevailing there are particularly worrying East Coast and Midwestern parts of America and Central Europe. Areas that rarely offer intense heat today. In areas that already experience high temperatures, such as Arizona, Texas, and southern California, a 2 degree rise in temperature would result in periods of severe heat stress each year.
Global warming is already causing more intense and frequent heat waves, resulting in higher death tolls. It is estimated that there will be 62,000 heat-related deaths across Europe in the summer of 2022. However, most of them are over 65 and may already have health problems. Data for this year is not yet available, but this year’s summer was the hottest in recorded history in Europe.
The lack of mass deaths in places exposed to severe heat stress for long periods of time shows that Cooling agents are effective in preventing deaths. However, it is worrisome that in the past these conditions emerged quickly in places where people did not need cool buildings or air conditioning and were unprepared.
“Of all the effects of climate change What I personally worry about the most is the heat, these results made me even more concerned,” Powis says. “There are limits to what the human body can tolerate. If we cross this line, the situation will quickly turn bad. The death rate will increase dramatically. I fear that our bodies and our society are more susceptible to small changes than we think. Their impact on quality of life can be dramatic“.
The researchers stress that urgent measures are needed to adapt heatwave-prone areas to the impending threat. These include artificial cooling, building insulation, but also changes in social habits.
“I want to emphasize that the impact of heat on people’s health and well-being is preventable.” – Raquel Nunes of the University of Warwick in the UK tells the Guardian. “But as heat waves become more frequent, intense and long, urgent action is needed to prevent heat-related deaths.”
The World Health Organization estimates that between 2000 and 2016, the number of people exposed to extreme heat waves increased by 125 million worldwide. In Europe alone, between 1998 and 2017, more than 166,000 people died as a result. People. Only one heat wave that hit our continent in 2003 claimed 70 thousand lives. WHO warns that the effects of extreme heat are felt especially in cities. Heat waves can overload hospitals and emergency services, and disrupt water and electricity supplies.