There is a silent killer that claims more lives than hurricanes or floods: heat. Without going any further, the heat wave that hit Europe in 2003 left more than 70,000 dead, almost 20,000 of them in France. Many elderly Parisians were cooked to death in their apartments.
Year after year, the heat claims lives . Since 1986, the first year the National Weather Service warned of data on heat-related deaths, the heat death toll has been on the rise.
As greenhouse gases accumulate in the atmosphere, the death toll is expected to increase. Temperatures will likely continue to break records as carbon dioxide, methane and other gases continue to warm the planet. Heat waves (unusually warm weather that lasts two or more days) will likely be longer, hotter, and more frequent in the future.
Beyond the deaths, scientists are beginning to document other losses: heat seems to rob us of sleep or intelligence. “Heat has the ability to affect everyone,” says Rupa Basu, an epidemiologist with the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment in Oakland. We are all vulnerable.
Many see heat more as a nuisance than a threat, but climate change, extreme heat, and human health are intertwined. In 20 years it could be a very serious problem.
The number of days each year above 35 ° Celsius is expected to increase and average summer temperatures will reach new heights if greenhouse gas emissions remain so high.
The human body cannot tolerate excessive heat. The biological and chemical processes that keep us alive are best performed at a core temperature of 36 ° to 37 ° C, with slight variation from individual to individual. The body always tries to get rid of excessive heat. Blood vessels in the skin dilate and the heart rate increases to drive blood flow to the skin, where the blood can release heat to cool itself. In the same way, we sweat to refresh the skin.
With repeated exposure to high temperatures, the body can become more efficient at eliminating excess heat. But there is a limit to how much the body can adjust, which depends on the underlying health of the person and the temperature and humidity of the environment. If the outside is warmer than the body, the blood on the surface of the skin will not release heat. If the humidity is high, sweating will not cool the skin.
Forced to regulate heat without interruption, the body wears out. Heat exhaustion causes weakness, dizziness, and nausea. The ability to regulate heat breaks down and the core body temperature reaches or exceeds 40 ° C. In this case, we can suffer a heat stroke that can cause seizures or put us into a coma.
More sensitive groups
No one is immune to heat, but it affects some groups more than others. The elderly, considered the most vulnerable, have fewer sweat glands and their bodies respond more slowly to rising temperatures. Children have not fully developed the ability to regulate their temperature and pregnant women also have it more complicated due to the demands of the fetus. People with chronic diseases such as diabetes, cardiovascular disease, and obesity can have trouble dissipating heat. And of course, people living in poverty often lack air conditioning and other resources to withstand the suffocating conditions.
Researchers are discovering more ways that heat can affect us.
In sleep: the onset and duration of sleep are sensitive to temperature. The body cools down as it prepares for sleep; This decrease in core temperature is a signal to bring rest.
According to a study by the US Centers for Disease Control and Prevention, the higher the nighttime temperatures, the heavier the sleep.
It will also affect our ability to think and calculate. According to a small study presented in Austin, Texas, at the annual meeting of the American Meteorological Society, researchers concluded that during a heat wave, students without air conditioning got 6% fewer correct answers on math problems and a 10% less on other tests, compared to air-conditioned students. Heat can even increase the risk of stillbirth.
It is therefore imperative that there is a global push to reduce greenhouse gas emissions .
