Climate change is increasing the frequency, intensity and duration of heat waves in all regions of the world. And this rise in extreme temperatures in recent decades, a product of human activity, has put millions of people at serious health risks. This was revealed by two new investigations published at dawn this Friday in the magazine The Lancet.
One of the studies, led by Katrin burkart, a professor at the Institute for Health Metrics and Evaluation of the University of Washington, in the United States, affirms that, in 2019 alone, more than 356,000 people died from some disease derived from strong heat waves. In addition, 1.3 million people died from cold-related causes.
Deaths related to low temperatures increased 31% compared to 1990, but those related to hot weather grew 74%, more than double in the same period of time. “It is expected that the number of people with health problems due to heat will continue to rise as temperatures rise around the world,” warns the researcher.
Burkart acknowledges that, although cold temperatures currently have a greater impact on people’s health in most regions, the projection analysis he conducted with his colleagues finds that, in the short term, the effects Harmful from extreme heat may outweigh those from cold.
“This is very concerning because the risk of exposure to high temperatures appears to have increased steadily over decades,” explains Burkart. According to the researcher, the regions of the planet that will suffer the most from these consequences are places where it is already very hot, especially South Asia, the Middle East and many countries in Africa.
For example, in Niger, 0.67 deaths per 100,000 inhabitants were attributable to cold (157) and 13.96 deaths per 100,000 to heat (3,250) in 2019. Something similar happened in the West Sub-Saharan Africa region: 0.61 deaths per 100,000 were from low temperatures (2,800), but 6.31 deaths per 100,000 (29,000) were related to heat.
The study, which links deaths related to extreme temperatures with 17 specific causes of diseases, especially cardiorespiratory and metabolic, used data from 64.9 million deaths in nine countries that cover 29% of the world’s population, have climates with 95% of the global temperature range and represent 79% of the sociodemographic conditions of the planet.
A second investigation, also published in The Lancet and in which the teachers participated Ollie Jay Y Kristie Ebi from the University of Sydney (Australia) confirms that in addition to the increase in deaths, extremes of heat are associated with a high number of hospital visits, mental health problems, difficult pregnancies and higher costs in medical care. “Exposure to high ambient temperatures unnecessarily causes suffering and death,” read the study’s conclusions.
This work states that adults over 65, people with cardiopulmonary disease, and very young children are the most vulnerable to the effects of extremely hot temperatures. According to the researchers, very hot days or heat waves that used to be experienced roughly every 20 years are now seen more frequently and could occur every year by the end of this century if emissions of greenhouse gases are not stopped. greenhouse effect.
The study links deaths related to extreme temperatures with 17 specific causes of diseases, especially cardiorespiratory and metabolic
The study explains that the human body responds to excess heat in two main ways: redistributing blood flow to the skin and secreting sweat. “The brain regulates these physiological heat loss responses that are necessary to limit rises in temperature,” the research reads. This process requires the heart to pump harder and faster. This increases the demand for oxygen. Therefore, people with cardiorespiratory problems are more vulnerable. “This response can lead to a mismatch due to a high cardiac oxygen demand and this mismatch can lead to cardiac ischemia, heart attack and ultimately cardiovascular collapse,” the study reveals.
Jay and Ebi agree with Burkart that people in tropical regions who will experience higher temperatures could more frequently exceed the physiological limits related to heat tolerance in the coming decades. In other words, many more people could die faster from heat waves if the necessary measures are not taken. “The effects that exposure to extreme heat can have on the body present a clear and growing global health problem,” say the researchers.
Professor Jay explains that, although it is inevitable that much of the planet’s population will be more exposed to extreme heat in the future than it is today, it is still possible to reduce the consequences of this phenomenon. These rising temperatures, combined with a rapidly aging population, will put more people at risk for weather-related health effects.
“Amid stark projections about the growing effects of climate change, urgent investment in research and measures to combat the risks of extreme heat is critical for society not only to survive, but to prosper in a world that in the future will be more warm, ”says Ollie Jay. And he adds: “Many heat-related deaths can be prevented by mitigating climate change and reducing exposure to extreme heat.”
Researchers acknowledge that there are many “sustainable and affordable” options for reducing the effects of heat exposure if the issue focuses on how to cool the body rather than how to cool the air. Some of the main recommendations are: use of electric and misting fans, use a water spray or sponge, put on wet clothes and soak your feet in cold water. Other simple measures, the researchers say, “consist of short breaks in physical activity, staying well hydrated, and modifying protective clothing or equipment to improve ventilation.”