‘Humid heat is going to be a much bigger threat than dry heat’
Areas around the Indus River Valley, East China and sub-Saharan Africa are likely to bear the brunt of high-humidity heatwaves that could have an adverse impact on human health, warns a research study.
गाँव कनेक्शन 2 Nov 2023 1:53 PM GMT
Is excessive humidity something to be concerned about? Very much, so says an interdisciplinary joint research study conducted by Penn State College of Health and Human Development, Purdue University College of Sciences, and Purdue Institute for a Sustainable Future, in the United States of America.
Even a rise by 1.5 degree Celsius in global temperatures could have devastating consequences to human health across the planet.
According to the study, this is of particular concern for 2.2 billion people of the Indian subcontinent, especially in India and Pakistan near the Indus River valley, one billion people living in Eastern China, and 800 million people of sub-Saharan Africa.
These regions would primarily experience high-humidity heatwaves. Researchers said that because these are lower-to-middle income nations, many of the affected people may not have access to air conditioning or other effective ways to mitigate the negative health effects of the heat.
The researchers have conducted 462 separate experiments to document the combined levels of heat, humidity and physical exertion that humans can tolerate before their bodies can no longer maintain a stable core temperature.
“As people get warmer, they sweat, and more blood is pumped to their skin so that they can maintain their core temperatures by losing heat to the environment,” co-author of the study, W. Larry Kenney, professor of physiology and kinesiology, the Marie Underhill Noll Chair in Human Performance at Penn State, said.
“At certain levels of heat and humidity, these adjustments are no longer sufficient, and body core temperature begins to rise. This is not an immediate threat, but it does require some form of relief. If people do not find a way to cool down within hours, it can lead to heat exhaustion, heat stroke and strain on the cardiovascular system that can lead to heart attacks in vulnerable people,” he added.
In 2022, the collaborators of the study demonstrated that the limits of heat and humidity people can withstand are lower than were previously theorised.
Research and experiments have revealed that humid heat is going to be a much bigger threat than dry heat. And the study strongly recommends that governments and policymakers re-evaluate the effectiveness of heat-mitigation strategies to invest in programs that will address the greatest dangers people will face.
Staying safe in the heat
Preliminary studies of older populations, found that older adults experience heat stress and the associated health consequences at lower heat and humidity levels than young people.
Citing decades of research, the researchers said reducing the emission of greenhouse gases, especially the carbon dioxide emitted by burning fossil fuels, is a priority. If changes are not made, middle-income and low-income countries will suffer the most.
As one example, the researchers pointed to Al Hudaydah, Yemen, a port city of more than 700,000 people on the Red Sea. Results of the study indicated that if the planet warms by 4 degree C, this city can expect more than 300 days when temperatures exceed the limits of human tolerance every year, making it almost uninhabitable.
The countries that bear the brunt of the heat stress will be those that are not wealthy and have a growing population. This, despite the fact that these are the areas of the world that have far less greenhouse gas emissions than the wealthy nations.
This research was supported by grants from the National Institute on Aging, the National Aeronautics and Space Administration, and the National Science Foundation.