A new study claims that 30 percent of the world’s population is currently exposed to damaging and potentially deadly heat for 20 days per year or more, and according to the researchers, climate change is spreading this extreme heat.

Furthermore, the researchers note that without major reductions in emissions of greenhouse gases like CO2, up to three in four people will face the threat of dying from heat by 2100. The findings were published Monday in the journal Nature Climate Change.

A new study claims that 30 percent of the world’s population is currently exposed to damaging and potentially deadly heat. Image credit: Frank Neulichedl / Flickr / Climatechangenews.com
A new study claims that 30 percent of the world’s population is currently exposed to damaging and potentially deadly heat. Image credit: Frank Neulichedl / Flickr / Climatechangenews.com

Heatwaves are killing people around the world and may kill millions of people by 2100

Researchers also added that even with reductions, one in two people by 2100 will likely face at least 20 days of extreme heat that can kill them.

“Lethal heatwaves are very common. I don’t know why we as a society are not more concerned about the dangers,” said Camilo Mora of the University of Hawaii in Manoa, the study’s lead author, according to National Geographic. “The 2003 European heatwave killed approximately 70,000 people- that’s more than 20 times the number of people who died in the September 11 attacks.”

Dangerous heatwaves are more common than people realize, killing people in over 60 different parts of the world every year. Some of the most dangerous heatwaves that have been reported include the 2010 Moscow heatwave that killed around 10,000 people and the 1995 Chicago event that killed 700 people of heat-related causes.

Heatwaves have also killed people more recently. For the past two weeks, dozens of people have died in India and Pakistan’s current heatwave, where temperatures have spiked to a record 128 degrees Fahrenheit (53.5 degrees Celsius). Actually, heat has already killed people in the United States this summer, as two people died in Arizona’s Maricopa County from heat-related causes, and the county’s health officials said they were investigating 12 other deaths that may have been caused by heat too.

Lethal heatwaves affect elderly people more

Mora and his team, made up by a group of international researchers and students, looked at more than 30,000 relevant publications to find data on 1,949 case studies of cities or regions in which human deaths were linked to high temperatures. Deadly heatwaves have occurred in New York, Washington, D.C., Chicago, Los Angeles, Toronto, London, Tokyo, Beijing, Sydney, and Sao Paulo.

People who face the greatest risk of dying during a heatwave are those living in wet tropics, where only slight increases in the average temperatures or humidity can result in deaths. However, according to Mora, heat can be deadly even at a moderate temperature of less than 86 degrees Fahrenheit (30 degrees Celsius) if it’s combined with extremely high humidity.

Image credit: Portalgreece.gr

Heat has killed more people in the U.S. than tornados or other extreme weather phenomena, according to Richard Keller, a University of Wisconsin-Madison professor of medical history. Keller, who wrote a book about the 2003 European heatwave, explained that extreme heat “sneaks up” on us because we expect it to be hot during the summer.

The human body’s internal temperature oscillates between 98.6 to 100.4 degrees Fahrenheit (37 to 38 degrees Celsius); and if it gets any warmer, it’s fever. If temperatures rise, the body reacts by sweating as it tries to cool down. If our internal temperature rises to 104 degrees Fahrenheit (40 degrees Celsius), all-important cellular machinery starts to break down in response. Anyone with a body temperature above 104 degrees is in extreme danger and would require immediate medical attention.

If the heat index, which is a metric that combines humidity and temperature, reaches 104 degrees Fahrenheit, the human body begins to heat up to the ambient temperature unless something is done to cool down the temperature.

Heat affects more the young and the elderly, as they lack resources and are more socially isolated, making them vulnerable to extreme heat. The vast majority of 15,000 heat-related deaths in France during the 2003 heatwave were aged 75 years or older, many of whom were living on their own, according to Keller.

“Increasing inequality leads to increased deaths from heat extremes,” said Keller, according to National Geographic.

‘We’re running out of good choices for the future’

Keller believes that heat didn’t use to be a problem in areas like India or Pakistan, but heat extremes are now more common and more intense with climate change.

Thousands of people have died in India from deadly heatwaves in the past years. Another study published in the journal Science Advances found that the number of heatwaves in India killing over 100 people increased 2.5 times between 1960 and 2009. The study’s co-author, Professor Steven Davis at the University of California, claims that the increase is also due to climate change.

However, India’s mean temperature has only risen 0.9 degrees Fahrenheit (0.5 degrees Celsius)in the last 50 years, which is a mild increase compared to other areas of the world. Surface temperature measurements have shown that the Earth has warmed around 1.8 degrees Fahrenheit (1 degree Celsius) since preindustrial times, but these additional degrees aren’t evenly distributed. For example, the Arctic is 4.5 degrees hotter normally, but in November 2016, temperatures were 36 degrees higher than usual over most of the Arctic Ocean.

“Our attitude towards the environment has been so reckless that we are running out of good choices for the future,” said Mora. “For heatwaves, our options are now between bad or terrible. Many people around the world are already paying the ultimate price of heatwaves.”

Source: National Geographic