The National Weather Service in Birmingham warns a heat wave could start this weekend with feels like temperatures climbing into the triple digits across Alabama.
Though the Gulf South is no stranger to heat and humidity in the summer months, new research suggests human-caused climate change has influenced the intensity and frequency of hot and muggy weather.
A study by the non-profit Climate Central shows the number of “dangerous humid heat days” has doubled over the past 50 years across the globe and has risen more dramatically in the southeastern U.S. Dangerous humid heat days are when the temperature and humidity are so high that sweat cannot evaporate off of skin to cool the body.
Alabama now has nearly 40 days with dangerous humid heat each year – three times the number compared to a world without rising temperatures from human-caused climate change.
“The more that we burn fossil fuels, the more heat-trapping gases that we release into the atmosphere,” said Kaitlyn Trudeau, a Climate Central scientist. “You can think of it as kind of like wrapping a blanket around the entire Earth.”
The reason this affects more than heat is because warmer air holds more moisture than dry air. So hotter temperatures can also mean higher humidity. And as dangerous humid heat days show, sweat is not effective when the air is too muggy.
“There is a limit to which the air can no longer absorb any more moisture,” Trudeau said. “When that happens, it basically means your body cannot shed that heat that it's desperately trying to get rid of. So it gets trapped inside your body, and that gets deadly real fast.”
The study also shows how more dangerous humid heat days can lead to more heat-related illnesses. People who work outside, don’t have access to air conditioning, or are unhoused are the most vulnerable to heat risk. According to the National Weather Service, extreme heat is the number one weather-related killer in the U.S.
