Texas Heat Index Rising Faster Than Temperature, Study Finds
Texas Heat Index Rising Faster Than Temperature, Study Finds - Yale E360
Big Bend, Texas. Pixabay
A new study of summer weather in Texas finds the heat index — an indicator of how hot it feels outside — is rising much faster than the temperature.
The reason, scientists say, is that warming is leading to a rise in humidity. Historically in Texas, severe heat would be paired with lower humidity, making it possible to cool off by sweating. But now Texas is seeing high heat and humidity together. In hot, muggy weather, the air is so saturated with water that sweat sticks to the skin rather than evaporating. As a result, it feels warmer than a thermometer alone would suggest.
In 1979, physicist Robert Steadman developed the heat index to indicate how such weather actually feels. But Steadman did not calculate the index for high levels of heat and humidity that are routinely seen today.
In 2022, scientists at UC Berkeley recalculated the heat index to account for more extreme weather. And in 2023, Berkeley physicist David Romps applied the updated heat index to the summer heat in Texas.
He found that while Texas has warmed by around 3 degrees F (1.5 degrees C) since the preindustrial era, on some scorching summer days it felt up to 11 degrees F (6 degrees C) hotter. His study was published in Environmental Research Letters.
Romps wrote that, compared to the temperature, the heat index offers “a more accurate picture of the extent to which global warming has increased heat stress.”
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