CLIMATE CHANGE & DISASTERS Climate Change Helped Fuel Heavy Rains That Caused Hill Country Floods, Experts Say
Warming ocean temperatures and warmer air mean there’s more water vapor in the atmosphere to fuel extreme downpours like those that struck Texas during the July 4 weekend.
Heavy rains over the weekend that pushed the Guadalupe River in Texas’ Hill Country to its second-highest height on record had by Tuesday resulted in more than 100 reported deaths, including 27 children and counselors from Camp Mystic. But as search and rescue teams and volunteers sweep the banks of the river for missing people, the number of confirmed deaths is expected to grow.
Climate scientists said the torrential downpours on July 4 exemplify the devastating outcomes of weather intensified by a warming atmosphere. These disasters, they said, will become more frequent as people around the world continue to burn fossil fuels and heat the planet.
“This is not a one-off anymore,” said Claudia Benitez-Nelson, a climate scientist at the University of South Carolina. Extreme rainfall events are increasing across the U.S. as temperatures rise, she said.
Warmer temperatures allow for the atmosphere to hold more water vapor, producing heavier rainfalls, she and other climate scientists said. This coupled with old infrastructure and ineffective warning systems can be disastrous.
“It is an established fact that human-induced greenhouse gas emissions have led to an increased frequency and/or intensity of some weather and climate extremes since pre-industrial time, in particular for temperature extremes,” the United Nations’ Intergovernmental Panel on Climate Change reported in 2021. “At the global scale, the intensification of heavy precipitation will follow the rate of increase in the maximum amount of moisture that the atmosphere can hold as it warms about 7% per 1°C of global warming.”
The U.S. government’s fifth National Climate Assessment, released in November 2023, says that “the number of days with extreme precipitation will continue to increase as the climate warms” and that “these changes in precipitation patterns can lead to increased flood hazards, impacting infrastructure, ecosystems, and communities.”
Central Texas is infamous for its flash flooding and arid soil, hard-packed ground into which water does not easily infiltrate. So when rain hits the ground, it runs off the region’s hilly terrain and canyons and accumulates into creeks and rivers rapidly, overwhelming them, causing them to rise quickly.
The flash flooding wasn’t a result of a full-strength storm, Benitez-Nelson said, but a remnant of a tropical storm. “That, to me, is really sad and deeply alarming,” Benitez-Nelson said. “Climate change is turning ordinary weather into these disasters.”
