As Texas reels from record-breaking rainfall and flash floods that overwhelmed parts of Kerr and Bexar Counties this July, the warnings shared at last year’s Climate Adaptation Conference feel all too relevant. In his 2023 keynote, “Extreme Rainfall or None, Inland Flooding,” Dr. Stu Waterman of the Climate Adaptation Center outlined how a warmer world is primed for more destructive rain events.
“At the bottom of everything here is the fact that the world is warming,” Dr. Waterman explained. “Warmer air holds more water… and it can hang on to it before it dumps it.” According to Waterman, that’s not a theory—it’s physics. For every 1°C of warming, rainfall intensity increases by roughly 7%.
His talk drew particular attention to Hurricane Ian’s 2022 impact on Central Florida. “Twenty-two and a half inches in Orlando. It was 24 inches at Fort Myers,” he noted. In Orange County alone, the storm caused hundreds of millions in damages—most of it outside designated FEMA flood zones. “FEMA flood zones are based on the history of flooding,” Waterman said, “but the climate is moving out from underneath them.”
That message now echoes across flood-damaged neighborhoods in the Texas Hill Country. Putting aside any role climate played in this recent and sad event, the type of flooding—intense rainfall, overwhelmed infrastructure, and widespread damage outside known flood zones—mirrors many of Waterman’s concerns.
“We move the average a little bit and we’ve introduced these extreme events that we’ve never seen before,” he warned. And as extremes become more common, recurrence intervals are shrinking. “The 1-in-50-year flood… it’ll be more like a 27-year event by the time we get to one and a half degrees [Celsius],” he said.
Waterman closed his talk with a forward-looking appeal: “We’ve got to find a way of migrating our planning into a future which isn’t the same as the past.”
As rescue and recovery efforts continue in Texas, the need to adapt flood planning to a warming, water-heavier world feels less like a forecast—and more like a nowcast.