Weatherwatch: rainclouds are travelling farther in warmer world
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- Travis Aerenson and colleagues at the University of Wyoming modeled atmospheric moisture movements across the US over more than three decades, finding warmer air is shifting both how much rain falls and where
- In the southwestern and southern plains, atmospheric moisture now travels 30 to 50 miles (50 to 80km) farther than it did 35 years ago and stays aloft an extra two to four hours before falling as rain
- The researchers found more evaporation is now occurring from ocean surfaces and less from land surfaces, a shift that alters atmospheric moisture pathways
- Published in Geophysical Research Letters, the study warns that moisture traveling farther means water security for more countries and states will increasingly fall outside their borders, requiring greater cross-border collaboration
Why it matters: Rainfall that was once a local resource is being redistributed across wider geographies, meaning downstream states and nations will increasingly depend on moisture carried in from far beyond their jurisdictions — directly raising the stakes of interstate and international water-sharing agreements.
