A new study by scientists at the University of California, Santa Barbara (UCSB) has found that Earth’s “atmospheric rivers” narrow bands of moisture in the air are no longer traveling along their historical paths. The report, published in the journal Science Advances, shows these sky rivers are unexpectedly shifting toward both the North and South poles, causing major disruptions to local weather and water supplies.
An Unexpected Shift in Global Weather Patterns
Zhe Li, who recently completed his doctorate in atmospheric circulation at USCB, worked with advisor Qinghua Ding to track the movement of these atmospheric rivers over the past 40 years. Using data from satellites, weather balloons, and ground stations, their analysis revealed a notable shift of several degrees of latitude toward the poles.
“Atmospheric rivers are shifting poleward in both hemispheres,” Li said, “bringing heavy rain and storms to higher latitudes, which could reshape precipitation patterns globally.”
The findings were unexpected, as climate models had not predicted this specific shift in storm paths. The researchers’ evidence suggests that the primary driver of this change is natural variability in ocean conditions, particularly variations in sea surface temperatures in the tropical eastern Pacific, rather than solely human-caused climate warming. This contrasts with a widespread assumption among many of their colleagues.
Consequences for Communities and Infrastructure
The shift is already creating practical problems for communities worldwide. Places that have historically relied on atmospheric rivers for their annual water supply are now facing drought and water shortages. Conversely, higher-latitude areas are now experiencing intense, previously uncommon storms that their infrastructure and flood maps are not designed to handle.
This poleward migration is compounded by the fact that a warmer atmosphere holds more water vapor, making these storms more intense when they do occur. Furthermore, warmer storms tend to drop rain instead of snow, which reduces mountain snowpack a vital natural reservoir for spring and summer water supplies.
The study underscores that past weather patterns are no longer reliable for future planning. Communities will need to update flood zones, expand water conservation and storage capacity, and implement improved warning systems to adapt to the new reality of unpredictable storm patterns.