Increased Climate Warming Fueling an Upsurge in Atmospheric Water Vapor Streams

The West Coast of the United States is bracing itself for a potentially dramatic future, as scientists predict that by 2100, atmospheric rivers could cause such severe flooding that ocean levels could temporarily rise up to three times higher. This ominous forecast comes in the wake of the historic rainfall experienced by California in January 2023, which was also the result of an atmospheric river.

Atmospheric rivers are narrow bands of water vapor that form in the mid to high latitudes. They primarily transport water from tropical oceans toward the poles, causing heavy precipitation during landfall. These rivers can span several miles and carry immense amounts of water, up to 27 times the flow of the Mississippi River.

The January 2023 event in California resulted in over 20 deaths, widespread flooding, power outages, and landslides, causing billions of dollars in damages. The Pineapple Express, an example of an atmospheric river, carries tropical moisture from Hawaii to the U.S West Coast.

Atmospheric rivers have both positive and negative effects. They contribute to 50 percent of California's annual precipitation, but they also cause flooding, landslides, and ice shelf melting. Climate change has amplified the intensity and frequency of atmospheric rivers, with current atmospheric rivers carrying 5-15 percent more precipitation than before.

Regions up and down the West Coast, particularly California and the Pacific Northwest, will be at the forefront of the impacts of atmospheric rivers. Reducing greenhouse gas emissions is essential to mitigate the frequency of atmospheric rivers, and advocating for investments in flood infrastructure, water management systems, and forecasting technologies can improve resilience to disasters.

EarthTalk®, a nonprofit organisation that produces articles about environmental issues, provides more information about atmospheric rivers and other related topics. Roddy Scheer and Doug Moss are the producers of EarthTalk®. If you have questions for EarthTalk®, you can send them to [email protected]. Donations can be made to EarthTalk® via their website. For more information about EarthTalk®, visit their website.