Predicting the Weather

With an ironic twist worthy of an O. Henry story, climatologists are predicting possible relief from the drought in California. The catch? The thing that’s going to bring rain is likely the harbinger of a major cyclical change in the Pacific Ocean that could speed the rise of temperatures across the globe.

Scientists at NASA have described a patch of unusually warm water off the Pacific coast of the US. Formally known as the Pacific Decadal Oscillation (an informally as “the blob”), the phenomenon recurs every few decades. The warmer water off the coast will likely lead to El Niño weather patterns, which would mean more precipitation in southern California and across the southern US.

In the 1990s, NASA says, the western Pacific Ocean experienced a cool phase, which caused a slowing in the increase of average global temperatures. Now that the ocean is in a warm phase, global temperatures are likely to increase more rapidly. On a local scale, the warmer waters are damaging marine habitats, killing sea birds, and resulting in a disruption of the marine food chain.

There is some disagreement, though, about how significant this latest warming period is and how long it will last. Ocean temperatures off the coast began rising in 2013. “Maybe it will go away quickly and we won’t talk about it anymore,” says a professor of atmospheric sciences at the University of Washington, “but if it persists for a third year, then we’ll know something really unusual is going on.”

This article has more detail on the phenomenon and its implications.