Causes and Effects of the Recent Warming in the NE Pacific (Invited Presentation)

Strongly positive sea surface temperature (SST) anomalies have prevailed in the NE Pacific Ocean since late 2013.  The causes and effects of these anomalies, sometimes referred to as the “blob”, are summarized.  The waters of the region warmed relative to their seasonal norms due to the regional atmospheric circulation, which brought about unusual wind and surface air temperature patterns.  These patterns varied over the last three years, resulting in evolving distributions of SST anomalies.  These conditions have had marked impacts on the marine ecosystem, including massive mortality events for some seabird species, and a historically severe harmful algal bloom along much of the western coast of North America.  The recent warming represents a short-term climate event, rather than a new “normal”.  Nevertheless, it does provide some clues on how the North Pacific atmosphere-ocean system is liable to respond to global climate change.