Where Are Marine Heat Waves Located?

GRAINCOM 2023: Dr. Olivia Kellner – Climate/Arable Land next 2 decades & Scott Yuknis – Marine heat waves, the latest example of climate change. Geneva, Switzerland May 15-17.

Fig. 1: Global SSTA analysis and where marine heat waves and oceanic cool pools are located with their tendency annotated.

Discussion: Beginning with the 2013-14 Northeast Pacific marine heat wave (MHW) known at the time as the “warm blob” regional very warm (and cool) ocean surface zones have accelerated and are affecting our climate. The most recent analysis identifying where MHW’s are currently located indicates 5 major events that are ongoing. The semi-permanent MHW of the past 10 years in the Northeast Pacific has shifted west toward the Dateline and remains intense although no significant change during the past 30 days. This MHW will need to shift east toward the West Coast of North America for El Nino 2023 to become as intense as many dynamic models are indicating. A semi-permanent MHW either side of New Zealand persists and is slightly stronger during the past 30 days while a new MHW in the Southwest Indian Ocean is also strengthening. The MHW east of Argentina linked to semi-permanent high-pressure aloft extending into central South America and in-part the catalyst of drought the past 2 years has steady intensity. The newest MHW has emerged off the Northwest Coast of Africa to coastal Southwest Europe. The link of MHW’s to upper-level high-pressure ridging maintains a hot/dry summer concern for Europe if the MHW strengthens as observed in the Mediterranean Sea last year. The semi-permanent North Atlantic warm hole (NAWH) to the south of Greenland and Amundsen Sea cool pool well southwest of South America have weakened slightly during the past 30 days. All of these events have significant local and hemispheric impacts on our climate. Learn more from Climate Impact Company at GRAINCOM 2023 in Geneva, Switzerland May 15-17, 2023!