By George Moffatt • Education Chair, Jersey Shore Group
Choose a term, any term: marine heat waves, super marine heat waves, heat domes—each one a shorthand for the growing ways dangerous atmospheric warming is already overheating our oceans. A particularly intense example, known as The Blob, lingered off the west coast of North America from 2013 to 2016. It devastated marine populations and commercial fishing, drawing widespread attention to the mounting threat of prolonged ocean heat events.
New Jersey’s coastline has been experiencing “super marine heat waves” for the past three years, part of a worldwide explosion of unusually warm ocean waters.
We all know that atmospheric global warming is rapidly heating the world’s oceans to dangerous levels. But there’s a second, reinforcing phenomenon— marine heat waves—where unusually high temperatures develop on ocean surfaces, compounding the heat burden.
Oceans once had their own complex, natural regulators—seasonal cycles, ocean currents, salinity, depth—all of which shaped how heat was absorbed, stored, and moved around the globe. Now, the fate of marine life hinges on the size, surface temperature, area, and duration of these increasingly frequent marine heat waves.
Heat Wave Mechanics
These heat waves are essentially high-pressure atmospheric systems that trap and compress hot air into ocean surfaces already warmed by global heating. When that hotter surface water mixes downward into layers already warming from below, the result can devastate marine ecosystems—from benthic organisms such as plankton, sponges, and corals, to pelagic species such as fish, and the birds that prey on them. Commercial fishing takes a hit, too.
Historically, from 1901 through 2023, global ocean surface temperatures rose at an average rate of 0.14°F per decade, according to the US Environmental Protection Agency (EPA). A small bump? Not when you consider that oceans cover about three-quarters of the Earth’s surface and absorb over 90% of the excess heat—the additional thermal energy trapped by greenhouse gases that accumulates in Earth’s climate system —all while generating dangerous heat events of their own.
Interactive Map
In New Jersey, encounters with marine heat waves have been sporadic, although the North Atlantic is now plagued with them. A dramatic series of global heat maps from the New York Times (see here) shows this clearly.
In January 2024—the warmest January on record—nearly 40% of the ocean’s surface saw significantly higher-than-normal temperatures. By midyear, 2024 was already on track to become the warmest year ever recorded.
And just when we begin to recognize the solutions, we find—once again— that politics keeps them out of reach.
It seems our oceans may just have to keep taking it.
Resource
Interactive Ocean heat map: https://tinyurl.com/428p5njn