Taken from: https://forum.arctic-sea-ice.net/index.php/topic,3447.350.htmlA team led by physical oceanographers at Scripps Institution of Oceanography at the University of California San Diego, and including Bangor University scientist, shows in a new study how plumes of warm water are flowing into the Arctic Ocean from the Pacific Ocean and accelerating sea ice melt from below. . . .
The research primarily funded by the Office of Naval Research describes so-called underwater "heat bombs" as one of many mechanisms by which global warming-driven encroachment is changing the nature of the Arctic Ocean faster than nearly any other place on Earth. It adds to a growing body of evidence that suggests that Arctic sea ice, a source of global climate stability, could disappear for larger portions of the year. . . .
Because this water is saltier than the Arctic surface water, it is dense enough to "subduct," or dive beneath, the fresh Arctic surface layer. Its movement creates pockets of very warm water that lurk below surface waters. Scientists have been seeing these pockets of warm sub-surface water strengthen over the last decade.
These pockets known as "heat bombs'' are just stable enough to be able to last for months or years, swirling far north beneath the main ice pack near the north pole, and destabilizing that ice as the heat in them gradually but steadily diffuses upwards to melt the ice.
Original paper: https://phys.org/news/2021-04-arctic-sea-ice.html
We all know that lighter water (fluid) floats over denser water. Generally, warmer water is less dense than colder water (water expands as it gets warmer, the individual H2O molecules becoming more energetic, vibrating over a longer distance.) In the high latitude oceans salty water is heavier even than colder less salty (saline) water, water fed by freshwater runoff from land ice and melting older sea ice (as sea ice gets thicker and older it squeezes out the salt molecules.) The Pacific is a huge ocean especially around the tropics, unlike the Atlantic, so has plenty of warm water, some finding its way into the Arctic as we see above.
None of the previous discussion in the arctic sea ice forum has mentioned these underwater heat bombs. They will grow in number and intensity as AGW continues to heat the globe.