You read that headline right, and no, I’m not a climate denialist. In a weird quirk, climate change has stopped the up-swelling of relatively warm ocean water in a specific area of Antarctic waters, resulting in it freezing over. A lid of fresh water, possibly from melting glaciers, has blocked that warmer salt water from reaching the surface.
“Deep ocean waters only mix directly to the surface in a few small regions of the global ocean, so this has effectively shut one of the main conduits for deep ocean heat to escape.”
If and when conditions change and the deep waters do surface “it will release decades-worth of heat and carbon from the deep ocean to the atmosphere in a pulse of warming.”