Inside Climate News: Antarctic Sea Ice Decline Is Triggering Global Ocean Changes

The rapid decline of Antarctic sea ice since 2016 has triggered a dramatic shift in a crucial part of Earth’s climate system, scientists say. Researchers documented a sharp salinity increase in a vast layer of the Southern Ocean, extending from 2,300 to 4,000 feet deep and encircling Antarctica. The shift reverses decades of freshening and echoes ocean changes usually associated with major global climate shifts over millennia but is now happening in just a few years. The switch from a decades-long trend of freshening water to increasing salinity has implications that could extend beyond Antarctica. The layer, known as Antarctic Intermediate Water, spreads northward into the Indian, Pacific and Atlantic oceans, transporting heat, carbon, oxygen and nutrients toward the tropics, and even across the equator. A previous report in 2024 concluded that "The “speed and persistence” of the sea ice decline suggests the ocean around Antarctica may be moving into a new state that is likely to affect not only Antarctic ecosystems, but the entire global climate system. LINK.