A groundbreaking study by the National Oceanographic Centre in the UK reveals a drastic reversal in ocean circulation within the Southern Ocean. Since 2016, surface salinity has increased significantly, signaling a profound transformation in global climate patterns.
Traditionally, warm surface waters sink into the deeper ocean, but this process appears to be reversing. Instead, deep-water masses are surfacing, bringing with them heat and carbon dioxide that have been trapped for centuries. This flux is concerning, as it challenges long-standing assumptions about ice melt processes.
The increase in salinity occurs despite melting ice contributing to dilution of surface waters, which should promote conditions conducive to ice regeneration. The rise in surface salinity south of 50° S latitude undermines the mechanism that usually fosters sea ice formation.
If this trend continues, it could set off a long-term shift in the Southern Ocean with far-reaching consequences for global climate patterns, ocean currents, weather, and ecosystems beyond Antarctica. Current indicators suggest we are approaching a critical tipping point, entering a new phase of enduring sea ice decline perpetuated by a newly discovered feedback loop.
The potential global implications are staggering. Rising temperatures will intensify storms, accelerate climate change, and exacerbate the Antarctic ice sheet’s melting, leading to rising sea levels globally. The Southern Ocean’s meridional overturning circulation (SMOC) is weakening and reversing, with transparent implications for global climate dynamics.
The study’s findings invalidate previous assumptions that climate warming would lead to increased precipitation, contributing to freshening surface waters and maintaining relatively stable ice levels. Instead, the Southern Ocean’s reversal suggests a potential threat to global climates as significant as the anticipated collapse of the Atlantic Meridional Overturning Circulation (AMOC) in the North Atlantic.
The long-term effects of this reversal could double atmospheric CO₂ concentrations, releasing carbon that has lain dormant for centuries and posing catastrophic risks to the global climate system.
Source: https://www.capetownetc.com/world/groundbreaking-discovery-reveals-southern-oceans-circulation-has-reversed