A team of international scientists has detected an unprecedented phenomenon in the Southern Hemisphere: a reversal in the ocean circulation of the Southern Ocean. The study, published in PNAS, found that surface salinity has increased by 10% since 2016, suggesting that deep ocean circulation is being altered and has reversed.
Researchers from ICM-CSIC developed pioneering satellite observations to detect this change, which could accelerate climate change. According to Antonio Turiel, a researcher at ICM-CSIC, “We are witnessing a true reversal of ocean circulation in the Southern Hemisphere—something we’ve never seen before.” This reversal is believed to be driving accelerated melting of sea ice in the Southern Ocean.
The study’s findings have significant implications for global climate change. The upwelling of deep, warm waters could double current atmospheric CO₂ concentrations by releasing stored carbon, potentially leading to catastrophic consequences. The discovery highlights the urgent need to better understand ocean circulation and its role in regulating heat and carbon.
To improve monitoring and understanding of these processes, a new ESA-funded project has been launched: CCI OSHF (Ocean Surface Heat Flux). This project aims to develop new satellite methodologies that will help anticipate the effects of accelerated climate change. The findings emphasize the importance of satellite observation tools in monitoring remote regions like the Southern Ocean, which is sending clear signals about crossing critical climate thresholds.
The study’s lead author notes that “the planet is sending us increasingly clear signals that we are crossing critical thresholds.” As scientists continue to investigate and monitor ocean circulation changes, they must work together to understand and mitigate the effects of accelerated climate change.
Source: https://www.icm.csic.es/en/news/major-reversal-ocean-circulation-detected-southern-ocean-key-climate-implications