Scientists have observed for the first time that heat from the ocean depths is moving towards Antarctica
A new study, based on oceanographic data collected by ships and robotic floating buoys over several decades, provides the first evidence that a warm mass of deep circumpolar water is approaching Antarctica, threatening the fragile ice shelves that border it from below. This warming in the Southern Ocean has implications not only for Antarctic ice melt and sea-level rise, but also for global heat regulation, carbon storage and the global climate system. The study is published in Communications Earth & Environment.
Javier Lillo - calor Antárida EN
Javier Lillo Ramos
Honorary collaborator of the consolidated research group on Terrestrial Global Change and Environmental Geology at Rey Juan Carlos University.
This research, carried out by the University of Cambridge in collaboration with the University of California and the Scripps Institution of Oceanography, provides direct evidence (based on an extensive, continuous collection of oceanographic data over recent decades combined with machine learning techniques) that the mass of warm ocean water known as Circumpolar Deep Water (Circumpolar Deep Water, CDW) has expanded and progressively moved closer to Antarctica over the last 20 years, affecting the stability of the ice shelves surrounding the continent, and thereby also the stability of the ice sheet and continental ice with which they are in equilibrium.
For the first time, there is direct evidence of this movement of deep ocean heat via the CDW in the Southern Ocean towards the Antarctic continent, an impact of global warming (already accounted for in climate models) linked to changes in both the position and intensity of the Antarctic Circumpolar Current (ACC) and the strengthening of westerly winds in the Southern Hemisphere.
The oceans are the largest reservoirs of the excess heat generated by global warming. As demonstrated in this study for the Southern Ocean, this causes serious alterations in the circulation of currents and the movement of oceanic masses, which in turn has significant impacts on the climate on a global scale.
In the case of Antarctica, there may be a feedback mechanism between the inflow of freshwater from glacial melt (which is less cold and dense) and the weakening of circulation due to the sinking of cold, dense water, which would facilitate the approach of the warm CDW mass to the continent. This, in turn, would lead to a weakening and retreat of the marginal ice shelves and increased melting of the continental ice sheets, resulting in a rise in sea level. This not only has implications for climate evolution, but these alterations in ocean circulation also have significant effects on nutrient transport and the global carbon cycle.
Joshua Lanham et al.
- Research article
- Peer reviewed
