Antarctica’s sea ice hit another low this year – understanding how ocean warming is driving the loss is key
Retrieved on:
Tuesday, April 9, 2024
At the end of the southern summer, Antarctica’s sea ice hit its annual minimum.
Key Points:
- At the end of the southern summer, Antarctica’s sea ice hit its annual minimum.
- By at least one measure, which tracks the area of ocean that contains at least 15% of sea ice, it was a little above the record low of 2023.
- But something has changed in how the Southern Ocean works and the area covered by sea ice has decreased dramatically.
The southernmost shelf sea
- The annual freeze-thaw cycle of Antarctic sea ice is one of the defining properties of our planet.
- Time to take our medicine
The voyage was led by a team of scientists who coordinate Italy’s longstanding research in the Southern Ocean.
- Continental shelf seas around Antarctica are special because of the presence of sea ice – but this varies in space and time.
- It shows that by the end of summer, the Ross Sea region holds only a few patches of sea ice.
- The region is the southernmost open water on the planet and acts as a gateway to seawater flowing in and out under the largest (by area) ice shelf on the planet – the Ross Ice Shelf.
The state of sea ice
- This reinforced our understanding of the importance of the spatial variability of sea ice.
- At the late-summer sea-ice minimum, the Ross Sea is largely free of ice, while the Weddell Sea stays filled with ice.
- They took me beyond anything imagined from data and models.
- However, it is clear that Antarctic ocean data collection systems need to expand when and where they collect information.
The future is robotic
- We deployed 11 relatively simple Argo floats that will drift around the region for years, surfacing to send back data on temperature, salinity and in some cases oxygen.
- We also sent three robotic ocean gliders on their data-collecting missions independent of the ship.
- The data provide evidence of warmer water lying just beneath the edge of the continental shelf, highlighting the fragility of the system.
- There is a growing sense that the Ross Sea sector will become more important in the coming decade.
- Craig Stevens receives funding from the New Zealand Ministry for Business, Innovation and Employment (MBIE), Antarctica New Zealand Antarctic Science Platform (ASP-ANTA1801), MBIE Strategic Science Investment Fund and the New Zealand Royal Society Te Apārangi Marsden Fund.
- The observations and collaboration described here were made possible through long-term funding for the work from both the Italian PNRA (Programma Nazionale di Ricerche in Antartide) and the NZ Antarctic Science Platform.