Rapidly melting Antarctic ice is dramatically slowing down the flow of water through the world’s oceans, and could have a disastrous impact on global climate, the marine food chain and even the stability of ice shelves, new research has found.
Key findings of the study:
- The “overturning circulation” of the oceans, driven by the movement of denser water towards the sea floor, helps deliver heat, carbon, oxygen and vital nutrients around the globe.
- These deep ocean water flows from the Antarctic could decline by 40% by 2050.
- Deepwater circulation in the Antarctic could weaken at twice the rate of decline in the North Atlantic.
- As temperatures rise, freshwater from Antarctica’s melting ice enters the ocean, reducing the salinity and density of the surface water and diminishing that downward flow to the sea’s bottom.
- Ocean overturning allows nutrients to rise up from the bottom.
- The Southern Ocean supports about three-quarters of global phytoplankton production, the base of the food chain.
- If there is slow sinking near Antarctica, it will slow down the whole circulation and so it will also reduce the amount of nutrients that get returned from the deep ocean back up to the surface.
- The ocean would not be able to absorb as much carbon dioxide as its upper layers become more stratified, leaving more CO2 in the atmosphere.
- Warm water intrusions in the western Antarctican ice shelf would increase.
|SOURCE: THE HINDU, THE ECONOMIC TIMES, PIB