Context: New research published in the journal Nature, has found that 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.
What is overturning circulation?
- 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.
- Ocean overturning allows nutrients to rise up from the bottom.
What the study found
- 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.
- According to a study, deep ocean water flows from the Antarctic could decline by 40% by 2050.
- Disrupting the base of the food chain: The slow flow of water near Antarctica will slow down the whole circulation and will reduce the number of nutrients that get returned from the deep ocean back up to the surface.
- Leaving more CO2 in the atmosphere: 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.
- The study showed that warm water intrusions in the western Antarctican ice shelf would increase.
Definition of Antarctica: All the Land and ice shelves to the south of 60-degree latitude.
- It was signed in Washington on 1 December 1959 by the twelve countries whose scientists had been active in and around Antarctica during the International Geophysical Year (IGY) of 1957-58.
- It entered into force in 1961 and has since been acceded to by many other nations.
- The total number of Parties to the Treaty is now 56 (Including India).
- Antarctica should be used only for peaceful purposes. No country should build military bases.
- Freedom of scientific investigation in Antarctica.
- No country should claim sovereignty over Antarctica based on setting up of Research stations.
- No Nuclear explosions or disposal of radioactive wastes
- Countries to take appropriate efforts to abide by the provisions of the treaty.
India and Antarctica:
- India signed the Antarctic Treaty in 1983.
- India ratified the Convention on the Conservation of Antarctic Marine Living Resources in 1985.
- India signed Protocol on Environmental Protection to the Antarctic Treaty in 1998. (Madrid Protocol)
- India’s research stations in Antarctica: Dakshin Gangotri (De-commissioned now); Maitri and Bharati. Managed by National Centre for Polar and Ocean
- Research (NCPOR), Goa under the Ministry of Earth Sciences.
- Nov 2021: India launched its 41st Scientific Expedition to Antarctica.