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Impact of Antarctic ice melting on Ocean currents

GS Paper 1/3

 Syllabus: Salient features of the World’s Physical Geography/ Conservation, Environmental Pollution and Degradation

  

Source: IE

 

Context: According to a new study, an alarming effect on the global temperature, the marine food chain and the stability of ice shelves is being caused by the Antarctic ice sheet’s rapid melting.

 

Background:

  • Ocean currents are the continuous, predictable, directional movement of seawater driven by gravity, wind (Coriolis Effect), and water density.
  • These overturning circulation/currents, driven by the movement of denser water towards the sea floor, helps deliver heat, carbon, oxygen and vital nutrients (rise up from the bottom) around the globe.
  • They have been relatively stable for thousands of years, but they are now being disrupted by the warming climate.

 

Findings of the study:

  • With temperatures rising → freshwater from Antarctica’s melting ice enters the ocean → reducing the salinity and density of the surface water → diminishing downward flow to the sea’s bottom.
  • Deepwater circulation in the Antarctic could weaken (by 40% by 2050) at twice the rate of decline in the North Atlantic.

 

The effect of meltwater on global ocean circulation:

  • Disrupts the base of the food chain: As the Southern Ocean supports about three-quarters of global phytoplankton production → impacts the marine ecosystem.
  • Leaving more CO2 in the atmosphere: The ocean would not be able to absorb as much CO2 as its upper layers become more stratified.

 

Insta Links:

 

Prelims Links: (UPSC 2021)

Consider the following statements:

  1. In the tropical zone, the western sections of the oceans are warmer than the eastern sections owing to the influence of trade winds.
  2. In the temperate Zone, westerlies make the eastern sections of oceans warmer than the western sections

Which of the statements given above is/are correct?

  1. 1 only
  2. 2 only
  3. Both 1 and 2
  4. Neither 1 and 2

 

Ans: 3