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:
- In the tropical zone, the western sections of the oceans are warmer than the eastern sections owing to the influence of trade winds.
- 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 only
- 2 only
- Both 1 and 2
- Neither 1 and 2
Ans: 3
