In the context of which of the following do some scientists suggest the use of cirrus cloud thinning technique and the injection of sulphate aerosol into stratosphere?
- (a) Creating the artificial rains in some regions
- (b) Reducing the frequency and intensity of tropical cyclones
- (c) Reducing the adverse effects of solar wind on the Earth
- (d) Reducing the global warming ✓ UPSC's answer
Why the answer is (d)
• Both are proposed geoengineering techniques to counter global warming — option (d).
• Stratospheric aerosol injection would spray sulphate particles to reflect sunlight, mimicking the cooling after the 1991 Pinatubo eruption.
• Cirrus cloud thinning would seed high, thin cirrus clouds so they dissipate faster, letting more of Earth's heat escape to space.
• Neither is meant for artificial rain (a), cyclone control (b) or solar wind (c), and both carry risks such as altered monsoons.
• Hence option (d).
Why the other options are wrong
- (a) Creating the artificial rains in some regions
- These are not rain-making techniques.
- (b) Reducing the frequency and intensity of tropical cyclones
- They do not target cyclones.
- (c) Reducing the adverse effects of solar wind on the Earth
- Solar wind is a magnetospheric matter, unrelated.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2019, held on 2 June 2019. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.